Special Section : Plant Biotechnology

 

Total Phenolic Content Present in Tissue Cultures and Commercial Plantations of Cedrela odorata Linnaeus

Rebeca Lázaro-Felipe, Sugey Guillen-Vergara, Juan Manuel Zaldivar-Cruz, Elizabeta Hernández-Domínguez, Alejandro G. Nila-Méndez, Francisco J. Gabino-Roman

  • Abstract

    Plant- tissue in vitro culture is a method for massive propagation that can be used in forest species with high commercial values such as C. odorata L. The major problem during this process is the tissue phenolization known as browning. To overcome this, the relationship between explant age and total phenol content (TPC) of in vitro cultures (hypocotyls, cotyledons and callus masses), and commercial plantations (leaves and meristematic shoot tips) was evaluated. TPC was evaluated by the Folin-Ciocalteu method and results were expressed as μg of gallic acid equivalents (GAE)/g tissue. TPC values found in explants of commercial plantations were significantly higher than those found in in vitro culture. Leaves from 3-year-old trees showed the highest TPC values (455.87 ± 0.08 GAE/g tissue), while the highest values obtained from in vitro cotyledons were 36.18 ± 6.05 GAE/g tissue. TPC low values found in hypocotyls (22.4 ± 4 – 11.1±0.9 GAE/g tissue) did not affect the induction of organogenesis.

 

Somatic Embryogenesis and Genetic Transformation Protocols Effective on Neem Trees

Beatriz Zetina-Martínez, Sugey Guillen-Vergara, Alejandro G. Nila-Méndez,Francisco J. Gabino-Roman, Elizabeta Hernández-Domínguez.

  • Abstract

    To optimize an in vitro protocol for neem propagation via somatic embryogenesis, effects of various concentrations of dicamba, kinetin, TDZ and 2, 4-D (0, 0.5, 1.0 and 3.0mg/L) in combination with IAA or BA (0, 0.5, 1.0 and 3.0 mg/L) were studied. In fact, almost all the treatments showed the development callus masses with no evidence of proembriogenic masses. When hypocotyls and cotyledons were cultivated on MSB5 semisolid medium supplemented with 0.5 mg/L 2,4-D, 39% of the cultures displayed somatic embryogenesis. On the other hand, a genetic transformation protocol was developed to transform Azadirachta indica A. Juss via Agrobacterium. Four-week-old hypocotyls and cotyledons were used as explants in this transformation protocol. More than 35% of cotyledon and 65% of hypocotyl explants produced shoots on MSB5 medium supplemented with 1.0 mg/L 6-benzylaminopurine (BA). These explants were co-cultured with Agrobacterium tumefaciens, strain C58C1, harbouring the pCAMBIA 1303 plasmid, carrying the hygromycin resistance gene (htp II) as a selectable marker and β-glucuronidase (GUS) as a reporter gene. Factors affecting the transformation efficiency were evaluated; such as age and type of explants, Agrobacterium concentration, infection and co-cultivation time period, the presence of growth regulators, and the effect of cefotaxime on regeneration medium. Our results showed a 21% transformation efficiency when a 10-minute cocultivation period was employed. Putative transformed explants were immediately transferred to a regeneration medium in order to generate shoots.

 

Vanilla planifolia Andrews Response against Elicitor Staphylococcus aureus and Others Bacterial Compounds

Leal-Robles Aida Isabel, Cancino-Díaz Mario Eugenio,Cancino-Díaz Juan Carlos, Rico-Rodríguez Lilia.

  • Abstract

    Studies done in vitro report that plants can trigger a series of responses aimed at limiting the entry of an invader when they are exposed to foreign molecules or microorganisms, for example by increasing the synthesis of nitric oxide. Work aimed at studying the reaction that this plant has to foreign agents is null. The reaction vanilla leaves had against infections with Staphylococcus aureus, and components of the bacteria’s cell wall was studied. Vanilla plants were grown in vitro. The leaves were infected with S. aureus and E. coli. Researchers searched for bacterial growth and adherence with electron microscopy and for the production of nitric oxide (NO) with fluorescence. NO was also quantified on vanilla leaves treated with bacterial cell components. We detected the expression of defense genes that are induced by NO, was analyzed by RT-PCR. The electronic microscopy showed that S. aureus can adhere to the leaves tissues by the formation of biofilm which favors its growth over the tissue. On these leaves it was observed that the NO production was higher when leaves wereinfected with S. aureus compared with those infected with E. coli. The NO levels also increased (time dependent) when leaves were only treated with the bacterial cell wall components such as PGN and LPS. S. aureus as well as the PNG of this bacteria induced the mRNA expression of the AOS in leaf, stem and root of vanilla. A Pr1 overexpression was observed when the leaves were treated with both bacteria and with PGN and LPS. S. aureus induced an Pr1 overexpression also vanilla's stem and root. These results indicate that Vanilla planifolia can be colonized by S. aureus, but the plant responded by expressing genes via production of NO that alert the plant to protect itself from possible bacterial internalization

 

Obtaining of Polar Organic Extracts of Agave angustifolia and its Evaluation Antibacterial and Molluscicide

Nicte Morales-Rabanales, Lino Zumaquero-Ríos, Raúl Rojas-García, Odilón Vázquez-Cuchillo, Jerson López-Pérez, Alejandra Tovar-Corona.

  • Abstract

    The Agave angustifolia is a plant native to Mexico, commonly used for the production of mezcal and as an ornamental. It is well known that agaves, have active substances, a product of secondary metabolism like a steroidal saponins, which can be toxic to some types of pathogenic microorganisms. The present work describes the selective extraction of alcoholic phase fiber Agave angustifolia, their biological evaluation against bacterial strains in order to determine the effectiveness as inhibitors of bacterial growth and further it is isolated phytocompounds molluscicide evaluation as determining the LD50 and LD90 by an empirical Probit regression analysis.

    In the molluscicide evaluation the LD50 is 0.015g/20ml±0.003 and LD90 corresponds to 0.214g/20mL±0.056. Regarding its antimicrobial activity has the following zones of inhibition (mm) and inhibition percentage (%IR) based on the strain tested: S. epidermidis 15mm/20%, S. saprophyticus 15mm/23.5%, S. aureus 28mm/17% and Pseudomona aeruginosa 10mm/20.9%. This Polar extracts showed molluscicidal effects on a populations of Fossaria obrussa. Furthermore quantitatively established high antimicrobial activity against strains of environmental origin.

 

Genotypes of Sorghum Evaluated Under Two Moisture Conditions

Ana Belén Hernández-Hernández, Arturo Díaz-Franco, Noé Montes-García,Mario Efrén Nieto, Didiana Gálvez-López

  • Abstract

    Drought is an adverse factor affecting the sorghum crop production in Mexico.In order to find drought contrasting genotypes tolerant and susceptible for future molecular studies, an experiment was carried out under greenhouse conditions. A complete randomized design was used in a factorial arrangement, to test humidity (A): two moisture levels, irrigated and drought; and genotype (B): 20 genotypes. Results showed significant differences (P<0.05) between irrigation and drought conditions (factor A) in fresh stem biomass variable (298 vs 95 g), dry stem weight (111 vs 37 g), fresh root (84 vs 21 g), dry root (57 vs 9 g), and stomatal turgor index (819 vs 630). Among genotypes (factor B), there were significant differences only for stomatal turgor index, where RB-3030 genotype showed the highest values, followed by SBR-31 and Costeño; opposite, genotypes that expressed the lowest values were G-Star 7609 and Nus 421. With the above results, sorghum genotypes with higher values of stomatal turgor index can be useful to differentiate among genotypes and could be employed for differential genetic tags development on future molecular analysis. 

 

Podophyllotoxin-Like Lignans Production through Hairy Roots of Hyptis suaveolens

Crescencio Bazaldúa, Alexandre Cardoso-Taketa, Jesús Arellano, Brenda Camacho-Díaz, Elsa Ventura-Zapata, María Luisa Villarreal

  • Abstract

    The wild shurb Hyptis suaveolens also known as “chia” was used as food andmedicine since prehispanic times in Mexico, and nowadays is employed to treat several ailments. The anticancer lignan podophyllotoxin (PTOX) was recently reported in this plant,and its highest accumulation occurs in roots. This work reports the establishment of several lines of hairy root cultures of H. suaveolens producing PTOX. Three Agrobacterium rhizogenes strains (ATCC 15834, K599 + pGus-GFP+, and ATCC 15834 pTDT) were used to induce hairy roots. The strain 15834 of Agrobacterium rhizogenes carrying its wild type Riplasmid was transformed by introducing the TDT binary vector which contains the Tomato Threonin Deaminase gene. Hairy roots induced by infection with this new strain, showed red fluorescence; while those roots induced by infecting with K599+pGus-GFP+ showed green fluorescence as well as the expression of GUS gene. The transformed roots derived from explants infected with A. rhizogenes ATCC 15834 wild type exhibited the characteristic morphology of hairy roots. Fourteen root lines out of more than 100 lines obtained were selected. Cytotoxicity, fluorescence, GUS gene expression, growth rate and morphology, were used as selection criteria. Cytotoxic activity of different extracts obtained from these hairy roots against four cell lines of human carcinomas (KB, HF6, MC7 and PC3) was determined by the sulfurodamine B method. The cytotoxic values (IC50) of some root extracts were lower than 20 μg/mL, and some others even lower than 4 μg/mL. PTOX-like lignans, as β-peltatin and 6-methoxy podophyllotoxin (6-MPTOX), were identified by LC/MS.

 

Detection of Virus Damaging the Dry Bean Crop in Nayarit,Mexico

Elizabeth Chiquito-Almanza, Jorge A. Acosta-Gallegos, Nadia C. García-Álvarez,Wilmer Cuellar, Talina O. Martínez-Martínez, José Luis Anaya-López,

  • Abstract

    In the state of Nayarit, Mexico, the common bean crop is severely damaged by viral diseases. The aim was to identify the viral species that damage the bean crop in Nayarit, a knowledge needed to generate resistant cultivars for this state. During the fallwinter cycle 2013/14, forty-two samples of foliar tissue from plants displaying symptoms were gathered from fifteen commercial rainfed bean fields in the main producing areas of Nayarit. Total DNA was extracted from each sample to detect by PCR, DNA viruses andtotal RNA to detect via RT-PCR, RNA viruses. We use the primers that identify the eight most prevalent viruses in Latin America. In 45 and 52 % of the samples we detected BCMV and BCMNV, respectively. The genus Begomovirus was detected in 46 % out of 35 samples. In regard to samples showing single infection, 45 % were either infected byBCMV, BCMNV or a Begomovirus; in 43 % mixed infections were  etected, 14 % of those were BCMV and BCMNV, 10 % BCMV plus a Begomovirus, 14 % BCMNV plus a Begomovirus, and 5 % were a mixture of the three viruses. Undetected viruses were CMV, AMV, CPMMY, BYMV, PStV and PeMoV. Potyviruses BCMV and BCMNV were  the predominant viruses in the dry beans of Nayarit followed by the genus Begomovirus.Studies are being conducted to identify the Begomovirus species collected. 

 

Utilization of Seaweed Sargassum liebmannii Extract as a Stimulant of Germination of Pachyrhizus erosus

Nicolás-Álvarez Dulce Estefanía, Mateo-Cid Luz Elena, Mendoza-González A. Catalina,Gutiérrez-Ladrón de Guevara Miguel and Reyes-Chaparro Andrés.

  • Abstract

    Seaweeds are an integral part of the coastal ecosystem and they are known to aid and stimulate growth of vegetables, fruits and other crops. They contain all major and minor plant nutrients including bio-control properties; they also contain organic compounds such as auxins, gibberellins and precursors of ethylene and betaine that impact plant growth. A crude extract was prepared with 30 g dry weight of S. liebmannii. The solution was considered as 100% concentration and three different concentrations (2%, 5% and 10%) were prepared by dilution with distilled water. Four treatments were used (0%, 2%, 5% and 10%), with three replicates for treatment, and one hundred seeds for each replicate. Prior to germination, seeds were soaked in seaweed extract at treatment concentration for 24 h at room temperature (24 2 °C), and then placed on Petri dishes with filter paper. Seaweed extract had a significant effect on germination of Pachyrhizus erosus seeds (p<0.05). All concentrations promoted a higher germination percentage when compared to control treatment. Seeds exposed to the 2%concentration exhibited a 25% increase in seed germination in comparison with control treatment. There was a significant effect of S. liebmannii extract on germination time (p=0.0013). The results presented in this study clearly show the efficacy of Sargassum liebmannii extract promoting jicama seed germination percentage. 

 

Stevioside And Rebaudioside Extraction By Non-Conventional Techniques

Victor G. Canuas-Landero, Lluvia Rodriguez, Saúl Ramírez, Sandra L. Cabrera-Hilerio, Gabriel Ríos-Cortés, Alma L. Martínez, Joel Reyes, Minerva Rosas-Morales, Ada Ma. Ríos-Cortés.

  • Abstract

    Stevioside and rebaudioside A, diterpene glycosides, are gaining an increasing interest because of their sweetness taste, non-caloric characteristic, and medical properties. New non-conventional extractions techniques have been used instead of classical extractions with chemical methods due to high yields, rate extraction, and high efficiency on the use of solvents. Enzymatic assisted extraction, ultrasound-assisted extraction, and ultrasound-assisted enzymatic extraction were evaluated as non-conventional extraction methods under similar condition and same enzymes as well. All the extractions showed a similar behaviour with the yields of stevioside and rebaudioside A. The concentration of rebaudioside A was found 75% upper than that of stevioside which is favourable because rebaudioside A has more commercial interest.

 

Quantification of Candidatus Liberibacter Asiaticus In Mexican Lime Branches And Improvement of Early Detection In Asymptomatic Trees

A.A. Arratia-Castro, M.E. Santos-Cervantes, J.A. Chávez-Medina, J. Méndez-Lozano and N.E. Leyva-López

  • Abstract

    in infected branches and to improve the early detection of the pathogen in asymptomatic ML trees. Huanglongbing (HLB), the most destructive citrus pathosystem worldwide, is associated to Candidatus Liberibacter spp. and Candidatus phytoplasma spp. Early detection of HLB has been limited due to low titer and uneven distribution of the pathogen. In this study, a combination of an efficient DNA extraction method and nested TaqMan® PCR were used to examine the distribution of Candidatus Liberibacter asiaticus (CLas) in Mexican lime (ML) trees and to improve the early detection of the pathogen in asymptomatic trees. 8 symptomatic and 31 asymptomatic ML branches were collected in Colima in 2012. A modified CTAB method and DNeasy Plant Mini Kit were compared to identify the most suitable DNA extraction method for CLas diagnosis. Basal, middle and apical area of symptomatic branches were analyzed to determine CLas distribution. Samples were analyzed by TaqMan® PCR and nested TaqMan® PCR. The real-time PCR analysis showed that CLas was in all branches levels, but the highest concentration was found in the basal area of branches. The combination of CTAB DNA extraction method and nested TaqMan® PCR was the most effective method to determine the distribution of CLas

 

Isolation of Bacteria Associated With the Rhizosphere of Maize Forest Region of Chiapas, Mexico.

Arnoldo Wong-Villarreal  and Gustavo Yañez Ocampo

  • Abstract

    Plants were collected from two different maize varieties maize forest region of Chiapas, were isolated rhizosphere bacteria. Samples of the rhizosphere of maize were obtained 21 strains that grew in Rojo congo agar plates, IAA biosynthesis with L-tryptophan as precursor occurred in 4 bacterial strains, with IAA production ranging from 33 to 65 μg.ml-1. A total of four ARDRA profiles, clearly different were identified from isolates recovered from the and 2.2M2, had a differential effect on the variables Root weight fresh and dry weight and shoot weight fresh and dry compared to the control and the other strains tested. 21 strains were obtained from the rhizosphere of maize which four produce indoles, based on ARDRA profiles were observed that four profiles, which indicates that in the rhizosphere of plants native maize is low diversity of microorganisms, this may be because farmers use, lots of fertilizers and pesticide which affect the microbiota, as well as the characteristics of soil where the root system of plants is small because the soil is depth and many rocks, however in inoculation assays strains of maize plants had an effect on growth, which suggests that these bacteria is adapted to these conditions

 

Isolation and Identification of a Streptomyces Isolate that shows Antagonism against Sclerotinia sclerotiorum and Macrophomina phaseolina

Claudia M. Ramírez-Douriet and Melina López-Meyer

  • Abstract

    Streptomyces is the most abundant and diverse genus of actinomycetes. They are spore-producing bacteria that inhabit many different environments and are able to produce a great variety of secondary metabolites. In this work we explored their potential use for the control of plant pathogens, such as M. phaseolina y S. sclerotiorum in vitro and in plant. A collection of 127 Stretomyces-like microorganisms were screened for pathogen antagonism. Isolate “q” showed antagonism against S. sclerotiorum y M. phaseolina in vitro, and was identified as a species related to Streptomyces flavogriseus by DNA sequencing. However, this strain was only effective against S. sclerotiorum, but not M. phaseolina, when challenged on common bean leaves, which indicates that the plant host plays a role in the plant-microorganisms interaction. Antagonism against S. sclerotiorum was also demonstrated in common bean under field conditions. The results of the antagonism assays with extracts of the bacteria culture media obtained with different solvent systems suggest that the active compound (s) produced by isolate “q” is an apolar molecule since only the ethyl acetate extract showed antagonism against S. sclerotiorum. These results suggest that species of Streptomyces can be used as biological control agents against phytopathogens.

 

Evaluation Of Bacillus cereus Chitinases To Control Fusarium verticillioides in Maize

A.M. Figueroa-López, F.R. Quiroz-Figueroa, L.E. González de Bashan, I.E. Maldonado-Mendoza

  • Abstract

    Maize is the most important crop in Sinaloa, Mexico and it is attacked by diverse pathogens including Fusarium verticillioides. This fungal pathogen is responsible for causing root and stalk rot of maize and causes severe economic losses. Bacteria produce different compounds to inhibit the fungal pathogens, including the enzyme chitinase. The main goal of this work is to prove that in the endophytic Bacillus cereus strain (Bc25) the chitinases are involved in the antagonistic mechanism controlling Fv development in a maize plant. Bacillus cereus produces two chitinases (A and B). We have evaluated two inducers of chitinase activity (colloidal chitin and fungal lysate) and the gene expression level of Chitinases A and B were evaluated. Both chitinases are induced, however, chitinase B showed a higher induction than chitinase A in presence of both inducers. The Fv growth inhibition effect observed is possibly attributed to the chitinase production. We also have studied the localization of the bacteria in the root system concluding that it associates endophytically to maize by colonizing the apical zone and vascular vessels of the roots.

 

Studies On The Perezona Production In Different Culture Systems Of Acourtia Cordata (Cesr.) Turner (Compositae).

Geronimo Peña, Gabriela Gómez, Juan Nava and Thelma Lilia Villegas

  • Abstract

    Perezona is a sesquiterpenic benzoquinone, which accumulates in the roots of several Acourtia species. This compound has proved to be of great value. The aim of this work was to study the effect of conditions in vitro and ex vitro culture perezona production over time, further develop and validate a method that allows for the selective quantification of perezona. Perezona crystals were obtained from hexane extraction. Perezone was characterized by several analytical methods, using the crystallized compound isolated from roots of wild plants as standard. The roots of plants ex vitro increased perezona production from 2.4 mg /g dry weight at 12 weeks to 43.6 mg /g dry weight at 31 weeks. A procedure was developed for perezone selective quantification in its non-ionic and ionic forms. The present study shows the feasibility of using in vitro culture systems to propagate and conserve the Acourtia germplasm for a large number of ex vitro plants and extract perezona comparable to the levels obtained in wild plants.

 

Micropropagation Of Acourtia cordata (Cerv.) Turner (Compositae), Native Species Of The Natural Protected Area “Sierra De Guadalupe”

Gabriela Gómez and Thelma Lilia Villegas

  • Abstract

    Plants of the genus Acourtia are known and used in Mexico since pre-Columbian times by the properties of the dye that accumulates in roots; nevertheless, at the moment the natural populations of these plants tend to be small and the areas in which they grow present a considerable deterioration, such is the case of the protected natural area "Sierra de Guadalupe". The aim of this work was to establish protocols for micropropagation of A. cordata plants through culture of axillary buds, apical and shoot induction by indirect organogenesis in medium of Murashige and Skoog with 5 mg/L of IAA and 0.5 mg/L BAP, followed the rooting in presence of IBA. A propagation factor of 22 ± 2 plants per germinated seed was obtained in 6.5 months. The results of this work support the importance that the culture systems have in vitro like a biotechnological alternative to spread, restore and preserve the valuable germplasm of a region, as well as for the study of biosynthesis and production of metabolites plant with a high potential medical and industrial as it is the case of the perezona.

 

Epitope Prediction by Protein B8Y674 Present in Candidatus Liberibacter asiaticus

Cynthia G. Rodríguez Q, Aldo Segura C, Isidro H. Almeyda L and Alberto Mendoza H.

  • Abstract

    Huanglongbing (HLB) is considered the most destructive disease of citrus world wide, caused by the bacterium Ca. Liberibacter spp, of which three species are known: americanus, africanus and asiaticus, the final is present in Mexico. This bacterium has not been cultured in the laboratory. It is confined to the phloem and transmitted by two insect vectors: Diaphorina citri and Trioza erytreae. Once the trees are infected there is no cure and died in a few years. Official methods of its detection are based on conventional PCR and molecular qPCR methods. However, these methods are confirmatory and are not available to everyone. Thus our objective was to lay the foundations for develop an immunological screening method by predicting present epitopes in outer membrane protein B8Y674 of Ca. Liberibacter asiaticus. The prediction of antigenic determinants was using the Linear Epitope Prediction method BepiPred (IEDB Analysis Resource), presented at 75% specificity, obtaining 16 epitopes, which epitopes resolved by Immune Epitope Database and Analysis Resource (http: //www.iedb. org /), obtaining three epitopes that have been tested experimentally validated with 70% identity. Which could be three potential third party candidates for the development of the immune method?

 

Spatial Distribution of A. brasilense CBG-497 in Roots of Conventional and Genetically Modified Maize

Lourdes Vital L., Ma. Antonia Cruz H., Susana Fernández D., Luz E. de Bashan and Alberto Mendoza H. 

  • Abstract

    Despite the on-going public debate on transgenic crops, the adoption rate for use and commercialization of genetically modified is growing continuously yearly since these crops were first adopted (1996). The transgenic plants into agricultural ecosystems have scientifically interesting questions of the potential ecological effects of these crops on rhizosphere microbial communities, because of their intimate proximity. In this study, we evaluated if the transgenic maize (resistance herbicide) induce an effect on Azospirillum brasilense CBG-497 strain inoculated in their roots in comparison with conventional maize. The spatial distribution of A. brasilense CBG-497 in both type of maize was analyzed by Fluorescence in situ hybridization (FISH) technique. Our results demonstrated that the transgenic maize had no effect on the spatial distribution, because they were found in same zones of roots in transgenic and conventional maize. Furthermore, the bacterial densities were calculated and the statistical analysis showed that no significant differences were found between both types of maize.

 

Characterization Of Sphingobium Sp. Isolated From The Rhizosphere Of Sorghum And Its Possible Role In Biodegradation

Claudia Paola Mendoza Charles, Antonia Cruz Hernández, Icoquih Zapata Peñasco Alberto Mendoza Herrera.

  • Abstract

    The growing population, industrialization and increased petroleum activity has resulted in the contamination of various natural systems by petroleum and other petroleum products that are often persistent and difficult to remove pollutants from the environment: Thus the use of bacteria capable of degrading these compounds has proven to be an effective alternative for the recovery of contaminated environments. Among these microorganisms must be remark bacteria of the genus Sphingobiumas its main feature is the degradation of hydrocarbons. Therefore, the objective of this study work was the identification of the involved genes in biodegradation of a strain of Sphingobium sp., Isolated from the rhizosphere of sorghum in northern Tamaulipas. The bacteria studied were identified to species level by phylogenetic, biochemical and morphological analysis by SEM and TEM as Sphingobium yanoikuyae strain S72. Also we amplify and perform sequence analysis of two key genes in the process of biodegradation of biphenyl, naphthalene, phenanthrene and toluene. Moreover, positive results obtained in the in vitro evaluation of the degradation of crude oil.

 

Obtaining Hairy Roots of Acourtia hebeclada DC for Production of Perezone

Ma. Ileana Muñoz-Sandoval, Patricia Castillo-España, Irene Perea-Arango, Alfonso Leija-Salas, Alexandre Cardoso-Taketa, J. Jesús Arellano-García

  • Abstract

    Genus Acourtia contain more than 110 species that produce and accumulate in their roots a wide variety of sesquiterpene quinones and related compounds. Between such plant species Acourtia hebeclada DC, known as pipitzáhuac, produces the sesquiterpene quinone perezone. Perezone forms deep orange color crystals which reduces readily and reoxidizes spontaneously. This substance can be used as pigment, as antimicrobial agent and possesses several pharmacological activities. We established a protocol for obtaining hairy roots from A. hebeclada by infecting leaf explants from in vitro cultured seedlings with the A. rhizogenes strain ATTC 15834/pTDT-RNAi. Then infected and control explants (not infected) were placed in Murashige and Skoog co-culture medium amended with sucrose, α-naphthaleneacetic acid, 6-benzylaminopurine and acetosyringone. After cocultive explants were subcultured on half strength MS medium containing ceftriaxone and cefotaxime to eliminate Agrobacterium. Transformed hairy roots were observed 21 to 28 days after infection under epifluorescence microscope and fluorescent roots were selected. During the selection process we found red fluorescent hairy roots but others that were non fluorescent as well. Selected hairy roots were grown to produce enough biomass to make hexane extracts and HPLC analysis. The chromatograms obtained revealed presence of sesquiterpene related compounds.

 

Azospirillum Brasilense Altering Root Architecture of Arabidopsis thaliana Through TOR Kinase

E. Carrillo-Flores, Manuel Méndez-Gómez, María Elena Mellado-Rojas, Homero Reyes de la Cruz, Ernesto García-Pineda and Elda Beltrán-Peña

  • Abstract

    Plant root development is highly responsive both to changes in nutrient availability and beneficial microorganisms in the rhizosphere. Plant development involves the integration of environmental and endogenous signals, which together with genetic program it determines plants form. The auxins modulate every aspect of plant growth development and, it has been proposed that Azospirillum produces auxins between other phytoregulators. In metazoans insulin and IGFs can activate the PI3K/TOR /S6K cascade that play a central role in cell growth regulation. Many reports have described in plants the presence of various components of such cascade. Our results showed that A.brasilense alters the Arabidopsis root architecture: reducing (70%) PR length and increasing (150%) the number of LRs and root hairs, suggesting TOR involvement, since in its absence (tor-es1 mutants) the PR length is 32% shortened only and although the increase on the number of LRs was (360%) very dramatic, these roots were very small and root hairs development is severely affected.

 

Salicilic Acid Effect on Carotenoid Production and Carotenogenic Gene Expression of in vitro Culture of Marigold

Israel Benítez García Pablo Emilio Vanegas Espinoza, Octavio Paredes López y Alma Angélica Del Villar Martínez

  • Abstract

    Carotenoids are of interest for natural food colorants uses and have been relevant against protection from a range of diseases. In vitro culture of Marigold (Tagetes erecta) shows potential for commercial production of carotenoid pigments this has led to the application of elicitation of vegetal culture for improved production of pigments. In these context, elicitation with salicylic acid (AS) have also been shown to induce the carotenoid biosynthetic pathway, and can be applicate to the in vitro culture of T. erecta for improved production of carotenoid. In our study carotenoid pigment accumulation was significantly increased when elicited with SA in comparison to the control. Transmission electron microscopy showed cellular alterations in elicited cultures and highest electro density plastoglobules in comparison to the control. Transcriptional expression patterns of carotenoid genes indicated that elicitor change transcriptional expression of four carotenoid gene, these genes exhibited different expression profiles, carotenoids biosynthesis under SA was up-regulated mainly by psy, pds and lcyb and down-regulate by lcye at transcriptiona level. Summarily, these results suggest that SA constitute molecular signals in the network of carotenoids biosynthesis. Induction of total carotenoids accumulation by AS without any other stimuli presents an attractive application potential in suspension culture of T. erecta.

 

Polycistronic Expression Of Heterologous Proteins In Chlamydomonas reinhardtii

Karla Macedo-Osorio, Víctor Pérez- España, Noé Durán-Figueroa, Jesús Agustín Badillo-Corona

  • Abstract

    Chlamydomonas reinhardtii has emerged as a very attractive model organism for chloroplast genetic engineering. Engineering of complex metabolic pathways requires the expression of multiple genes. Ten percent of chloroplast genes of C. reinhardtii are conformed as polycistronic transcripst and then further processed into monocistronic mRNAs. Polycistronic genes are separated by intercistronic regions which contains translation regulatory elements that allow individual expression of polycistronic genes. We evaluated the effect of using intercistronic regions from C. reinhardtii chloroplastic genes in the bicistronic expression of two exogenous genes. The two genes were the kanamycin resistance gene (aphA6) and the green fluorescent protein (gfp). We detected gfp and aphA6 presence in transformed colonies by PCR. The gfp expression was detected by fluorescence. Two of the eight intercistronic regions found in the chloroplast genome of C. reinhardtii were shown to be functional for the expression of exogenous genes in the algal chloroplast.

 

Physicochemical Analysis of Protein Fractions of Mesquite (Prosopis spp) Seeds

Luis A. García-Beltrán, Yolanda L. López-Franco, Alma R. Toledo-Guillén, Karla G. Martínez-Robinson, Jaime Lizardi-Mendoza

  • Abstract

    Physicochemical analysis and amino acid composition of protein fractions from mesquite seeds native of Sonora State was investigated. Albumin, glutelin, globulin and prolamin of defatted mesquite seed meal were obtained according to the Osborne method. The protein content, molecular weight, chemical identity and amino acid compositionwere determined. Defatted mesquite seed protein fractions were 18.6% albumins, 61.9% globulins, 8.9% glutelins, and 10.5% prolamins. SDS-PAGE of the albumin fraction showed 6 major bands at 10, 20.5, 22, 28, 40 and 41 kDa, globulin showed 4 major bands around at 6.5, 18, 23.5 and 38 kDa, glutelin resolved into 5 bands at 6.5, 18, 23.5, 25 and 40 kDa, and prolamin fraction showed 5 major bands around at 6, 18, 23, and 40 kDa. Fractions FT-IR spectrum showed the amide A bands at 3320 cm-1, amide I at 1650 cm-1, amide II at 1540 cm-1 and amide III at 1240 cm-1. The levels of essential amino acid of globulin and glutelin fractions were similar and higher compared with albumin and prolamin fractions. This study showed that mesquite seed meal contained four protein fractions in varying proportions with different molecular weight and amino acid composition.

 

MiRNAs Involved In Prickly Pear Cactus Fruit Development

Flor de Fátima Rosas Cárdenas, Nayelli Marsch Martínez, Silvia Luna Suárez, Andrés Cruz Hernández, Stefan de Folter

  • Abstract

    MiRNAs are involved in many processes including the fruit development. The information available on miRNAs in plants species provides an opportunity to study the role of miRNAs in non-model species, such as Opuntia ficus indica. We analyzed dozens of miRNAs in prickly pear cactus and demonstrated that at least 32 miRNAs are expressed during prickly pear cactus development. These miRNAs revealed dynamic expression patterns through different stages of prickly pear cactus fruit development. A gradual increase in the expression of several miRNAs, including miR164, was observed during fruit development. Detailed spatial-temporal analysis of this miRNA during prickly pear cactus fruit development showed that miR164 is localized in meristematic tissues, boundaries and fusion zones before fertilization, and expressed homogeneously in all tissue after fertilization; suggesting that miR164 participates in different processes during prickly pear cactus fruit development. This is the first report of miRNA expression profiles during prickly pear cactus fruit development and provides the basis for future research on miRNAs in Opuntias.

 

Callus Production of Medicago sativa as a Natural Source of Nanoparticles

MA Dávila-Uribe1, JJ Torres-Ruíz, J Orozco-Villafuerte, F Cruz-Sosa, E Villagrán-Vargas, L Buendía-González

  • Abstract

    In recent years, remarkable progress has been made in developing nanotechnology. Metallic nanoparticles have a variety of applications due to their unique properties. Several biological systems are able to produce metallic nanoparticles at ambient temperature and pressure without requiring hazardous agents and generating poisonous by-products. The aim of this work was the callus production of Medicago sativa and biomass proliferation as a natural source of metallic nanoparticles production. Explants from seedlings germinated in aseptic conditions, were inoculated in test tubes containing Murashige and Skoog (MS) medium supplemented with different concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) with 6-benzyladenine (BA) or kinetin (KIN). The cotyledon and hypocotyl were the explant that showed the highest percentage of callus induction (100%) in MS medium containing 1.0 mg/L 2,4-D and 1.5 mg/L BA. Additionally, other cell line was proliferated, which showed the capability of synthesizing pigments. On the other hand, was initiated the establishment of cell suspension cultures, corroborating that the produced callus showed high friability in liquid medium. Medicago sativa has been employed in studies for nanoparticles production, but the characteristics biomass was associated to the quality of nanoparticles. So far, the biomass production through of plant cell tissue can be a natural source under conditions controlled

 

Isolation, Characterization and Determination of Cellulolytic Activity of F. oxysporum on Green Vanilla Beans

Lizbeth Rosas, Marco Marín, María Cassellis, Braulio Herrera, Juan Luna and María Luna

  • Abstract

    Vanilla bean (Vanilla planifolia) is a high value crop in Mexico, however a major obstacle for farmers are fungal diseases, especially that posed by Fusarium which causes vanilla wilt. For this reason, the aim of this study was to isolate, characterize and determine hydrolysis of cellulose (HC) of F. oxysporum on green vanilla beans. Vanilla beans with symptoms of basal rot were employing to isolation of F. oxysporum. Fungal cultures, rapidly growing colonies with white aerial mycelium initially and changes over time were presented to purple. Microscopically, had short, simple, with side and densely branched conidiophores monofiálides. Fusiform macroconidia of alantoespora type (23-54 and 3.0-4.5 μm), slightly curved, with three to five septa and pedicellate basal cells. HC were determined by plate assays and enzymatic-activity (EA) with 0.1, 0.5 and 1% (w/v) carboxymethylcellulose (CMC) at pH 5 and 7. The colonies and zone of clearance (diameter) were measured and analyzed with an experimental coefficient (DC values) and EA (IU) were determined by reducing sugars using dinitrosalicilic acid (DNS). F. oxysporum increased DC values with low concentrations of CMC in both pH, however the principal EA showed with pH 5 and 0.1% of CMC.

 

Pharmacological Evaluation of Three Commercial Echinacea Extracts

Rayn Clarenc Aarland, Laura Josefina Pérez Flores, Fernando Rivera-Cabrera, Fernando Díaz de León Sánchez, José Alberto Mendoza-Espinoza

  • Abstract

    Echinacea is one of the plants used to treat different illnesses since prehispanic times thanks to its pharmacological properties. Actually, Echinacea is sold in different forms, such as hydroalcoholic extracts and used for its antioxidant properties. These extracts are being prepared in standardized manufacturing conditions, guaranteeing the quality of the biological material but they lack any kind of chemical assessment that allows the standardization of the extract. This chemical assessment is based on the determination of the major chemical groups, obtaining fingerprints, quantification of some of the metabolites and pharmacological effect in animals. We used three commercial Echinacea extracts: Echinacea®, Super Echinacea® and Echinacea Supreme®. Test tube reactions were carried out to determine the presence of tannins, coumarins, saponins, anthraquinones and alcaloids, qualitatively. Antioxidant activity was determined using the DPPH and ABTS method. We found tannins and coumarins in Echinacea® and Super Echinacea®; anthraquinones in Super Echinacea® and Echinacea Supreme®; saponins in the three commercial extracts but no alkaloid presence. The chemical group differences may have an impact on the pharmacological effect. The pharmacological and chemical results showed significant differences, however in the clinical use, the manufacturers recommend using the same dose in the different extracts.

 

DNA Macroarray For Simultaneous Detection Of Pepper Wilt Pathogens

David B. García-Piza; Talina O. Martínez-Martínez, José L. Anaya-López, Luis A. Mariscal-Amaro

  • Abstract

    Pepper production is affected by wilt disease complex, Phytophthora capsici, Rhizoctonia solani and Fusarium spp are frequently involved. The first action to provide control measures is the identification of the causal agent; however the classical diagnostic is time-consuming, laborious, and require taxonomy knowledge. Therefore, previously this work were generated DNA macroarrays to identification of pathogens using ATTC strains and amplified ITS regions of fungal and oomycetes simultaneously, the PCR products were labeled with alkaline-labile. The generation of DNA macroarrays was realized in according to Lievens et al. (2003). This molecular method showed efficient and simultaneous detection. The objective of this research was validated the method using infected plant tissues. Total DNA of stem, root and a mix of both tissues was extracted using three commercial kits. The quality and yield of the DNA was highest when using UltraClean Plant DNA Isolation Kit. Only total DNA from stems permits the PCR amplification of ITS regions. The length of fungal and oomicetes ITS was 650 pb and 850 pb, respectively. Two fragments were amplified in the presence of both pathogens. The results suggest that the methodology is highly specific and can be employed in early detection of pepper wilt pathogens in seedlings

 

Obtaining of Polar Organic Extracts of Agave angustifolia and its Evaluation Antibacterial and Molluscicide

A. Tovar, O. Vázquez3, L. Zumaquero, R. Rojas, Q.N. Morales, J. López

  • Abstract

    The Agave angustifolia is a plant native to Mexico, commonly used for the production ofmezcal and as an ornamental. It is well known that agaves, have active substances, a product of secondary metabolism like a steroidal saponins, which can be toxic to some types of pathogenic microorganisms. The present work describes the selective extraction of alcoholic phase fiber Agave angustifolia, their biological evaluation against bacterial strains in order to determine the effectiveness as inhibitors of bacterial growth and further its isolated phytocompounds molluscicide evaluation as determining the LD50 and LD90 by an empirical Probit regression analysis. In the molluscicide evaluation the LD50 is 0.015g/20ml±0.003 and LD90 corresponds to 0.214g/20mL±0.056. Regarding its antimicrobial activity has the following zones of inhibition (mm) and inhibition percentage (%IR) based on the strain tested: S. epidermidis 15mm/20%, S. saprophyticus 15mm/23.5%, S. aureus 28mm/17% and Pseudomona aeruginosa 10mm/20.9%.This polar extracts showed molluscicidal effects on a populations of Fossaria obrussa. Furthermore quantitatively established high antimicrobial activity against strains of environmental origin.

 

Oil Spotting: The Main Problem to Solve in Persian Lime(Citrus latifolia Tanaka) Minimally Processed

Fernando Rivera-Cabrera; Denise Raddatz Mota, Iran Alia tejacal, Jose A. Mendoza Espinoza, Fernando Díaz de León Sánchez, Laura J. Pérez Flores.

  • Abstract

    Minimally processed produce is a very fast growing segment of the food industry. Wounding stress caused by processing operations such as peeling, cutting and grating induce metabolic activation, increasing enzyme activity, respiration rate and loss of firmness. In particular, in lime, the release of essential oils from the oil glands during processing causes oil spotting, the main limitation for fresh-cut limes. Even though, PPO enzyme activity has been detected in some citrus (orange and tangerine), there are no reports of PPO participation in flavedo browning during oil spotting in lime. The objective of the present study was to determine the PPO participation in the browning observed in fresh-cut Persian lime. Limes were cut in 8 wedges in a cold room at 10 °C. Different treatments were applied: a) cutting under water (CUW) at 4ºC and b) cutting under water at 4ºC with 4-hexilresorcinol and calcium lactate, individually or combined. Our results showed that the best treatment was cutting under water with calcium lactate, since it decreased oil spotting levels and damage in comparison to the other analyzed treatments. PPO enzyme activity was not detected in any of the applied treatments.

 

Rescue and Bromatological Evaluation of the “Tlalayote” Matelea sp. Endemic Plant

I. Y. Vázquez-Carmona, L. F. Cosio-Castillo, L. Saucedo-Berruecos, C. Sánchez, A. H. Hernández-Portillo, J. V. Cervantes-Mejía and M. Cuamatzi-Muñoz

  • Abstract

    Germoplasm six endemic plants that produce fruit, the western region of the state of Tlaxcala, Mexico, was collected. Seeds collected were: Phytolacca icosandra, Asclepias notha, Solanum sp, Jaltomata procumbens, Matelea sp., and the last one that still has not been identified. These species were planted in the experimental will only drive Matelea sp. germinated after 24 days. As the fruits of this plant are consumed regularly by people of the region, it was considered to make a bromatological analysis of them to assess their nutritional potential. The results showed that 100 g of the fruit contain: 82.37% moisture, 1.47% ashes, 7.00 % crude protein, 3.11% corresponds to ethereal extract and 82.56 % crude fiber. According to these results, the wild fruit "Tlalayote" can be considered as a beneficial food for human health; since it is rich in protein, water and crude fiber. Moreover, the adaptation of this species was achieved in the experimental unit. This can be of great impact on the people of the region as an alternative agricultural production.

 

Genotypes of Sorghum Evaluated Under Two Moisture Conditions

Didiana Gálvez-López, Ana Belén Hernández-Hernández, Arturo Díaz-Franco, Noé Montes-García

  • Abstract

    Drought is an adverse factor affecting the sorghum crop production in Mexico. In order to find contrasting genotypes tolerant and susceptible for future molecular studies, it was evaluated 20 genotypes under two moisture conditions, irrigation and drought on greenhouse. One completely randomized design was employed in a factorial arrangement A (humidity) x B (genotype). Results showed for irrigation and drought soil conditions (factor A) significant values of biomass (P<0.05) for stem fresh (298 vs 95 g), stem dried (111 vs 37), root fresh (84 vs 21 g), root dried (57 vs 9 g), and stomatal turgor index (906 vs 630) on sorghum genotypes. Among genotypes (factor B), it was only observed statistical significance for stomatal turgor index, where the RB-3030 was the genotype with highest values, followed by SBR-31 and Costeño; opposite, genotypes that expressed the lowest values were G-Star 7609 and Nus 421. In earlier studies the stomatal turgor index allowed to differentiate tomato genotypes under salt stress conditions. With the above it deduces that sorghum genotypes with higher values, could be predicted like possible tolerant to drought and employed for differential genetic tags development on future molecular analysis.

 

Effect Of Three Growth Regulators In Callus Induction, Shoots And Plants Of Jatropha curcas By In Vitro Culture

Denisse Téllez Mazzocco , Jorge Alberto Hernández Hernández  and Rubén Domingo Fernández.

  • Abstract

    The Jatropha curcas has great potential for industrial, medicinal and food. The conventional method of propagation by seed or cuttings produces plant with high genetic variability, which in the future will cause problems in agribusiness uses. The in vitro regeneration through tissue culture techniques is important for the productivity of this crop because obtaining genetically identical plants enabling the propagation of varieties elites massively. The objective of this work consisted in evaluating the effect of various concentrations of plant growth regulators (2-4-D, BAP and IBA) in the induction of callus, shoots and plants of Jatropha curcas. The response variables were assessed by analysis of variance. For the induction of callus were used segments of young leaves, presenting the treatment T2 (AIB 0.1 mg/l BAP 0.1 mg/l), T4 (AIB 0.5 mg/l BAP 0.25 mg/l) and the T5 (AIB 0.25 mg/l 2, 4-d 0.1 mg/l) a 20% induction being the best treatments. To obtain shoots were used stems being the T4 treatment the best with four outbreaks. To obtain plants were used embryos being the treatment T4 (AIB 0.25 mg/l BAP 0.5 mg/l) the best with a percentage of germination of 90%.

 

In vitro Propagation of Maguey Pulquero (Agave salmiana Otto ex Salm) Var.,| Púa larga

Areli Flores-Morales, Ángel Jiménez Rodríguez, Paulina Heredia Guzmán, Víctor Manuel Chávez Avila, Octavio González Caballero, Alfonso Sánchez Contreras.

  • Abstract

    Maguey pulquero (Agave salmiana Otto ex Salm) can be considered an endangered species. The present study was to establish aseptic cultures that they contribute to plant regeneration via indirect organogenesis. The culture was initiated from leaves and stems explants on modified Murashige and Skoog (MS) medium (50% conc. of mineral salts), supplemented with different concentrations of 6-benzyladenine (BA)/naphtaleneacetic acid(ANA) (Treatment A); naphtaleneacetic acid (ANA)/Kinetin (K) (Treatment B); in different concentrations (0/0, 1/1, 1/2, 2/1 mg/L). Callus formation and growth was stimulated under 1:1 and 1:2 mg/L of BAP/ANA. However, all explants showed oxidation (75%/90 days).The proportion of the contamination in explants was 37%. All cultures were subcultivated on MS medium (50%, mineral salts, 0.5 g/L activated charcoal) supplemented with BA/ANA (1:1 mg/L). The oxidation decreased and callus development. Treatment B (2:1 mg/L) promoted the best response on callus formation (80%) in 30 days. The cultures of stem sections were of slow growth on MS media supplemented with hormonal (treatment A and B) (30 day). The best effect on bud development was in the combination BA/ANA (1:1 mg / L) that stimulated axillary’s bud breaking and growth. The results of this study are important for the purpose of micropropagation of agaves.

 

Partial Characterization of a Cysteine Peptidase (TcCys) From Cacao Fruits (Theobroma Cacao) Variety Criollo-White Almond

M. Sanchez Mundo, R. García Barrientos, C. Bautista Muñoz and M. Jaramillo Flores

  • Abstract

    Enzymes, especially peptidase, have become an important and indispensable part of the processes used by the modern food and feed industry to produce a large and diversified range of products for human and animal consumption. A cystein peptidase, used extensively in the food industry, was partially characterized from germinated cacao seeds (Theobroma cacao L.) variety “criollo white-almond” through a simple reproducible method consisting of extraction, precipitation with 30% ammonium sulfate and two ion exchange chromatographic steps. The relative molecular weight of the enzyme was estimated to be 25 kDa by SDS-PAGE. The cystein peptidase had a pH optimum at 5.0. In addition, it had a temperature optimum of 50°C and based on a thermal stability study, its stable at 60°C after preincubation of the enzyme for 1 h prior to substrate addition. The proteolytic activity of the enzyme was inhibited by thiol-specific inhibitor, p-chloromercuribenzoate and recovered by reagents reductor such as glutation, βME and dithitreitol.

 

Epigenetic Analysis of The Pathogenicity of Macrophomina phaseolina (Tassi) Goid.

Nubia Andrea Villota-Salazar, Sanjuana Hernández-Delgado, Juan Manuel González-Prieto.

  • Abstract

    Epigenetic mechanisms like DNA methylation and histone modifications regulate gene expression and control the cell specialization. It is known that fungal pathogenesis involves cell differentiation. Macrophomina phaseolina (Tassi) Goid. is a cosmopolitan and aggressive plant pathogenic fungus with a broad host range (more than 500 species) including common bean (Phaseolus vulgaris L.). We analyzed the pathogenicity of Macrophomina phaseolina on P. vulgaris L. from an epigenetic perspective using the histone acetyltransferase inhibitors, garcinol and CPTH2. We identified the potential molecular targets of these inhibitors on M. phaseolina. Garcinol and CPTH2 affected significantly fungal growth rate, macroscopic morphology of colonies and microsclerotia diameter on solid minimum medium. In spite of this, we did not find evidence of changes in the ability of the fungus to produce disease in the plants of P. vulgaris under the inhibition conditions tested. Moreover, it was assessed the expression of some pathogenicity genes in plant-fungus interactions using RT-PCR assays. The increased expression level of PMK1 under the effect of garcinol with respect to the controls suggests that this inhibitor could deregulate the MAPK pathway, which has been related to fungal pathogenesis.

 

Cell Suspension Culture Of Bursera linanoe For Production of Linalool And Linalyl Acetate

Leticia Pavón-Reyes, Silvia Evangelista-Lozano, Gabriela Sepúlveda-Jiménez, Víctor Chávez Ávila and Mario Rodríguez-Monroy

  • Abstract

    For the production of monoterpenes linalool and linalyl acetate from Bursera linanoe suspension culture, callus was obtained with the combination of Naphthaleneacetic acid (3.0 mg/L-1) and 6-Benzylaminopurine (0.5 mg/L-1), using axillary buds as explants. The kinetic growth of B. linanoe cell suspension culture growing in flasks showed an exponential increase up to 9 days of culture time reaching a maximum biomass of 11.16 gDWL-1. During the 12 days of culture, cell viability was maintained between 60-70%. In contrast, when cells were grown in a bioreactor, showed an increase in biomass of 22.26 gDWL-1 on day 7 and cell viability was maintained from 75 to 85%. Using gas chromatography/mass spectrometry, linalool and linalyl acetate were identified in suspension culture.

 

Sulfated Polysaccharides Isolated From Four Green Algae of the Codium Genus and Their Evaluation as Alternative Anticoagulant Drug.

Araceli Rodríguez Cuautle & Jesús Iván Murillo Álvarez

  • Abstract

    Macroalgae have been recognized as a source of bioactive substances; currently have been associated with activity anticoagulant. This property has been the most studied due to the search for new therapeutic options to treat thrombotic and vascular conditions. The aim of the present work was to determine the relationship structure-activity of polysaccharides isolated from aqueous extracts from Codium simulans, C. amplivesciculatum, C. cuneatum and C. fragile. Afterward of ion exchange chromatography over DEAE-cellulose, fraction from C. simulans eluted with sodium chloride 0.5 M significantly increased the I.N.R. (19.9) at 320 μg mL-1. The mid-infrared spectral analysis of the active fraction from C. simulans showed the presence of absorption bands (3400, 2955, 1630, 1400, 1260, 1220, 1100, 1080, 1020, 950 and 820 cm-1) characteristics for sulfated polysaccharides. In contrast, spectra from non-active fractions revealed the absence of absorption bands at 1260 and 820 cm-1 due to vibration of sulfate residues. In conclusion, in this study C. simulans appears to be the most promising source of polysaccharides with anticoagulant activity, which is strongly determined by the presence of sulfate ester residues. The remaining species studied showed just low activity.

 

Antioxidant Activity Associated to Exogenous H2O2 Promotes Ameliorative Effects of Infection by C. Liberibacter in Potato Plants.

Ricardo Martínez, Catalina López., Humberto López.

  • Abstract

    Potato purple top and “Zebra chip” are serious threats to potato production in Mexico; it could be associated to phytoplasma or Candidatus Liberibacter spp. In plant-pathogen relationship, reactive oxygen species like hydrogen peroxide (H2O2) are involved in induction of defense genes, antioxidant enzymes (catalases and peroxidases) promoting tolerance. The aim of this study was to evaluate the effect of exogenous application of H2O2 on the activity of CAT and POX, total chlorophyll and tubers weight in potato plants infected by C. Liberibacter. H2O2 (1mM) was sprayed to potato plants cv. Gigant non-infected and infected under greenhouse conditions. Chlorophyll and enzymatic measurements were determinate at 68 days after transplanting (DAT) and productivity at 83 DAT. At 68 DAT, POX activity was enhanced only in infected plants by H2O2. Interestingly H2O2 treatment increased CAT activity in infected plants. Infected-plants reduced POX activity. Total chlorophyll content was higher in 39.02 % in infected plants sprayed with H2O2 respecting non-infected control plants. Minitubers weight increased by effect of H2O2 from infected-plants (33.8%) respecting to non-infected plants. The highest total chlorophyll content was observed in infected-plants by effect of H2O2 application; which probably induced a higher productivity of minitubers respecting to non-infected control.

 

Isolation Antagonistic Microorganisms For Biological Control Of Pepper Wilt Pathogens

Adriana P. Martínez-Camacho, Talina O. Martínez-Martínez, Juan G. Ángeles-Núñez, Dr. José L. Anaya-López, Dr. Luis A. Mariscal-Amaro

  • Abstract

    Chemical control of wilt pepper caused by Rhizoctonia solani,Fusarium oxysporum,F. solani and Phytophthora capsici caused a continuous and irrational use of site-specific fungicides that provided development of resistant strains. The objective of this research was to isolate and evaluate in vitro the potential soil-borne antagonists for their ability to suppress the growth of R. solani, F. oxysporum, F. solani and P. capsici to improve an efficient alternative. Soil samples of pepper from cropping areas of northern Guanajuato, México, were analyzed to isolated antagonistic microorganisms. These microorganisms were confronted with train of R. solani, F. oxysporum, F. solani and P. capsici isolated from diseased pepper plants. 11 bacteria and 3 fungi (Trichoderma harzianum, Aspergillus parasiticus y Penicillium sp.) strains showed ability to suppress the growth of pathogens (approximately 80%) in vitro conditions. The fungi strains showed greater antagonism in only three days. F. solani and R. solani were the pathogen more susceptible to the antagonism effect. Biological control is an efficient alternative, not only suppresses disease also avoids environmental pollution and increases crop yield.

 

Adventitious Shoot Formation Obtained From In Vitro Culture Of Embryos From Pseudotsuga menziesii Trees Treated With Pesticides

Ana María Guarneros H, Gema L. Galindo-Flores, María Guadalupe Santiago- Martínez, Vidal Guerra-de la Cruz

  • Abstract

    In this research was evaluated the formation of adventitious shoots obtained from in vitro culture of mature embryos from trees of Pseudotsuga menziesii treated with three types and concentrations of pesticides (Thiametoxan 25%, Acephate 97% and Mocotrofos 60%) and two different combinations of plant growth regulators (Naphthalene Acetic Acid/6-Benzyl Aminopurine or 2-4 Dichlorophenoxyacetic Acid/Kinetin). The morphogenetic response of embryos was evaluated in four stages of development. The results showed that the two combinations of plant growth regulators (2-4D/K and ANA/BA) had no effect on morphogenetic response of the embryos. However the seeds treated with Acephate 97% (moderately toxic) had the highest values regarding embryos with morphogenetic response (17.63%), embryos that formed shoots (15.34%) and shoots individualized (19.3), these were of good vigor. Treatments with lower morphogenetic response were those where the seeds were treated with Monocrotophos 60% (highly toxic) with 6.8% of embryos that showed morphogenetic response, 6.18% of embryos that formed shoots and 6.5 shoots individualized. We conclude that the pesticides with greater toxicity as monocotrofos, reduce insect damage to cones and seeds of P. menziesii, but have a toxic effect on reproductive structures affecting the ability of morphogenetic response and shoots development in in vitro conditions

 

Effectiveness of Lecanicillium lecanii for Control of Thrips tabaci Lindeman on Onion Crop.

H. E. Flores-Moctezuma, C. Luna-Gutiérrez and F. Castrejón-Ayala.

  • Abstract

    Fungi entomopathogenic offers an excellent alternative for the conservation of agro-ecological systems. Thrips tabaci reach up to 90% losses in the onion crops in Mexico. The purpose of this study was to evaluate of Lecanicillium lecanii as a bioinsecticide to control T. tabaci Lind. The experiment was made an onion crop located in the community of Santa Ana Necoxtla, San Juan Epatlán; Puebla, Mexico. Two strains of the fungus L. lecanii were provided by the IPI Department, where in previous work dilutions of spores were performed to find the best dose to use in the field. These solutions were sprayed on the leaves where most insects were found. The design was randomized complete block with 2 treatments and a control with 6 replicates each. Experimental (Exp.) plot: 10m, Width (W) x 20m, Length (L); Exp. blocks:11m Lx1m W; Exp. unit 10cm Lx10cm W. After 5 days counting live and dead insects were performed. Analysis of Variance was used at a level of significance α=0.05 and α=0.01 and to establish the differences all procedures with multiple partners (Fisher LSD Method). L. lecanii at concentrations 1×109 ml conidia/100 mortality achieved between 49 and 54% being the most effective concentration under field conditions

 

Baccharis glutinosa L. (Asteraceae) as a Promising Allelophatic Plant to Control Some Pests of Organic Tomato Crop

Mariana Miranda, Guillermo Delgado, Blanca E. Hernández-Bautista, Ricardo Reyes-Chilpa, Martha L. Macías-Rubalcava, and Ana Luisa Anaya

  • Abstract

    Modern agriculture has contributed to the problem of environmental damage by the indiscriminate use of synthetic agrochemicals. This problem has given rise to an extensive effort to find alternative ecological controls of pests, trying to preserve environmental quality and to reach multiple agricultural and organic productions to achieve a sustainable use of natural resources. Allelopathy could be one of the solutions to solve several agricultural problems. Farmers in Tlaxcala, Mexico want to growth organic tomato and asked us to find some natural controls for several of the main diseases and pests of this crop. We were starting the search of several allelopathic plants to deal with some of these diseases and weeds of tomato crop using allelochemicals. Baccharis glutinosa (Asteraceae) was a promising plant with a strong in vitro allelopathic effect on some plants (Amaranthus sp.) and phytopathogenic fungi (Fusarium oxysporum and Phytophthora capsici). These two last species caused crown and root rot to the crop. Aqueous leachates of the dry aerial part significantly inhibited A. hypochondriacus root growth (100%), and mycelia growth of both phytopathogens (50%). Dichloromethane-methanol (CH2Cl2-CH3OH,1:1) extract at 200 μg ml-1 inhibited (40%) the mycelia growth of both phytopathogens. Biodirected chemical fractionation of this organic extract produced some secondary and tertiary fractions with a strong inhibitory effect on mycelia growth of those fungi (83 and 100%), and structural analysis indicated the presence of labdene-type diterpenes. Our results suggest that possibly, a mixture of similar allelopathic compounds of B. glutinosa could be a good precursor of a natural pesticide for an organic production of tomato crop.

 

In Vitro Callus Induction from Root Explants of Ibervillea sonorae

Ilse Y. Arciniega-Carreón, Elena E. Galarza-Ramírez, María del Carmen Oliver-Salvador* and María G. Ramírez-Sotelo

  • Abstract

    The extract obtained from the root of Ibervillea sonorae is used for the treatment of diabetes among other uses, by its hypoglycemic effect. In vitro culture could ensure a constant supply its secondary metabolites with therapeutic properties. In this work was established the callus culture from roots in B5 and MS medium, supplemented with sucrose, vitamins, ascorbic acid, Indole-3-acetic acid (IAA), Naphthalene-1-acetic acid (NAA) and 6-Benzylaminopurine (BAP). Two groups were worked, the first group was maintained in dark and the second in a 16 h photoperiod, both groups were incubated at 22 °C during 15 days. Callus formation was observed around the fifth day and were yellowish to pea-green color. The callus induction was 75 % with the B5 medium and 25% with the MS medium, in a 16 h photoperiod. In the dark, only was achieved a 25 % of callus induction with the MS medium. Comparing the culture conditions, it was determined that a 16 h photoperiod stimulated cell proliferation and the B5 medium more improved the callus growth than the MS medium. B5 medium increased the weight of callus four times and approximately two to three times with MS medium in the first 15 days.

 

Phenolic Compounds of 29 Mexican Varieties of Common Bean (Phaseolus vulgaris L.)

Alfonso Reyes-Martínez, Norma Almaraz-Abarca, Eli Amanda Delgado-Alvarado, Ana Isabel Chaidez-Ayala, José Roberto Medina-Medrano, Hugo Manuel Monreal-García, Marcos Cobaleda-Velasco.

  • Abstract

    Twenty nine Mexican varieties of Phaseolus vulgaris L. were analyzed for their foliar phenol composition in order to determine the importance of leaves of common bean as source of flavonoids and assess the significance of the foliar phenol profiles as typification and authenticity tools to discriminate among cultivars. The variability of foliar phenolic profiles was assessed by HPLC-DAD. A total of 23 phenolic compounds were found (10 quercetin-3-O-glycosides, six kaempferol-3-O-glycosides, six phenolic acid derivatives, and one flavone). Those compounds were accumulated in a typical manner for each variety; this reveals the foliar phenol profiles of Phaseolus vulgaris as important chemical markers for the  etermination of authenticity of varieties. The presence of quercetin and phenolic acids suggests that common bean leaves are important sources of natural antioxidants, while the presence of kaempferol indicates that they are also source of inhibitors of enzyme activities related to human cancer development 

 

Strategy of Bioremediation in Recirculating Aquaculture Systems Using Constructed Microbial Mats

Jorge E. Zamora-Castro, Ricardo Jiménez-Montealegre and Galdy Hernández-Zárate

  • Abstract

    Due to strict international standards, every day there is greater interest in developing  environmentally  sound treatment systems in aquaculture facilities that can remove contaminants from effluent and allows for the reuse of the water. A promising biotechnology is to use microbial mats in recirculating aquaculture systems (RAS). We developed four independents pilot systems (200 L) integrating shrimp culture with microbial mats (two filamentous cyanobacteria, Lyngbya sp. and Anabaena sp., one diatom Chaetoceros sp. and the other of ammonia-oxidizing bacteria and nitrite oxidizing bacterial). The removal percentage of TAN performed by cyanobacteria was about 25%, while Chaetoceros sp. removed 43.5 % in the same time, with a removal rate of 30.22 ± 10.93 g TAN d-1. The algal species present determine the efficiency of the mat; cyanobacteria are often the colonizing, prevailing and dominant group in abundance and diversity, but not necessarily the most efficient for the required bioremediation. The bacterial mats showed high removal efficiencies for nitrogen 82.15% (TAN) and 70.51% of Nitrogen Inorganic Total (NIT). It was concluded that microbial mats are an effective technical strategy to integrate in RAS systems to farm Litopenaeus vannamei due to its metabolic diversity enables the simultaneous absorption, oxidation, and reduction of nutrients. 

 

Effect of Water Exchange and Stocking Density in Development of Shrimp Postlarvae (Litopenaeus Vannamei) Cultured With Biofloc

Gabriela López-Cervantes, Héctor Manuel Esparza-Leal, Píndaro Álvarez-Ruiz

  • Abstract

    Nowadays, some shrimp farmers have implemented nursery systems prior to stocking in ponds, allowing them to have greater control of survival in early stage of the shrimp. The Biofloc technology comprises a complex formation of heterotrophic bacteria, protozoa, algae, metazoan, feces and remains of dead organisms. Hence, the aim of the present study was to evaluate the efficiency of a Biofloc to increase survival and growth of shrimp postlarvae (PL).The experimental design consisted in four treatments: (T1 and T2) 3000 or 6000 PLs/m2 without water exchange. (T3 and T4) 3000 or 6000 PLs/mwith 50% water exchange a week. The Biofloc was activated  supplying molasses as a carbon source (2 g a day). The results showed that T1 was the best treatment (survival >60%). In contrast the treatment 3 was the worst. However, only the T3 showed significant differences against the others. Regarding growth data, the average weight was lower when grown with higher density. In conclusion, the best results were obtained without water changes. The stocking density did not affect the survival and growth, indicating that the culture system is a powerful tool to optimize the space in shrimp nursery.