Author: Blondy Beatriz Canto Canché
BLONDY BEATRIZ CANTO CANCHE (2000)
BLONDY BEATRIZ CANTO CANCHE (2013)
The hemibiotropic fungus Mycosphaerella fijiensis is the causal agent of black Sygatoka, the most devastating foliar disease in banana worldwide.
BLONDY BEATRIZ CANTO CANCHE (2013)
Bacteria oxidize organic matter and nutrients to produce
electric energy in microbial fuel cells (MFC) - a technology of increasing
importance because of its sustainability. To improve the performance
of MFCs, it is necessary not only to gain a better understanding of
MFC engineering designs, but also to improve the understanding of
the composition of the microbial communities in MFCs. Fast and
efficient DNA extraction protocols that are suitable for extracting
diverse bacterial genomes are necessary to identify the bacterial
diversity present in MFCs and to further monitor the dynamic changes
of microbial communities. This study focused on testing different direct
cell lysis protocols to extract DNA from a microbial sludge harvested from an MFC. The protocol that achieved the best results was based on
a previous study, but was modified by eliminating a chaotropic salt and
the special columns used for nucleic acid purification. The efficiency of
this less expensive and more straightforward protocol was confirmed
by PCR amplification of the 16S rRNA gene and denaturing gradient
gel electrophoresis analysis, which confirmed the extraction of multiple
genomes. The sequences of 10 clones revealed the presence of phyla,
Proteobacteria, Firmicutes and Actinobacteria, comprising both Gramnegative
and Gram-positive bacteria. Some of these bacteria were
identified at the genus level, e.g., Clostridium, Pseudoxanthomonas,
Tistrella, and Enterobacter; these genera have been described in active
sludges from wastewater treatment, supporting the congruency of
our results. Therefore, this protocol is a useful tool for analysis of the
bacteria responsible for energy production in MFCs.
The plant-pathogenic fungus Mycosphaerella graminicola (asexual stage: Septoria tritici) causes septoria tritici blotch, a disease that greatly reduces the yield and quality of wheat. This disease is economically important in most wheat-growing areas worldwide and threatens global food production. Control of the disease has been hampered by a limited understanding of the genetic and biochemical bases of pathogenicity, including mechanisms of infection and of resistance in the host. Unlike most other plant pathogens, M. graminicola has a long latent period during which it evades host defenses. Although this type of stealth pathogenicity occurs commonly in Mycosphaerella and other Dothideomycetes, the largest class of plant-pathogenic fungi, its genetic basis is not known. To address this problem, the genome of M. graminicola was sequenced completely. The finished genome contains 21 chromosomes, eight of which could be lost with no visible effect on the fungus and thus are dispensable. This eight-chromosome dispensome is dynamic in field and progeny isolates, is different from the core genome in gene and repeat content, and appears to have originated by ancient horizontal transfer from an unknown donor. Synteny plots of the M. graminicola chromosomes versus those of the only other sequenced Dothideomycete, Stagonospora nodorum, revealed conservation of gene content but not order or orientation, suggesting a high rate of intra-chromosomal rearrangement in one or both species. This observed "mesosynteny" is very different from synteny seen between other organisms. A surprising feature of the M. graminicola genome compared to other sequenced plant pathogens was that it contained very few genes for enzymes that break down plant cell walls, which was more similar to endophytes than to pathogens. The stealth pathogenesis of M. graminicola probably involves degradation of proteins rather than carbohydrates to evade host defenses during the biotrophic stage of infection and may have evolved from endophytic ancestors.
To obtain basic information about the regulation of the enzyme geraniol 10-hydroxylase, the behavior of this enzyme and its redox partner –the NADPH: Cyt C (P450) reductase- was examined in C. roseus hairy roots subjected to various treatments. For several of these treatments, no concerted responses of either enzyme were observed, but in general, reductase was more responsive than G10H. The possible meaning of this finding is discussed.
Idiomorphs mat1-1 and mat1-2 from Mycosphaerella fijiensis, the causal agent of black leaf streak disease of banana, were isolated. Degenerate oligos were used to amplify the HMG box of themat1-2 idiomorph from M. fijiensis, showing homology with the HMG box of Mycosphaerella graminicola. Using a DNA walking strategy, anchored on the DNA lyase gene towards the HMG box, a 9-kb-long region of mat1-2 was obtained. A 5-kb fragment from the mat1-1 region was obtained by long-range PCR using primers on the flanking regions, which have close to 100% identity between both idiomorphs. High-identity (77-89%), inverted regions within both idiomorphs were found, which suggest unique inversion events, which have not been found before, and that could have been significant in the evolution of this species. The predicted genes showed the conserved introns in both idiomorphs as well as an additional intron within the alpha box. The implications for theevolution of species in the Mycosphaerella complex on banana are discussed.
Pathogens are able to deliver small-secreted, cysteine-rich proteins into plant cells to enable infection. The computational prediction of effector proteins remains one of the most challenging areas in the study of plant fungi interactions. At present, there are several bioinformatic programs that can help in the identification of these proteins; however, in most cases, these programs are managed independently. Here, we present EffHunter, an easy and fast bioinformatics tool for the identification of effectors. This predictor was used to identify putative effectors in 88 proteomes using characteristics such as size, cysteine residue content, secretion signal and transmembrane domains.
COMPUTATIONAL PREDICTION HOST-PATHOGEN INTERACTION EFFECTOR PROTEINS FUNGAL SECRETOME BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOLOGÍA MOLECULAR BIOLOGÍA MOLECULAR DE PLANTAS BIOLOGÍA MOLECULAR DE PLANTAS
Martín Antonio Pablo Moreno Pérez MARIA MARCELA GAMBOA ANGULO GABRIELA PATRICIA HEREDIA ABARCA Blondy Beatriz Canto Canché MIGUEL ENRIQUE ROSADO VALLADO Irma Leticia Medina Baizabal RAUL TAPIA TUSSELL (2014)
In the search for natural alternatives to control fungal diseases, antagonistic fungi are valuable sources to find new models. In the present study, a total of 41 tropical micromycetes were isolated from plant debris submerged in sinkholes of the Yucatán Península. All strains were tested in antagonist assays against four phytopathogenic fungi (Colletotrichum gloeosporioides, Corynespora cassiicola, Curvularia sp. and Fusarium sp.). Results of the antagonistic assays showed mycelial growth inhibition (MCI ≥50 %) by 17 isolates (41 %) against at least one of the targets tested. The highest inhibition was exhibited by the Hypocrea lixii OSN-37 (MCI=61-77%) and Rhizoctonia solani OSE-73 (MCI=55-64%) strains against all targets while Pestalotiopsis mangiferae OH-02 (51-59%) caused inhibition on three of four pathogen strains. These three strains were cultured in fermented rice to obtain their ethyl acetate and methanol extracts which were tested against C. gloeosporioides using the microdilution assay. Results showed H. lixii OSN-37 and R. solani OSE-73 to be producers of antifungal metabolites as one of their modes of action. In conclusion, three promising antagonistic native strains were isolated from plant debris submerged in the Yucatán sinkholes, representing a valuable contribution to the development of ecofriendly alternatives to control fungal diseases in agriculture crops of the tropical regions.
ALAN RODRIGO LOPEZ ROSALES Katia Ancona Canché JUAN CARLOS CHAVARRIA HERNANDEZ Luis Felipe Barahona Pérez Tanit Toledano Thompson GLORIA GARDUÑO SOLORZANO Silvia López Adrian Blondy Beatriz Canto Canché ERIK MANUEL DE ATOCHA POLANCO LUGO RUBY ALEJANDRA VALDEZ OJEDA (2019)
Marine microalgae are a promising feedstock for biofuel production given their high growth rates and biomass production together with cost reductions due to the use of seawater for culture preparation. However, different microalgae species produce different families of compounds. Some compounds could be used directly as fuels, while others require thermochemical processing to obtain quality biofuels. This work focuses on the characterization of three marine microalgae strains native in Mexico and reported for the first time. Ultrastructure and phylogenetic analysis, suggested that they belong to Nannochloropsis sp. (NSRE-1 and NSRE-2) and Nannochloris sp. (NRRE-1). The composition of their lipid fractions included hydrocarbons, triacylglycerides (TAGs), free fatty acids (FFAs) and terpenes. Based on theoretical estimations from TAG and FFA composition, the potential biodiesels were found to comply with six of the seven estimated properties (ASTM D6751 and EN 14214). On the other hand, hydrocarbons and terpenes synthesized by the strains have outstanding potential as precursors for the production of other renewable fuels, mainly green diesel and bio-jet fuel, which are “drop-in” fuels with quality properties similar to fossil fuels. The validity of this theoretical analysis was demonstrated for the oxygenates of strain NSRE-2, which were experimentally hydrodeoxygenated, obtaining a high-quality renewable diesel as the reaction product.
Black Sigatoka is a disease that occurs in banana plantations worldwide. This disease is caused by the hemibiotrophic fungus Pseudocercospora fijiensis, whose infection results in a significant reduction in both product quality and yield. Therefore, detection and identification in the early stages of this pathogen in plants could help minimize losses, as well as prevent the spread of the disease to neighboring cultures. To achieve this, a highly sensitive SPR immunosensor was developed to detect P. fijiensis in real samples of leaf extracts in early stages of the disease. A polyclonal antibody (anti-HF1), produced against HF1 (cell wall protein of P. fijiensis) was covalently immobilized on a gold-coated chip via a mixed self-assembled monolayer (SAM) of alkanethiols using the EDC/NHS method. The analytical parameters of the biosensor were established, obtaining a limit of detection of 11.7 µg mL−1, a sensitivity of 0.0021 units of reflectance per ng mL−1 and a linear response range for the antigen from 39.1 to 122 µg mL−1. No matrix effects were observed during the measurements of real leaf banana extracts by the immunosensor. To the best of our knowledge, this is the first research into the development of an SPR biosensor for the detection of P. fijiensis, which demonstrates its potential as an alternative analytical tool for in-field monitoring of black Sigatoka disease.