Gustavo Hernández-Guzmán

• PhD
• Professor (Associate) at University of Guanajuato

El cempasúchil ( Tagetes erecta ) es una planta asterácea comúnmente utilizada como flor ornamental y ceremonial durante la temporada de otoño en México. Las plantas de cempasúchil cultivadas en el campo presentaron síntomas de la enfermedad de la mancha foliar bacteriana. Se aisló una cepa bacteriana que potencialmente causa la enfermedad de las m...

The most important bioinsecticide used worldwide is Bacillus thuringiensis and its hallmark is a rich variety of insecticidal Cry protein, many of which have been genetically engineered for expression in transgenic crops. Over the past 20 years, the discovery of other insecticidal proteins and metabolites synthesized by B. thuringiensis, including...

The avocado, Persea americana , is a fruit crop of immense importance to Mexican agriculture with an increasing demand worldwide. Avocado lies in the anciently diverged magnoliid clade of angiosperms, which has a controversial phylogenetic position relative to eudicots and monocots. We sequenced the nuclear genomes of the Mexican avocado race, P. a...

The avocado, Persea americana , is a fruit crop of immense importance to Mexican agriculture with an increasing demand worldwide. Avocado lies in the anciently-diverged magnoliid clade of angiosperms, which has a controversial phylogenetic position relative to eudicots and monocots. We sequenced the nuclear genomes of the Mexican avocado race, P. a...

Pseudomonas syringae pv. maculicola (Psm) is a phytopathogen of a wide range of host plants from the cruciferae family, producing blight. Some strains infect Arabidopsis thaliana, whose genetic characteristics has made it a plant model for analyses of different process, such as resistance to phytopathogens. In this study, we have focused on this ba...

Pseudomonas syringae pv. maculicola M2 (Psm) is a phytopathogenic bacteria and one of about 50 pathovars reported in the Pseudomonas syringae group. The host range of Psm included collard, cauliflower, broccoli and others cruciferae plants, producing blight, and among other cruciferae host plants, Arabidopsis thaliana as model study in plant-pathog...

A consolidated two-stage bioprocessing scheme integrates the hydrogen and acetone–butanol–ethanol (ABE) production from wheat straw (WS). In the first stage, hydrogen production was performed from the xylan fraction of native WS with synthetic microbial consortia integrated by epiphytic species of Enterococcus. Three species showed a synergic effec...

Pseudomonas syringae pv. maculicola is a natural pathogen of members of the Brassicaceae plant family. Using a transposon-based mutagenesis strategy in Pseudomonas syringae pv. maculicola M2 (PsmM2), we conducted a genetic screen to identify mutants that were capable of growing in M9 medium supplemented with a crude extract from the leaves of Arabi...

A novel strain of Pectobacterium, isolated from infected sunflower plants (Helianthus annuus L.) in Mexico was characterized. Inoculated sunflower plants developed both tissue chlorosis and soft-rot on leaves. The broad host range shown by this pathogen, which included members of the Agavaceae, Asteraceae, Brassicaceae and Solanaceae, was character...

The cultivated husk tomato (Physalis ixocarpa) (2n = 2x = 24) is native from Mexico and Central America and shows a wide genetic variation. Presently, it is the fourth horticultural crop in cultivation surface in Mexico. The working team of this research previously developed an autotetraploid population by using colchicine. The objectives of the pr...

Bacteriocins synthesized by entomopathogenic Bacillus thuringiensis are gaining attention owing to their inhibitory effects against a wide variety of pathogenic bacteria. In the present study, we purified and characterized Tolworthcin 524, a bacteriocin synthesized by B. thuringiensis subsp. tolworthi, and compared it with other bacteriocins synthe...

The reporter gene cat can be used to determine promoter activation and to seek genes related to pathogenicity, where the promoter becomes tagged. The estimation of promoter expression in these cases can be evaluated by three approaches: i) determination of relative quantity of the mRNA; ii) quantification of protein (chloramphenicol acetyl-transfer...

Bioinformatics analysis and gene expression studies of four clones of guava cDNA encoding for a polygalacturonase (PG), an acid 1-aminocyclopropane-1-carboxylate oxidase (ACCo), and two α-expansins (α-Exp) in guava (Psidium guajava L.), is presented here. Using RT-PCR, a partial cDNA fragment of 301 bp (PgPG1) was associated to a PG from mature fru...

Bioinformatics analysis and gene expression studies of four clones of guava cDNA encoding for a polygalacturonase (PG), an acid 1-aminocyclopropane-1-carboxylate oxidase (ACCo), and two α-expansins (a-Exp) in guava (Psidium guajava L.), is presented here. Using RT-PCR, a partial cDNA fragment of 301 bp (PgPGl) was associated to a PG from mature fru...

It has been argued that the evolution of plant genome size is principally unidirectional and increasing owing to the varied action of whole-genome duplications (WGDs) and mobile element proliferation. However, extreme genome size reductions have been reported in the angiosperm family tree. Here we report the sequence of the 82-megabase genome of th...

The tomatillo, Physalis ixocarpa Brot. (2n = 2x = 24), is an important crop in Mexico, and it is becoming appreciated in other countries. Polyploidy induction is expected to increase its breeding potential. The objective of this work was to develop and characterize tomatillo autotetraploids through colchicine-based induction. Young seedlings of the...

A-Maize-ing Maize is one of our oldest and most important crops, having been domesticated approximately 9000 years ago in central Mexico. Schnable et al. (p. 1112 ; see the cover) present the results of sequencing the B73 inbred maize line. The findings elucidate how maize became diploid after an ancestral doubling of its chromosomes and reveals tr...

The Cuatro Ciénegas Basin (CCB) in the central part of the Chihuahan desert (Coahuila, Mexico) hosts a wide diversity of microorganisms contained within springs thought to be geomorphological relics of an ancient sea. A major question remaining to be answered is whether bacteria from CCB are ancient marine bacteria that adapted to an oligotrophic s...

Pseudomonas syringae pv. phaseolicola is the causal agent of halo blight disease of beans (Phaseolus vulgaris L.), which is characterized by water-soaked lesions surrounded by a chlorotic halo resulting from the action of a non-host-specific toxin known as phaseolotoxin. This phytotoxin inhibits the enzyme ornithine carbamoyltransferase involved in...

Many pathogens are virulent because they specifically interfere with host defense responses and therefore can proliferate. Here, we report that virulent strains of the bacterial phytopathogen Pseudomonas syringae induce systemic susceptibility to secondary P. syringae infection in the host plant Arabidopsis thaliana. This systemic induced susceptib...

To identify Pseudomonas syringae pv. tomato genes involved in pathogenesis, we carried out a screen for Tn5 mutants of P. syringae pv. tomato DC3000 with reduced virulence on Arabidopsis thaliana. Several mutants defining both known and novel virulence loci were identified. Six mutants contained insertions in biosynthetic genes for the phytotoxin c...

Pseudomonas syringae produces the exopolysaccharide alginate, a copolymer of mannuronic and guluronic acid. Although alginate has been isolated from plants infected by P. syringae, the signals and timing of alginate gene expression in planta have not been described. In this study, an algD : : uidA transcriptional fusion, designated pDCalgDP, was co...

Some strains of Pseudomonas fluorescens produce the antibiotic mupirocin, which functions as a competitive inhibitor of isoleucyl-tRNA synthetase (ILERS). Mupirocin-producing strains of P. fluorescens must overcome the inhibitory effects of the antibiotic to avoid self-suicide. However, it is not clear how P. fluorescens protects itself from the to...

Pseudomonas syringae pv. phaseolicola is the causal agent of the "halo blight" disease of beans. A key component in the development of the disease is a nonhost-specific toxin, Ndelta-(N'-sulphodiaminophosphinyl)-ornithyl-alanyl-homoarginine, known as phaseolotoxin. The homoarginine residue in this molecule has been suggested to be the product of L-...

A Tn5-derived mobile element has been constructed to identify genes and promoters related to pathogenesis and virulence in Pseudomonas syringae pv. phaseolicola. To enhance the rate of mutation this Tn5 derivative was constructed carrying a mutant transposase which was placed in cis to the transposable element, but just outside the inverted repeats...

Avocado (Persea americana) is a tropical and subtropical tree species with a center of genetic diversity and domestication in Mesoamerica. The avocado fruit is unique because in contrast to most other fleshy fruits, it accumulates oil instead of sugar giving a high nutritional and industrial value. Avocado has a high content of healthy mono and pol...

Avocado (Persea americana) is a major fruit crop with high nutritional and industrial value. It is one of the rare crop plants among the basal angiosperms that belongs to Lauraceae family. Genomic characterization of avocado will provide an opportunity to examine the developmental genetics of fleshy fruits and some of the mechanisms of early evolut...