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This study was initiated to understand the evolutionary response of the genetic and virulence str... more This study was initiated to understand the evolutionary response of the genetic and virulence structure of blast populations when subjected to the selection pressure of rice cultivars with resistant, partially resistant, or susceptible reaction to the blast pathogen. Breeding strategies for developing durable blast resistance will be based on the prediction of durability of blast resistance gene combinations identified on
Rice blast, the most important rice disease worldwide can be managed through genetic resistance. ... more Rice blast, the most important rice disease worldwide can be managed through genetic resistance. Continuous monitoring of the evolution leading to important changes in the genetic structure and virulence spectrum of the pathogen is very important for the identification of resistance genes and their combinations to resist those pathogenic changes and preventing resistance breakdown. Understanding this pathogen-host interaction can attain
Folia Microbiologica, 2007
The vacA and cagA genotypes of Helicobacter pylori exhibited distinct geographic distribution and... more The vacA and cagA genotypes of Helicobacter pylori exhibited distinct geographic distribution and correlation with severity of disease. In the above genotypes (obtained from 150 H. pylori-positive patients-139 with gastritis, 10 with ulcer and 1 patient with gastric cancer) combinations vacA s1/m1 and s2/m2 were detected using PCR in 75 and 25 % of isolates, respectively, in patients with chronic gastritis. The of s1/m1 and s2/m2 combinations were also detected from ulcers (60 and 40 %, respectively). The cagA was detected in 30 % of isolates. Concentrated culture supernatants of 7 (64 %) out of 11 H. pylori strains induced vacuolization in Vero cells in titers ranging from 1 : 5 to 1 : 40. The vacA s1 genotype was significantly associated with, but not predictive of the presence of vacuolating cytotoxin activity and the cagA gene.
Go to AGRIS search. Tagging Pi-l(t) gene for blast resistance in rice via linkage to microsatelli... more Go to AGRIS search. Tagging Pi-l(t) gene for blast resistance in rice via linkage to microsatellite markers. ...
The genetic structure of rice blast pathogen populations was studied using 149 and 107 monoconidi... more The genetic structure of rice blast pathogen populations was studied using 149 and 107 monoconidial isolates from Los Palacios and Sur del Jíbaro rice production locations in the western and central regions of Cuba, respectively. These isolates were collected from 35 rice genotypes and total DNA from each isolate was digested with the EcoRI enzyme and probed with a dispersed Magnaporthe grisea repeated sequence (MGR586), which has been widely used in the population analysis of this fungus. MGR586 DNA fingerprinting groups were identified based on DNA restriction fragment length polymorphism similarities. This analysis allowed the identification of 134 haplotypes that were partitioned into four highly related genetic groups. The mean similarity between groups ranged from 75 to 85 %. Group A was predominant in both locations and was composed of 84.7 % of all monoconidial isolations from 33 rice genotypes. Isolates from groups B, C and D were associated with one or a small number of very related varieties in the LP region. Genetic diversity estimates between and within the pathogen collection showed a wider diversity in pathogen populations at the western rice region. This analysis also suggested that the migration of this pathogen could have occurred from the western to central rice regions in Cuba. These results suggested that the specific features of the Cuban fungal populations would be particularly useful for selecting germplasm sources for more durable blast-resistance breeding.
Euphytica, 1999
A survey of the genetic diversity among the major cuban rice cultivars was conducted using isozym... more A survey of the genetic diversity among the major cuban rice cultivars was conducted using isozyme, RAPD and AFLP markers. Polymorphisms were detected for esterases, peroxidases, alcohol dehydrogenases and polyphenoloxidases systems; 21 RAPD primers and four AFLP primer combinations. Heterozygosity arithmetic mean value (Hav(p)), the effective multiplex ratio (EMR) and the marker index (MI), were calculated for isozyme, RAPD and AFLP markers. The mean value of genetic similarity among the different varieties was 0.92 for isozyme, 0.73 for RAPD and 0.58 for AFLP analyses. Thus, AFLP were able to detect polymorphisms with higher efficiency than RAPD (+15%) and isozyme (+34%). Data from the isozyme, RAPD and AFLP analyses were used to compute matrices of genetic similarities. The efficiency of the UPGMA for the estimation of genetic relatedness among varieties was supported by cophenetic correlation coefficients. The resulting values indicated that the distortion level for the estimate...
This study was initiated to understand the evolutionary response of the genetic and virulence str... more This study was initiated to understand the evolutionary response of the genetic and virulence structure of blast populations when subjected to the selection pressure of rice cultivars with resistant, partially resistant, or susceptible reaction to the blast pathogen. Breeding strategies for developing durable blast resistance will be based on the prediction of durability of blast resistance gene combinations identified on
Rice blast, the most important rice disease worldwide can be managed through genetic resistance. ... more Rice blast, the most important rice disease worldwide can be managed through genetic resistance. Continuous monitoring of the evolution leading to important changes in the genetic structure and virulence spectrum of the pathogen is very important for the identification of resistance genes and their combinations to resist those pathogenic changes and preventing resistance breakdown. Understanding this pathogen-host interaction can attain
Folia Microbiologica, 2007
The vacA and cagA genotypes of Helicobacter pylori exhibited distinct geographic distribution and... more The vacA and cagA genotypes of Helicobacter pylori exhibited distinct geographic distribution and correlation with severity of disease. In the above genotypes (obtained from 150 H. pylori-positive patients-139 with gastritis, 10 with ulcer and 1 patient with gastric cancer) combinations vacA s1/m1 and s2/m2 were detected using PCR in 75 and 25 % of isolates, respectively, in patients with chronic gastritis. The of s1/m1 and s2/m2 combinations were also detected from ulcers (60 and 40 %, respectively). The cagA was detected in 30 % of isolates. Concentrated culture supernatants of 7 (64 %) out of 11 H. pylori strains induced vacuolization in Vero cells in titers ranging from 1 : 5 to 1 : 40. The vacA s1 genotype was significantly associated with, but not predictive of the presence of vacuolating cytotoxin activity and the cagA gene.
Go to AGRIS search. Tagging Pi-l(t) gene for blast resistance in rice via linkage to microsatelli... more Go to AGRIS search. Tagging Pi-l(t) gene for blast resistance in rice via linkage to microsatellite markers. ...
The genetic structure of rice blast pathogen populations was studied using 149 and 107 monoconidi... more The genetic structure of rice blast pathogen populations was studied using 149 and 107 monoconidial isolates from Los Palacios and Sur del Jíbaro rice production locations in the western and central regions of Cuba, respectively. These isolates were collected from 35 rice genotypes and total DNA from each isolate was digested with the EcoRI enzyme and probed with a dispersed Magnaporthe grisea repeated sequence (MGR586), which has been widely used in the population analysis of this fungus. MGR586 DNA fingerprinting groups were identified based on DNA restriction fragment length polymorphism similarities. This analysis allowed the identification of 134 haplotypes that were partitioned into four highly related genetic groups. The mean similarity between groups ranged from 75 to 85 %. Group A was predominant in both locations and was composed of 84.7 % of all monoconidial isolations from 33 rice genotypes. Isolates from groups B, C and D were associated with one or a small number of very related varieties in the LP region. Genetic diversity estimates between and within the pathogen collection showed a wider diversity in pathogen populations at the western rice region. This analysis also suggested that the migration of this pathogen could have occurred from the western to central rice regions in Cuba. These results suggested that the specific features of the Cuban fungal populations would be particularly useful for selecting germplasm sources for more durable blast-resistance breeding.
Euphytica, 1999
A survey of the genetic diversity among the major cuban rice cultivars was conducted using isozym... more A survey of the genetic diversity among the major cuban rice cultivars was conducted using isozyme, RAPD and AFLP markers. Polymorphisms were detected for esterases, peroxidases, alcohol dehydrogenases and polyphenoloxidases systems; 21 RAPD primers and four AFLP primer combinations. Heterozygosity arithmetic mean value (Hav(p)), the effective multiplex ratio (EMR) and the marker index (MI), were calculated for isozyme, RAPD and AFLP markers. The mean value of genetic similarity among the different varieties was 0.92 for isozyme, 0.73 for RAPD and 0.58 for AFLP analyses. Thus, AFLP were able to detect polymorphisms with higher efficiency than RAPD (+15%) and isozyme (+34%). Data from the isozyme, RAPD and AFLP analyses were used to compute matrices of genetic similarities. The efficiency of the UPGMA for the estimation of genetic relatedness among varieties was supported by cophenetic correlation coefficients. The resulting values indicated that the distortion level for the estimate...