Genetic Structure of Mycosphaerella graminicola Populations from Iran, Argentina and Australia

Abstract

Restriction fragment length polymorphism (RFLP) markers were used to assess the genetic structure of populations of Mycosphaerella graminicola collected from wheat fields. A total of 585 isolates representing 10 field populations were sampled from Iran, Argentina and Australia. The genetic structure of M. graminicola populations from Iran and Argentina is described for the first time. Results were compared to previously investigated populations from Israel, Uruguay and Australia. Populations from Iran exhibited high clonality and low gene diversity, suggesting an inoculation event. Populations from uninoculated fields in Argentina had gene and genotype diversities similar to previously described European and North American populations. Genotype diversity was high for populations from Australia and tests for multilocus associations were consistent with sexual recombination in these populations. Gene diversity was low and fixed alleles were found for several loci. These findings are consistent with a relatively small founding population for Australia. These 10 new populations were integrated into a genetic distance comparison with 13 global populations that were characterized earlier.

Molecular variability among isolates of Mycosphaerella graminicola, the causal agent of septoria tritici blotch, in Argentina

“…Necochea 50 and 52 Tres Arroyos 202,226,228,229,232,236,237,238,249,255,260 Our analysis showed that there was higher genotype diversity in the population from wheat subregion IV than in that from subregion II South. Our results are in agreement with those of Jürgens et al (2006) and Cordo et al (2006), who found different rates of genotype diversity when comparing populations in Argentina using RFLP. Jürgens et al (2006) studied five populations from three different locations: Los Hornos (ARG1 and ARG5), Balcarce (ARG2) and Barrow (ARG3 and ARG4), and found that 65% of all isolates were unique genotypes.…”

“…Our results are in agreement with those of Jürgens et al (2006) and Cordo et al (2006), who found different rates of genotype diversity when comparing populations in Argentina using RFLP. Jürgens et al (2006) studied five populations from three different locations: Los Hornos (ARG1 and ARG5), Balcarce (ARG2) and Barrow (ARG3 and ARG4), and found that 65% of all isolates were unique genotypes. Likewise, Cordo et al (2006) studied the populations from Balcarce (subregion IV) and Los Hornos (subregion II South), and found 39 genotypes among 62 isolates of the pathogen in Balcarce and 35 unique genotypes among a total of 58 isolates in Los Hornos.…”

“…Furthermore, it is necessary to take into account that isolates for both subregions were randomly taken from all the commercial cultivars in different years, which could have added more variation between the subregions. Jürgens et al (2006) also found that the Argentinean populations ARG1, ARG2 and ARG3 differed significantly in genotype diversity.…”

“…Using RFLP, Jürgens et al (2006) compared five populations from Los Hornos, Balcarce and Barrow (all in the Province of Buenos Aires) and determined that the populations from uninoculated fields in Argentina had higher gene and genotype diversities than those from inoculated fields. However, knowledge of the extent of the genetic diversity and of how the pathogen population may vary in different subregions in Argentina is still lacking.…”

Caractérisation morpho-culturale et sporulation chez une population marocaine de <i>Septoria tritici</i>, agent de la septoriose du blé

“…Ces processus fournissent de nouvelles combinaisons de virulence à l'intérieur de la population du pathogène. Buxton (1960) et Osbumet al, (1987 (Boegeret al, 1993;Chen et al, 1994;McDonald et al, 1996;Cristina et al, 1997;Zhan et al, 2003;Jurgens et al, 2006). Cette dernière est mise en évidence par utilisation des techniques de marquage moléculaire (PCR, RAPD, AFLP, FRLP, SSR…...).…”