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

Abstract

The genetic structure and diversity of <i>Mycosphaerella graminicola</i> population were studied with ISSR molecular markers, using isolates from several locations of the Argentinean wheat region: subregion IV (SE of Buenos Aires Province) and II South (central part of Buenos Aires Province). Samples were taken from different bread wheat (<i>Triticum aestivum</i>) cultivars. A total of 126 isolates were subjected to molecular analysis to compare the genetic structure of the isolates from both wheat subregions. Ten ISSR primers were used: (GACA)₄; (AAC)₇; (ATC)₇; (AC)₉; (AAG)₇; (AG)₉; (AGC)₅; (CAG)₅, (GTG)₅ and (GACAC)₃. Eighty-four bands ranging from 200 bp to 8.000 were amplified. Eighty-one distinct haplotypes were identified and 43 isolates did not generate any amplification products. The highest number of polymorphic DNA fragments were produced using ISSR primers (ATC)₇ and (GTG)₅, which detected bands in 38 isolates. The molecular analysis revealed the existence of 81 different haplotypes among the 126 isolates studied. These results revealed a high degree of genetic diversity in the <i>M. graminicola</i> population in Argentina.