Differences between Pyrenophora tritici-repentis Isolates in Expression of ToxA and PtrPf2 Genes in Culture (in vitro)

Abstract

For the first time, relative expression levels of the ToxA effector gene and PtrPf2 transcription factor gene in vitro were used to characterize the collection of isolates of the causative agent of tan spot of wheat, Pyrenophora tritici-repentis, from geographically distant populations. It was demonstrated that two groups of isolates, from Kazakhstan (Almaty oblast) and Russia (Krasnodar krai), differed in the levels of genetic diversity. The group of Krasnodar isolates was more heterogenous in expression levels of both genes. In Krasnodar isolates, positive correlation between the expression levels of examined genes was revealed (r = 0.96, p < 0.001). The isolate groups were statistically significantly different in the PtrPf2 expression levels (p = 0.002). According to preliminary data, high virulence of Kazakhstan isolates was associated with high expression levels of the PtrPf2 transcription factor gene in these isolates. A supposition on the existence of association between the PtrPf2 expression level in vitro and the ability of isolates to induce necrosis on the leaves of a susceptible cultivar is made.