Expression of the ToxA and PtrPF2 genes of the phytopathogenic fungus Pyrenophora tritici-repentis at the beginning of the infection process

Abstract

Background. Pyrenophora tritici-repentis causing a tan spot of wheat produces host-specific toxins.
 Materials and methods. Two P. tritici-repentis isolates with different ability to cause necrosis on the leaves of wheat cultivar Glenlea (nec+ and nec) and with different expression level of ToxA and PtrPf2 (factor transcription gene) in vitro were used for analysis. ToxA gene expression in P. tritici-repentis isolates in planta was characterized using quantitative PCR.
 Results. The expression of the ToxA gene in P. tritici-repentis ToxA+ isolates significantly increased when infected the wheat leaves compared to ToxA expression results obtained in vitro. The levels of ToxA expression in both isolates differed significantly after 24, 48 and 96 h after inoculation, however, the dynamics of the trait change over time were similar. However, the highest ToxA expression in the virulent (nec+) isolate in contrast with the avirulent (nec) isolate was observed at a point of 48 h. Whereas the expression of regulating transcription factor PtrPf2 in planta differed imperceptibly from expression in vitro throughout the observation period.
 Conclusion. Obviously, the role of the fungal transcription factor in regulating the effector gene expression weakens in planta, and other mechanisms regulating the expression of pathogen genes at the biotrophic stage of the disease develop.