Distribution of races and Tox genes in Pyrenophora tritici-repentis isolates from wheat in Argentina

MORENO M.V., STENGLEIN S.A. & PERELLÓ A.E.

TROPICAL PLANT PATHOLOGY

SOC BRASILEIRA FITOPATHOLOGIA

Año: 2015 vol. 40 p. 141 - 146

1982-5676

Tan spot, caused by Pyrenophora tritici-repentis, is a common disease in the agroecological wheat area of Argentina. In this study 65 isolates of P. tritici-repentis obtained from different cultivars and localities of wheat yield regions of Argentina were analyzed for their virulence on six wheat cultivars or lines (Glenlea, Salomouni,Katepwa, M-3, 6B365 and 6B662) and the presence or absence of the Tox genes based on a PCR approach. Thirty-six isolates could be assigned to races; based onreaction type races 4 and 8 were predominant. The presence or absence of ToxA, ToxB, ToxB-like and toxb genes using PCR specific-primers revealed that 57 isolateshave the fragment corresponding to the ToxA gene whereas only one isolate had the corresponding to ToxA and ToxB genes. No correlation between phenotypic racesand presence or absence of the toxin amplification products was shown. According our results P. tritici-repentis exhibits a complex race structure in Argentina.