Distribution and Frequency to Toxin Producing Genes (ToxA and ToxB) in Populations of Pyrenophora tritici-repentis, the Causal Agent of Wheat Tan Spot in North of Iran

M. Rajabpour,; R. Mehrabi,; M. Torabi,; A. Ebrahimi,

doi:10.22092/spij.2017.111201

Distribution and Frequency to Toxin Producing Genes (ToxA and ToxB) in Populations of Pyrenophora tritici-repentis, the Causal Agent of Wheat Tan Spot in North of Iran

Authors

10.22092/spij.2017.111201

Abstract

The tan spot disease, caused by the fungal wheat pathogen Pyrenophora tritici-repentis, is rapidly spreading in north of Iran due to the high susceptibility of most grown wheat cultivars. The successful use of resistant cultivars depends on sufficient information about the pathogen genetic structure particularly the presence/absence of virulence factors within the fungal populations. The present study was carried out to determine the distribution and frequency of the ToxA and ToxB- producing genes in Iranian fungal population. Wheat samples showing the tan spot symptoms were collected from north of Iran and transferred to laboratory. After fungal isolation, purification and propagation, DNAs from P. tritici-repentis were isolated. The DNA samples were screened using specific primers for detection of ToxA and ToxB genes. The results showed that 86% and 77% of isolates possess ToxA and ToxB genes, respectively, while 64% of isolates possess both virulence factors. Based on these results, most of the tan spot isolates collected from north of Iran contain ToxA and ToxB genes and their distribution in studied isolates were not restricted to specific geographical regions. This study showed that chlorosis and necrosis induced by this pathogen can be attributed to the high frequency of theses genes in the fungal populations..

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