Genetic diversity and pathogenicity dynamics of Magnaporthe oryzae in the Wuling Mountain area of China

Rice blast, caused by Magnaporthe oryzae (M. oryzae), is one of the most destructive diseases in cultivated rice. The Wuling Mountain Area is marked as the key area for the national prevention and control of rice blast disease in China and is the ideal area for M. oryzae research according to its unique natural condition. In this study, a simple, low-cost and effective marker system including RAPD, REMAP, rep-PCR and Avr genes was developed for genetic diversity analysis of 108 M. oryzae isolates collected from the Wuling Mountain Area during 2012–2014. The results showed significant changes in the genetic structures of M. oryzae populations over the 3 years. However, there was no remarkably simple relationship between the genetic lineages and pathotypes (physiological races) of M. oryzae. The main mechanisms of M. oryzae to overcome host genes in the natural conditions of the Wuling Mountain Area might be point mutations or small deletions of gene sequences.