Pathogenicity Analyses of Rice Blast Fungus () from Rice Area of Northeast China.

In order to understand the pathogenicity differentiation of rice blast fungus ( Cavara), a total of 206 isolates of were collected from three Japonica rice regions in Jilin Province, northeast China. Pathogenicity test showed that the reaction pattern of 25 monogenic differential varieties (MDVs) of rice ( L.) demonstrated a wide pathogenic diversity among the isolates. Those MDVs harbor 23 resistance () genes with the susceptible variety Lijiangxintuanheigu (LTH) as control. Virulent isolates of MDVs harboring genes , , , , , , (two lines), and (two lines) had high frequencies ranging from 80 to 100%, to MDVs harboring genes , (t), , , , , (t), , , and showed intermediate frequencies ranging from 40 to 80%, and to MDVs with genes , (t), (t), (t) and (t) presented low frequencies ranging only from 0 to 40%. The U-i-k-z-ta pattern of race-named criteria categorized the 206 isolates into 175 races. Sub-unit U73 for , i7 for and (t), k177 for //, z17 for (t), and ta332 for (t) were crucial on pathogenic differences in regions. Twenty-seven standard differential blast isolates (SDBIs) were selected to characterize resistance in rice accessions. This study could help to build a durable identification system against blast in the rice area of northeast China and enhance our understanding of the differentiation and diversity of blast races in the world.