Variation of Avirulence Genes in the Blast Fungus from Jiangxi Province, China.

The avirulence () genes of are pivotal in eliciting resistance responses in rice, which are mediated by resistance () genes in rice. Monitoring the variation of genes in the pathogen is essential for strategically deploying genes in rice cultivation regions. In this study, a total of 214 isolates were collected from Jiangxi Province, China, in 2022, and the distribution and variation of genes in these isolates were analyzed by PCR amplification and sequencing. The results indicated that , , , and loci were detected in more than 95% of isolates. In addition, the and loci were found in 84.1 and 0.9% of isolates, respectively. Notably, none of the isolates contained the gene. Sequencing results revealed various types of variants, including base replacement, deletion, and insertion, in , , and loci. Moreover, a transposon insertion was identified in the promoter region of . Furthermore, variant isolates were then utilized to inoculate the rice monogenic lines IRBLta-K1, IRBLkm-Ts, IRBLKh-K3, and IRBLb-B. The results demonstrated that the rice monogenic line carrying or was unable to recognize the isolates with the variant or . However, the rice monogenic line with or remained capable of recognizing the isolates with alleles in Jiangxi Province. The information obtained from this study is valuable for breeding blast-resistant rice varieties that will be cultivated in Jiangxi Province, China.