Cloning of Pid2 Homolog from Oryza officinalis and Functional Analysis of Rice Blast Resistance in Transgenic Yunjing 37 Lines

Rice blast, caused by the fungus Magnaporthe oryzae, is one of the most devastating threatening to global rice production. The narrow genetic background of modern rice cultivars exacerbates the shortage of durable resistance resources. In contrast, the wild rice species Oryza officinalis harbors abundant stress-resistance alleles and represents a valuable gene pool for identifying novel broad blast-resistance genes. The cloned resistance gene Pid2 is encoded in a receptor-like protein kinase conferring race-specific resistance against the M. oryzae isolate ZB15. In this study, three Pid2 homologs were isolated from O. officinalis. The special allele Pid2of-MD33 was transformed into “Yunjing 37(YG37), a blast-susceptible japonica rice cultivar” via Agrobacterium-mediated transformation. Quantitative real-time PCR analysis showed that Pid2of-MD33 was consistently expressed in various tissues of O. officinalis, with the highest transcript abundance detected in leaf mesophyll cells and plasma membranes. Inoculation with the M. oryzae isolate ZB15 revealed that transgenic YG37 lines expressing Pid2of-MD33 displayed significantly reduced lesion size and pathogen proliferation, suggesting recovered race-specific resistance. These results enrich the resistance gene resources for rice blast research and provide a promising candidate gene for rice blast resistance breeding.