Transcriptome Analysis and Functional Identification of Xa13 and Pi‐ta Orthologs in Oryza granulata

Core Ideas These 91,562 high‐quality transcripts of Oryza granulata provide an important resource for functional and evolutionary studies in Oryza. O. granulata and Oryza meyeriana have been subjected to adaptive evolution and developed unique gene resources for scientific research and breeding. OgPi‐ta can increase resistance to rice blast and may play roles in plant defenses against various environmental stresses. Oryza granulata Nees & Arn. ex Watt, a perennial wild rice species with a GG genome, preserves many important genes for cultivated rice (Oryza sativa L.) improvement. At present, however, no genetic resource is available for studying O. granulata. Here, we report 91,562 high‐quality transcripts of O. granulata assembled de novo. Moreover, comparative transcriptome analysis revealed that 1311 single‐copy orthologous pairs shared by O. granulata and Oryza meyeriana (Zoll. & Moritzi) Baill. that may have undergone adaptive evolution. We performed an analysis of the genes potentially involved in plant–pathogen interactions to explore the molecular basis of disease resistance, and isolated the full‐length cDNAs of Xa13 (OgXa13) and Pi‐ta (OgPi‐ta) orthologs from O. granulata. The overexpression of OgPi‐ta in Nipponbare and functional characterization showed enhanced the resistance of transgenic Nipponbare to rice blast resulting from the presence of the OgPi‐ta gene. OgPi‐ta, an alternatively spliced transcript of the Pi‐ta blast resistance gene in O. sativa, encodes a 1024‐amino acid polypeptide with a C‐terminal thioredoxin domain. This study provides an important resource for functional and evolutionary studies of the genus Oryza.