OsGRF6-OsYUCCA1/OsWRKY82 Signaling Cascade Upgrade Grain Yield and Bacterial Blight Resistance in Rice.

As a major crop in the world, the sustainable development of rice is often severely restricted by bacterial blight. Breeding crops with resistance is an efficient way to control bacterial blight. However, enhancing resistance often incurs a fitness penalty, making it challenging to simultaneously increase bacterial blight resistance and yield potential. In this study, it is found that OsGRF6, besides being a high-yield gene, can significantly improve rice bacterial blight resistance. Compared with wild-type, the lesion lengths of transgenic material overexpressing OsGRF6 are significantly reduced after inoculation with Xanthomonas oryzae pv. oryzae (Xoo). Furthermore, OsGRF6 can directly bind to the promoters of OsYUCCA1 and OsWRKY82, upregulating their transcription and thereby increasing rice bacterial blight resistance and yield. Haplotypic analysis based on the promoter and genome sequence combined with evolutionary analysis revealed that OsGRF6 is mainly comprised by the OsGRF6(XI) and OsGRF6(GJ) subtypes. The superior haplotype OsGRF6(Hap4) increased its transcriptional activity and contributed to bacterial blight resistance and rice yield. Together, this study provides theoretical support for further revealing the synergistic regulatory mechanism and genetic improvement of rice high yield and bacterial blight resistance, offering a new strategy for developing disease-resistant cultivars.