Natural variation of DROT1 confers drought adaptation in upland rice

Upland rice is a distinct ecotype that grows in aerobic environments and tolerates drought stress. However, the genetic basis of its drought resistance is unclear. Here, using an integrative approach combining a genome-wide association study with analyses of introgression lines and transcriptomic profiles, we identify a gene, DROUGHT1 (DROT1), encoding a COBRA-like protein that confers drought resistance in rice. DROT1 is specifically expressed in vascular bundles and is directly repressed by ERF3 and activated by ERF71, both drought-responsive transcription factors. DROT1 improves drought resistance by adjusting cell wall structure by increasing cellulose content and maintaining cellulose crystallinity. A C-to-T single-nucleotide variation in the promoter increases DROT1 expression and drought resistance in upland rice. The potential elite haplotype of DROT1 in upland rice could originate in wild rice (O. rufipogon) and may be beneficial for breeding upland rice varieties. Genetic basis of the drought tolerance of upland rice is unclear. Here, the authors report the cloning of a COBRA-like protein encoding gene DROT1 and reveal that it is repressed by ERF3 and activated by ERF71 to help control the balance between growth and drought tolerance in upland rice.

Automated summary

This study identifies the DROT1 gene, which encodes a COBRA-like protein, as a key regulator of drought resistance in upland rice. DROT1 is specifically expressed in vascular bundles and is influenced by drought-responsive transcription factors ERF3 and ERF71. The gene enhances drought resistance by adjusting cell wall structure and increasing cellulose content. The findings suggest that a specific single-nucleotide variation in the gene's promoter contributes to improved drought resistance in upland rice.