Clone and characterization of a cytochrome P450 gene for drought tolerance in rice

Drought is a major abiotic stress limiting rice production worldwide. Identifying genes that enhance drought tolerance is essential for breeding resilient varieties.

In this study, we report the map-based cloning and functional characterization of DT1, a novel cytochrome P450 gene conferring drought tolerance in rice. Using near isogenic lines (NILs) derived from a cross between Xiang743 and Katy, we delimited DT1 into a 115 kb interval on chromosome 3, where contains 18 open read frames (ORFs). Quantitative real-time polymerase chain reaction (qRT-PCR) analysis identified Os03g55250 as the candidate gene. Clustered regularly interspaced short palindromic repeats-associated nuclease 9 (CRISPR/Cas9) knockout mutants of Os03g55250 exhibited increased drought sensitivity, while overexpression lines showed enhanced drought tolerance, confirming that Os03g55250 was the target gene and positively regulates drought resistance. DT1 was mainly expressed in stems, leaves, and leaf sheaths, and the DT1 protein localized in the endoplasmic reticulum. Haplotype analysis identified Hap1 as a favorable allele in japonica rice.

Our findings provide a promising genetic resource for breeding drought-resistant rice varieties and offers new insights into the role of P450 genes in abiotic stress adaptation.