Natural variation of *DROT1* confers drought adaptation in upland rice

Upland rice, an ecotype thriving in aerobic conditions and exhibiting drought tolerance, has an unclear genetic basis for its resistance. This study utilized a genome-wide association study (GWAS) combined with introgression line and transcriptomic analyses to identify *DROUGHT1* (*DROT1*), a gene encoding a COBRA-like protein that enhances drought resistance. *DROT1*, expressed in vascular bundles, is repressed by ERF3 and activated by ERF71, both drought-responsive transcription factors. It improves drought resistance by modulating cell wall structure, increasing cellulose content and maintaining cellulose crystallinity. A C-to-T single-nucleotide variation in the promoter boosts *DROT1* expression and drought resistance. The elite *DROT1* haplotype in upland rice possibly originated from wild rice (*O. rufipogon*) and could benefit upland rice breeding.

Xingming Sun, Haiyan Xiong, Conghui Jiang, Dongmei Zhang, Zengling Yang, Yuanping Huang, Wanbin Zhu, Shuaishuai Ma, Junzhi Duan, Xin Wang, Wei Liu, Haifeng Guo, Gangling Li, Jiawei Qi, Chaobo Liang, Zhanying Zhang, Jinjie Li, Hongliang Zhang, Lujia Han, Yihua Zhou, Youliang Peng, Zichao Li