Drought is a major environmental stress limiting crop yields worldwide. Upland rice (Oryza sativa) has evolved complex genetic mechanisms for adaptative growth under drought stress. However, few genetic variants that mediate drought resistance in upland rice have been identified, and little is known about the evolution of this trait during rice domestication. In this study, using a genome-wide association study we identified ROOT LENGTH 1 (RoLe1) that controls rice root length and drought resistance. We found that a G-to-T polymorphism in the RoLe1 promoter causes increased binding of the transcription factor OsNAC41 and thereby enhanced expression of RoLe1. We further showed that RoLe1 interacts with OsAGAP, an ARF-GTPase activating protein involved in auxin-dependent root development, and interferes with its function to modulate root development. Interestingly, RoLe1 could enhance crop yield by increasing the seed-setting rate under moderate drought conditions. Genomic evolutionary analysis revealed that a newly arisen favorable allelic variant, proRoLe1−526T, originated from the midwest Asia and was retained in upland rice during domestication. Collectively, our study identifies an OsNAC41-RoLe1-OsAGAP module that promotes upland rice root development and drought resistance, providing promising genetic targets for molecular breeding of drought-resistant rice varieties.

中文翻译：

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OsNAC41-RoLe1-OsAGAP 模块促进陆地稻根系发育和抗旱性


干旱是限制全球农作物产量的主要环境压力。陆地稻 （Oryza sativa） 已经进化出在干旱胁迫下适应性生长的复杂遗传机制。然而，目前已鉴定出很少介导陆地稻抗旱性的遗传变异，并且对水稻驯化过程中该性状的演变知之甚少。在这项研究中，我们使用全基因组关联研究确定了控制水稻根长和抗旱性的根长 1 （RoLe1）。我们发现 RoLe1 启动子中的 G-to-T 多态性导致转录因子 OsNAC41 的结合增加，从而增强 RoLe1 的表达。我们进一步表明，RoLe1 与 OsAGAP 相互作用，OsAGAP 是一种参与生长素依赖性根发育的 ARF-GTP 酶激活蛋白，并干扰其调节根发育的功能。有趣的是，RoLe1 可以在中度干旱条件下通过提高结实率来提高作物产量。基因组进化分析显示，新出现的有利等位基因变异 proRoLe1−526T 起源于中西亚，并在驯化过程中保留在陆地稻中。总的来说，我们的研究确定了促进旱稻根系发育和抗旱性的 OsNAC41-RoLe1-OsAGAP 模块，为抗旱水稻品种的分子育种提供了有前途的遗传靶点。