Natural Variation in <i>OsLG3</i> Increases Drought Tolerance in Rice by Inducing ROS Scavenging

Abstract

Improving the performance of rice (<i>Oryza sativa</i>) under drought stress has the potential to significantly affect rice productivity. Here, we report that the ERF family transcription factor OsLG3 positively regulates drought tolerance in rice. In our previous work, we found that <i>OsLG3</i> has a positive effect on rice grain length without affecting grain quality. In this study, we found that <i>OsLG3</i> was more strongly expressed in upland rice than in lowland rice under drought stress conditions. By performing candidate gene association analysis, we found that natural variation in the promoter of <i>OsLG3</i> is associated with tolerance to osmotic stress in germinating rice seeds. Overexpression of <i>OsLG3</i> significantly improved the tolerance of rice plants to simulated drought, whereas suppression of <i>OsLG3</i> resulted in greater susceptibility. Phylogenetic analysis indicated that the tolerant allele of <i>OsLG3</i> may improve drought tolerance in cultivated <i>japonica</i> rice. Introgression lines and complementation transgenic lines containing the elite allele of <i>OsLG3</i>^IRAT109 showed increased drought tolerance, demonstrating that natural variation in <i>OsLG3</i> contributes to drought tolerance in rice. Further investigation suggested that <i>OsLG3</i> plays a positive role in drought stress tolerance in rice by inducing reactive oxygen species scavenging. Collectively, our findings reveal that natural variation in <i>OsLG3</i> contributes to rice drought tolerance and that the elite allele of <i>OsLG3</i> is a promising genetic resource for the development of drought-tolerant rice varieties.