Zhao Zhe, Xie Yuelan, Tian Mengqing, Liu Jinzhao, Chen Chun, Zhou Jiyong, Guo Tao, Xiao Wuming
National Engineering Research Center of Plant Space Breeding, South China Agricultural University, Guangzhou 510642, China.
Yangjiang Institute of Agricultural Sciences, Yangjiang 529500, China.
Plants (Basel). 2024 Sep 17;13(18):2593. doi: 10.3390/plants13182593.
Submergence stress challenges direct seeding in rice cultivation. In this study, we identified a heat shock protein, , with a DnaJ domain, which can regulate the length of rice coleoptiles under flooded conditions. Through bioinformatics analyses, we identified -regulatory elements in its promoter, making it responsive to abiotic stresses, such as hypoxia or anoxia. Expression of was higher in the basal regions of shoots and coleoptiles during flooding. knockout triggered the rapid accumulation of abscisic acid (ABA) and reduction of Gibberellin (GA), stimulating rice coleoptile elongation and contributes to flooding stress management. In addition, mutants were found to be more sensitive to ABA treatments. Such knockout lines exhibited enhanced cell elongation for coleoptile extension. Quantitative RT-PCR analysis revealed that mediated the gluconeogenic pathway, essential for the energy needed in cell expansion. Furthermore, mutants reduced the accumulation of reactive oxygen species (ROS) and malondialdehyde under submerged stress, attributed to an improved antioxidant enzyme system compared to the wild-type. In conclusion, our findings underscore the pivotal role of knockout in enhancing the tolerance of rice to submergence stress by elucidating its mechanisms. This insight offers a new strategy for improving resilience against flooding in rice cultivation.
淹水胁迫对水稻直播构成挑战。在本研究中，我们鉴定出一种具有DnaJ结构域的热休克蛋白，其可在淹水条件下调节水稻胚芽鞘的长度。通过生物信息学分析，我们在其启动子中鉴定出调控元件，使其对缺氧或无氧等非生物胁迫产生响应。淹水期间，该蛋白在茎和胚芽鞘的基部区域表达较高。该蛋白敲除会触发脱落酸（ABA）的快速积累和赤霉素（GA）的减少，刺激水稻胚芽鞘伸长，有助于应对淹水胁迫。此外，发现该蛋白突变体对ABA处理更敏感。此类敲除系表现出胚芽鞘伸长的细胞伸长增强。定量RT-PCR分析表明，该蛋白介导了糖异生途径，这对细胞扩张所需的能量至关重要。此外，与野生型相比，该蛋白突变体在淹水胁迫下减少了活性氧（ROS）和丙二醛的积累，这归因于抗氧化酶系统的改善。总之，我们的研究结果通过阐明其机制强调了该蛋白敲除在增强水稻对淹水胁迫耐受性方面的关键作用。这一见解为提高水稻种植中抗淹能力提供了新策略。
