Hunan Province Key Laboratory of Crop Sterile Germplasm Resource Innovation and Application, Hunan Normal University, Changsha, 410081, PR China.
Hunan Province Key Laboratory of Crop Sterile Germplasm Resource Innovation and Application, Hunan Normal University, Changsha, 410081, PR China.
Plant Sci. 2019 Oct;287:110188. doi: 10.1016/j.plantsci.2019.110188. Epub 2019 Jul 13.
9-cis-epoxycarotenoid dioxygenase (NCED) is a rate-limiting enzyme for abscisic acid (ABA) biosynthesis. However, the molecular mechanisms of NCED5 that modulate plant development and abiotic stress tolerance are still unclear, particular in rice. Here, we demonstrate that a rice NCED gene, OsNCED5, was expressed in all tissues we tested, and was induced by exposure to salt stress, water stress, and darkness. Mutational analysis showed that nced5 mutants reduced ABA level and decreased tolerance to salt and water stress and delayed leaf senescence. However, OsNCED5 overexpression increased ABA level, enhanced tolerance to the stresses, and accelerated leaf senescence. Transcript analysis showed that OsNCED5 regulated ABA-dependent abiotic stress and senescence-related gene expression. Additionally, ectopic expression of OsNCED5 tested in Arabidopsis thaliana altered plant size and leaf morphology and delayed seed germination and flowering time. Thus, OsNCED5 may regulate plant development and stress resistance through control of ABA biosynthesis. These findings contribute to our understanding of the molecular mechanisms by which NCED regulates plant development and responses to abiotic stress in different crop species.
9-顺式-环氧类胡萝卜素双加氧酶（NCED）是脱落酸（ABA）生物合成的限速酶。然而，NCED5 调节植物发育和非生物胁迫耐受性的分子机制尚不清楚，特别是在水稻中。在这里，我们证明了一种水稻 NCED 基因 OsNCED5 在我们测试的所有组织中都有表达，并受到盐胁迫、水分胁迫和黑暗的诱导。突变分析表明，nced5 突变体降低了 ABA 水平，降低了对盐和水分胁迫的耐受性，并延迟了叶片衰老。然而，OsNCED5 的过表达增加了 ABA 水平，增强了对胁迫的耐受性，并加速了叶片衰老。转录分析表明，OsNCED5 调节 ABA 依赖的非生物胁迫和衰老相关基因的表达。此外，在拟南芥中异位表达的 OsNCED5 改变了植物的大小和叶片形态，延迟了种子的萌发和开花时间。因此，OsNCED5 可能通过控制 ABA 生物合成来调节植物的发育和对胁迫的抗性。这些发现有助于我们理解 NCED 在不同作物物种中调节植物发育和对非生物胁迫反应的分子机制。
