Sun Lina, Xu Hanqin, Song Juan, Yang Xiaoying, Wang XinYi, Liu Haiyan, Pang Mengzhen, Hu Youchuan, Yang Qi, Ning Xiaotong, Liang Shanshan, Zhang Siju, Luan Weijiang
College of Life Sciences, Tianjin Key Laboratory of Animal and Plant Resistance, Tianjin Normal University, Tianjin, 300387, China.
Rice (N Y). 2024 Feb 15;17(1):15. doi: 10.1186/s12284-024-00690-3.
Leaf senescence, the last stage of leaf development, is essential for crop yield by promoting nutrition relocation from senescence leaves to new leaves and seeds. NAC (NAM/ATAF1/ATAF2/CUC2) proteins, one of the plant-specific transcription factors, widely distribute in plants and play important roles in plant growth and development. Here, we identified a new NAC member OsNAC103 and found that it plays critical roles in leaf senescence and plant architecture in rice. OsNAC103 mRNA levels were dramatically induced by leaf senescence as well as different phytohormones such as ABA, MeJA and ACC and abiotic stresses including dark, drought and high salinity. OsNAC103 acts as a transcription factor with nuclear localization signals at the N terminal and a transcriptional activation signal at the C terminal. Overexpression of OsNAC103 promoted leaf senescence while osnac103 mutants delayed leaf senescence under natural condition and dark-induced condition, meanwhile, senescence-associated genes (SAGs) were up-regulated in OsNAC103 overexpression (OsNAC103-OE) lines, indicating that OsNAC103 positively regulates leaf senescence in rice. Moreover, OsNAC103-OE lines exhibited loose plant architecture with larger tiller angles while tiller angles of osnac103 mutants decreased during the vegetative and reproductive growth stages due to the response of shoot gravitropism, suggesting that OsNAC103 can regulate the plant architecture in rice. Taken together, our results reveal that OsNAC103 plays crucial roles in the regulation of leaf senescence and plant architecture in rice.
叶片衰老作为叶片发育的最后阶段，通过促进营养物质从衰老叶片向新叶和种子的重新分配，对作物产量至关重要。NAC（NAM/ATAF1/ATAF2/CUC2）蛋白是植物特有的转录因子之一，广泛分布于植物中，并在植物生长发育中发挥重要作用。在此，我们鉴定出一个新的NAC成员OsNAC103，并发现它在水稻叶片衰老和株型调控中发挥关键作用。OsNAC103的mRNA水平在叶片衰老以及不同植物激素（如脱落酸、茉莉酸甲酯和乙烯利）和非生物胁迫（包括黑暗、干旱和高盐度）处理下显著上调。OsNAC103作为一种转录因子，在N端具有核定位信号，在C端具有转录激活信号。在自然条件和黑暗诱导条件下，过表达OsNAC103促进叶片衰老，而osnac103突变体延迟叶片衰老，同时衰老相关基因（SAGs）在OsNAC103过表达（OsNAC103-OE）株系中上调，表明OsNAC103正向调控水稻叶片衰老。此外，OsNAC103-OE株系表现出植株结构松散、分蘖角度较大，而osnac103突变体在营养生长和生殖生长阶段由于地上部重力响应导致分蘖角度减小，这表明OsNAC103可以调控水稻的株型。综上所述，我们的结果表明OsNAC103在水稻叶片衰老和株型调控中发挥关键作用。
