Ma Ao, Wang Tian-Jing, Wang Haoran, Guo Peng, Peng Xiaoyuan, Wang Xiaohang, Zhou Ganghua, Liu Wenxin, Zhou Dongxiao, Wang Jie, Xu Zheng-Yi
Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, China.
Plant Cell Rep. 2024 Dec 30;44(1):17. doi: 10.1007/s00299-024-03413-6.
Transcription factor OsGRAS2 regulates salt stress tolerance and yield in rice. Plant-specific GRAS transcription factors are involved in many different aspects of plant growth and development, as well as in biotic and abiotic stress responses, although whether and how they participate in salt stress tolerance in rice (Oryza sativa) remains unclear. A screen of a previously generated set of activation-tagged lines revealed that Activation Tagging Line 63 (AC63) displayed a salt stress-sensitive phenotype. Subsequent thermal asymmetric interlace polymerase chain reaction (TAIL-PCR) showed that AC63 was due to overexpression of OsGRAS2. Ectopic overexpression of OsGRAS2 caused increased salt stress sensitivity, while osgras2 loss-of-function lines displayed salt stress-resistant phenotypes. Further, we observed that OsGRAS2 impacts Na and K ion homeostasis in the shoots. Mutation of OsGRAS2 increased salt tolerance without yield penalty. Phylogenetic tree analysis indicated that OsGRAS2 belonged to the LISCL subfamily of GRAS transcription factors and had high amino acid similarity to OsGRAS23. Both OsGRAS2 and OsGRAS23 underwent homomeric and heteromeric interactions, indicating that they formed homo- and hetero-dimers. Moreover, OsGRAS2 and OsGRAS23 showed transcriptional activation activity that was mostly governed by motif1, which was located at the N-terminal region. Further, we found OsGRAS2 binds to the OsWRKY53 promoter to increase its expression, thereby negatively impacting the OsHKT1;5 expression. This study demonstrates a novel insight into how LISCL subfamily GRAS transcription factors impact salt stress tolerance in rice.
转录因子OsGRAS2调控水稻的耐盐性和产量。植物特有的GRAS转录因子参与植物生长发育的许多不同方面，以及生物和非生物胁迫反应，尽管它们是否以及如何参与水稻（Oryza sativa）的耐盐性仍不清楚。对先前生成的一组激活标签系进行筛选发现，激活标签系63（AC63）表现出盐胁迫敏感表型。随后的热不对称交错聚合酶链反应（TAIL-PCR）表明，AC63是由于OsGRAS2的过表达所致。OsGRAS2的异位过表达导致盐胁迫敏感性增加，而osgras2功能缺失系表现出盐胁迫抗性表型。此外，我们观察到OsGRAS2影响地上部的Na和K离子稳态。OsGRAS2的突变增加了耐盐性且不影响产量。系统发育树分析表明，OsGRAS2属于GRAS转录因子的LISCL亚家族，与OsGRAS23具有较高的氨基酸相似性。OsGRAS2和OsGRAS23均发生同聚和异聚相互作用，表明它们形成了同二聚体和异二聚体。此外，OsGRAS2和OsGRAS23表现出转录激活活性，其活性主要由位于N端区域的基序1决定。此外，我们发现OsGRAS2与OsWRKY53启动子结合以增加其表达，从而对OsHKT1;5的表达产生负面影响。本研究揭示了LISCL亚家族GRAS转录因子如何影响水稻耐盐性的新见解。
