Wang Jie, Xu Weibiao, Long Weixiong, Luo Lihua, Chen Wei, Luo Laiyang, Li Yonghui, Cai Yaohui, Xie Hongwei
Jiangxi Super-Rice Research and Development Center, Jiangxi Academy of Agricultural Sciences, Jiangxi Provincial Key Laboratory of Rice Germplasm Innovation and Breeding, National Engineering Research Center for Rice, Nanchang 330200, China.
Jiangxi Super-Rice Research and Development Center, Jiangxi Academy of Agricultural Sciences, Jiangxi Provincial Key Laboratory of Rice Germplasm Innovation and Breeding, National Engineering Research Center for Rice, Nanchang 330200, China.
Int J Biol Macromol. 2025 Sep;321(Pt 4):146549. doi: 10.1016/j.ijbiomac.2025.146549. Epub 2025 Aug 6.
Rice yield is significantly impacted by elevated temperatures and heat damage, making it crucial to identify heat stress response genes and analyze their molecular mechanisms. In this study, we obtained a temperature-sensitive mutant, ts12, by screening an indica restorer line, R225 (wild type, WT), which was mutated through γ-ray irradiation. In the ts12 mutant, the glume fails to close properly under high-temperature conditions, resulting in a substantial reduction in the seed-setting ratio and grain yield. Cytological observations revealed that the reduction in transverse cell layers and the shortening of cell length contribute to the open glume phenotype in ts12. Map-based cloning and transgenic complementation studies indicated that TS12 encodes the ascorbate peroxidase OsAPX5, with a single nucleotide polymorphism (SNP) in ts12 leading to a truncated OsAPX5 protein. Furthermore, OsAPX5 was found to be widely expressed in the root, stem, leaf sheath, and young panicles, with its protein localized in the mitochondrion. Under high-temperature conditions, the ts12 mutant accumulates a higher concentration of reactive oxygen species (ROS) compared to the wild type (WT). Through yeast two-hybrid, luciferase, and pull-down assays, we demonstrated that OsAPX5 interacts with the rice glume development regulator OsMADS1. Additionally, the expression levels of OsMADS1, OsMADS5, and OsMADS34, which are associated with glume development, were significantly decreased in ts12 compared to the WT. Moreover, the OsAPX5-OsMADS1 interaction promoted the transcriptional activity of OsMADS1 and OsMADS34. These results indicate that OsAPX5 primarily influences ROS levels and the expression of OsMADS1, OsMADS5, and OsMADS34, thereby regulating the high-temperature stress response in rice.
水稻产量受到气温升高和热害的显著影响，因此鉴定热应激反应基因并分析其分子机制至关重要。在本研究中，我们通过筛选经γ射线辐照诱变的籼稻恢复系R225（野生型，WT）获得了一个温度敏感型突变体ts12。在ts12突变体中，颖壳在高温条件下无法正常闭合，导致结实率和籽粒产量大幅降低。细胞学观察表明，横向细胞层数减少和细胞长度缩短导致了ts12颖壳张开的表型。基于图谱的克隆和转基因互补研究表明，TS12编码抗坏血酸过氧化物酶OsAPX5，ts12中的单核苷酸多态性（SNP）导致OsAPX5蛋白截短。此外，发现OsAPX5在根、茎、叶鞘和幼穗中广泛表达，其蛋白定位于线粒体。在高温条件下，与野生型（WT）相比，ts12突变体积累了更高浓度的活性氧（ROS）。通过酵母双杂交、荧光素酶和下拉试验，我们证明OsAPX5与水稻颖壳发育调节因子OsMADS1相互作用。此外，与颖壳发育相关的OsMADS1、OsMADS5和OsMADS34的表达水平在ts12中与WT相比显著降低。而且，OsAPX5-OsMADS1相互作用促进了OsMADS1和OsMADS34的转录活性。这些结果表明，OsAPX5主要影响ROS水平以及OsMADS1、OsMADS5和OsMADS34的表达，从而调节水稻的高温胁迫反应。
