Zhang Xinwei, Wang Ying, Liu Mingyu, Yan Peiwen, Niu Fuan, Ma Fuying, Hu Jian, He Shicong, Cui Jinhao, Yuan Xinyu, Yang Jinshui, Cao Liming, Luo Xiaojin
State Key Laboratory of Genetic Engineering and Engineering Research Center of Gene Technology (Ministry of Education), School of Life Sciences, Fudan University, Shanghai, China.
Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Department of Ecology and Evolutionary Biology, School of Life Sciences, Fudan University, Shanghai, China.
Rice (N Y). 2024 May 23;17(1):36. doi: 10.1186/s12284-024-00715-x.
Yield and quality are the two most important traits in crop breeding. Exploring the regulatory mechanisms that affect both yield and quality traits is of great significance for understanding the molecular genetic networks controlling these key crop attributes. Expansins are cell wall loosening proteins that play important roles in regulating rice grain size.
We investigated the effect of OsEXPA7, encoding an expansin, on rice grain size and quality. OsEXPA7 overexpression resulted in increased plant height, panicle length, grain length, and thousand-grain weight in rice. OsEXPA7 overexpression also affected gel consistency and amylose content in rice grains, thus affecting rice quality. Subcellular localization and tissue expression analyses showed that OsEXPA7 is localized on the cell wall and is highly expressed in the panicle. Hormone treatment experiments revealed that OsEXPA7 expression mainly responds to methyl jasmonate, brassinolide, and gibberellin. Transcriptome analysis and RT-qPCR experiments showed that overexpression of OsEXPA7 affects the expression of OsJAZs in the jasmonic acid pathway and BZR1 and GE in the brassinosteroid pathway. In addition, OsEXPA7 regulates the expression of key quantitative trait loci related to yield traits, as well as regulates the expression levels of BIP1 and bZIP50 involved in the seed storage protein biosynthesis pathway.
These results reveal that OsEXPA7 positively regulates rice yield traits and negatively regulates grain quality traits by involving plant hormone pathways and other trait-related pathway genes. These findings increase our understanding of the potential mechanism of expansins in regulating rice yield and quality traits and will be useful for breeding high-yielding and high-quality rice cultivars.
产量和品质是作物育种中两个最重要的性状。探索影响产量和品质性状的调控机制对于理解控制这些关键作物属性的分子遗传网络具有重要意义。扩张蛋白是细胞壁松弛蛋白，在调节水稻粒型方面发挥重要作用。
我们研究了编码扩张蛋白的OsEXPA7对水稻粒型和品质的影响。OsEXPA7过表达导致水稻株高、穗长、粒长和千粒重增加。OsEXPA7过表达还影响水稻籽粒的胶稠度和直链淀粉含量，从而影响水稻品质。亚细胞定位和组织表达分析表明，OsEXPA7定位于细胞壁，在穗中高表达。激素处理实验表明，OsEXPA7的表达主要响应茉莉酸甲酯、油菜素内酯和赤霉素。转录组分析和RT-qPCR实验表明，OsEXPA7过表达影响茉莉酸途径中OsJAZs以及油菜素类固醇途径中BZR1和GE的表达。此外，OsEXPA7调节与产量性状相关的关键数量性状位点的表达，以及调节参与种子贮藏蛋白生物合成途径的BIP1和bZIP50的表达水平。
这些结果表明，OsEXPA7通过参与植物激素途径和其他性状相关途径基因，正向调节水稻产量性状，负向调节籽粒品质性状。这些发现增进了我们对扩张蛋白调控水稻产量和品质性状潜在机制的理解，将有助于培育高产优质水稻品种。
