Rice Research Institute, Sichuan Agricultural University, Chengdu 611130, China.
Key Laboratory of Southwest Crop Genetic Resources and Genetic Improvement, Ministry of Education, Chengdu 611130, China.
Int J Mol Sci. 2020 Mar 23;21(6):2199. doi: 10.3390/ijms21062199.
Vacuolar invertase is involved in sugar metabolism and plays a crucial role in plant growth and development, thus regulating seed size. However, information linking vacuolar invertase and seed size in rice is limited. Here we characterized a small grain mutant (grain size on chromosome 2) that showed a reduced in grain size and 1000-grain weight compared to the wild type. Map-based cloning and genetic complementation showed that is responsible for the observed phenotype. Loss-of-function of resulted in grains of smaller size when compared to the wild type, while overexpression showed increased grain size. We also obtained a T-DNA insertion mutant of , which is a homolog of and generated double knockout () mutants of and using CRISPR/Cas9. Genetic data showed that , that has no effect on grain size by itself, reduces grain length and width in the absence of . Altered sugar content with increased sucrose and decreased hexose levels, as well as changes vacuolar invertase activities and starch constitution in , , mutants indicate that and affect sucrose metabolism in sink organs. In summary, we identified as a positive regulator of grain size in rice, and while has no function on grain size by itself. In the absence of , it is possible to detect a role of in the regulation of grain size. Both and are involved in sucrose metabolism, and thus regulate grain size. Our findings increase our understanding of the role of and its homolog, , in grain size development and also suggest a potential strategy to improve grain yield in rice.
液泡转化酶参与糖代谢，在植物生长发育中起着关键作用，从而调节种子大小。然而，关于液泡转化酶与水稻种子大小的信息有限。在这里，我们对一个小粒突变体 （位于 2 号染色体上）进行了特征描述，与野生型相比，该突变体的粒长和千粒重均减小。基于图谱的克隆和遗传互补表明， 是导致观察到的表型的原因。与野生型相比， 功能丧失导致粒长减小，而过表达则导致粒长增加。我们还获得了一个 T-DNA 插入突变体 ，它是 的同源物，并利用 CRISPR/Cas9 生成了 和 的双敲除（）突变体。遗传数据表明， 本身对粒长没有影响，但在 缺失的情况下，会降低粒长和粒宽。 、 、 突变体中蔗糖含量增加、己糖含量降低以及液泡转化酶活性和淀粉组成的改变表明 和 影响了库器官中的蔗糖代谢。综上所述，我们确定 是水稻粒长的正调控因子，而 本身对粒长没有功能。在 缺失的情况下，有可能检测到 在调节粒长方面的作用。 和 都参与蔗糖代谢，因此调节粒长。我们的研究结果增加了我们对 及其同源物 在粒长发育中的作用的理解，并为提高水稻的产量提供了一种潜在的策略。
