Faculty of Life and Environmental Sciences, University of Tsukuba, Ibaraki, Tsukuba, 305-8572, Japan.
J Plant Res. 2020 Nov;133(6):883-895. doi: 10.1007/s10265-020-01223-x. Epub 2020 Sep 14.
The tapetum plays important roles in anther development by providing materials for pollen-wall formation and nutrients for pollen development. Here, we report the characterization of a male-sterile mutant of glycine-rich protein 2 (OsGRP2), which exhibits irregular cell division and dysfunction of the tapetum. GRP is a cellwall structural protein present in the cell walls of diverse plant species, but its function is unclear in pollen development. We found that few GRP genes are expressed in rice and thus focused on one highly expressed gene, OsGRP2. The tapetal cell walls of an OsGRP2 mutant did not thicken at the pollen mothercell stage, as a result, pollen maturation and fertility rate decreased. High OsGRP2 expression was detected in male-floral organs, and OsGRP2 was distributed in the tapetum. OsGRP2 participated in establishment of the cellwall network during early tapetum development. In conclusion, our results indicate that OsGRP2 plays important roles in the differentiation and function of the tapetum.
绒毡层通过为花粉壁形成提供物质和为花粉发育提供营养，在花药发育中起着重要作用。在这里，我们报道了一个富含甘氨酸蛋白 2（OsGRP2）的雄性不育突变体的特征，该突变体表现出不规则的细胞分裂和绒毡层功能障碍。GRP 是一种存在于多种植物细胞壁中的细胞壁结构蛋白，但它在花粉发育中的功能尚不清楚。我们发现水稻中表达的 GRP 基因很少，因此我们专注于一个高度表达的基因 OsGRP2。在 OsGRP2 突变体中，绒毡层细胞壁在花粉母细胞阶段没有增厚，因此花粉成熟和结实率降低。在雄性花器官中检测到高表达的 OsGRP2，并且 OsGRP2 分布在绒毡层中。OsGRP2 参与了早期绒毡层发育过程中细胞壁网络的建立。总之，我们的结果表明 OsGRP2 在绒毡层的分化和功能中起着重要作用。
