National Institute of Plant Genome Research (NIPGR), New Delhi 110067, India; Interdisciplinary Centre for Plant Genomics and Department of Plant Molecular Biology, University of Delhi, South Campus (UDSC), New Delhi 110021, India.
National Institute of Plant Genome Research (NIPGR), New Delhi 110067, India.
Plant Sci. 2022 Aug;321:111297. doi: 10.1016/j.plantsci.2022.111297. Epub 2022 Apr 30.
Pollen development and its germination are obligatory for the reproductive success of flowering plants. Calcium-dependent protein kinases (CPKs, also known as CDPKs) regulate diverse signaling pathways controlling plant growth and development. Here, we report the functional characterization of a novel OsCPK29 from rice, which is mainly expressed during pollen maturation stages of the anther. OsCPK29 exclusively localizes in the nucleus, and its N-terminal variable domain is responsible for retaining it in the nucleus. OsCPK29 knockdown rice plants exhibit reduced fertility, set fewer seeds, and produce collapsed non-viable pollen grains that do not germinate. Cytological analysis of anther semi-thin sections during different developmental stages suggested that pollen abnormalities appear after the vacuolated pollen stage. Detailed microscopic study of pollen grains further revealed that they were lacking the functional intine layer although exine layer was present. Consistent with that, downregulation of known intine development-related rice genes was also observed in OsCPK29 silenced anthers. Furthermore, it has been demonstrated that OsCPK29 interacts in vitro as well as in vivo with the MADS68 transcription factor which is a known regulator of pollen development. Therefore, phenotypic observations and molecular studies suggest that OsCPK29 is an important regulator of pollen development in rice.
花粉的发育和萌发对于开花植物的生殖成功是必需的。钙依赖蛋白激酶（CPKs，也称为 CDPKs）调节控制植物生长和发育的多种信号通路。在这里，我们报告了一个来自水稻的新型 OsCPK29 的功能特征，它主要在花药的花粉成熟阶段表达。OsCPK29 仅定位于细胞核中，其 N 端可变结构域负责将其保留在核内。OsCPK29 敲低的水稻植株表现出生育力降低、结实率降低、产生崩溃的非活性花粉粒，这些花粉粒不发芽。对不同发育阶段花药半薄切片的细胞学分析表明，花粉异常出现在液泡化花粉阶段之后。对花粉粒的详细显微镜研究进一步表明，尽管有外壁层，但它们缺乏功能内皮层。与此一致，在沉默的 OsCPK29 花药中也观察到已知的内皮层发育相关水稻基因的下调。此外，已经证明 OsCPK29 在体外和体内均与 MADS68 转录因子相互作用，该因子是花粉发育的已知调节剂。因此，表型观察和分子研究表明，OsCPK29 是水稻花粉发育的重要调节剂。
