Cyclin-Dependent Kinase Inhibitors KRP1 and KRP2 Are Involved in Grain Filling and Seed Germination in Rice (Oryza sativa L.)
Cyclin-Dependent Kinase Inhibitors KRP1 and KRP2 Are Involved in Grain Filling and Seed Germination in Rice (Oryza sativa L.)
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细胞周期蛋白依赖性激酶抑制剂 KRP1 和 KRP2 参与水稻 (Oryza sativa L.) 的籽粒灌浆和种子萌发
DOI：
10.3390/ijms21010245
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发表时间：
2020-01-01
影响因子：
5.6
通讯作者：
Wang, Yifeng
中科院分区：
文献类型：
--
作者：
Ajadi, Abolore Adijat;Tong, Xiaohong;Wang, Yifeng
细胞周期蛋白依赖性激酶抑制剂KRP（kip相关蛋白）控制植物细胞周期的进程并调节各种植物发育过程。然而，KRPs在水稻中的功能在很大程度上仍然未知。在这项研究中，两个水稻KRP成员，KRP 1和KRP 2，被发现主要在发育中的种子中表达，并显着诱导外源脱落酸（阿坝）和维生素B6（BR）的应用。亚细胞定位实验表明，KRP 1主要定位在水稻原生质体的细胞核中。KRP 1过表达转基因系（OxKRP 1）、krp 2单突变体（crkrp 2）和krp 1/krp 2双突变体（crkrp 1/krp 2）均表现出显著较小的种子宽度、种子长度和降低的粒重，具有受损的种子萌发和延迟的早期幼苗生长，这表明，干扰KRP 1或KRP 2的正常稳态部分地通过抑制细胞增殖和增大而阻断种子发育，籽粒灌浆和种子萌发。此外，在酵母双杂交系统中，两种细胞周期蛋白依赖性蛋白激酶CDKC;2和CDKF;3可以与KRP 1相互作用，表明KRP 1可能通过这两个靶点调控细胞有丝分裂周期和核内复制。总之，本研究为KRPs在水稻种子成熟和萌发中的调控作用提供了新的视角。
Cyclin-dependent kinase inhibitors known as KRPs (kip-related proteins) control the progression of plant cell cycles and modulate various plant developmental processes. However, the function of KRPs in rice remains largely unknown. In this study, two rice KRPs members, KRP1 and KRP2, were found to be predominantly expressed in developing seeds and were significantly induced by exogenous abscisic acid (ABA) and Brassinosteroid (BR) applications. Sub-cellular localization experiments showed that KRP1 was mainly localized in the nucleus of rice protoplasts. KRP1 overexpression transgenic lines (OxKRP1), krp2 single mutant (crkrp2), and krp1/krp2 double mutant (crkrp1/krp2) all exhibited significantly smaller seed width, seed length, and reduced grain weight, with impaired seed germination and retarded early seedling growth, suggesting that disturbing the normal steady state of KRP1 or KRP2 blocks seed development partly through inhibiting cell proliferation and enlargement during grain filling and seed germination. Furthermore, two cyclin-dependent protein kinases, CDKC;2 and CDKF;3, could interact with KRP1 in a yeast-two-hybrid system, indicating that KRP1 might regulate the mitosis cell cycle and endoreduplication through the two targets. In a word, this study shed novel insights into the regulatory roles of KRPs in rice seed maturation and germination.