Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA.
Department of Biological Sciences, Dartmouth College, Hanover, NH 03755.
Development. 2020 Oct 27;147(20):dev191734. doi: 10.1242/dev.191734.
The phytohormone cytokinin regulates diverse aspects of plant growth and development. Our understanding of the metabolism and perception of cytokinin has made great strides in recent years, mostly from studies of the model dicot Here, we employed a CRISPR/Cas9-based approach to disrupt a subset of cytokinin histidine kinase (HK) receptors in rice () in order to explore the role of cytokinin in a monocot species. In and single mutants, the root growth, leaf width, inflorescence architecture and/or floral development were affected. The double mutant showed more substantial defects, including severely reduced root and shoot growth, a smaller shoot apical meristem, and an enlarged root cap. Flowering was delayed in the mutant and the panicle was significantly reduced in size and infertile due to multiple defects in floral development. The mutant also exhibited a severely reduced cytokinin response, consistent with the developmental phenotypes arising from a defect in cytokinin signaling. These results indicate that HK5 and HK6 act as cytokinin receptors, with overlapping functions to regulate diverse aspects of rice growth and development.
植物激素细胞分裂素调节植物生长和发育的各个方面。近年来，我们对细胞分裂素的代谢和感知的理解取得了很大的进展，这主要得益于对双子叶模式植物的研究。在这里，我们采用 CRISPR/Cas9 技术在水稻中破坏一组细胞分裂素组氨酸激酶 (HK) 受体，以探索细胞分裂素在单子叶植物物种中的作用。在 和 单突变体中，根生长、叶片宽度、花序结构和/或花发育受到影响。双 突变体表现出更严重的缺陷，包括根和茎的生长严重减少、茎尖分生组织变小以及根冠增大。 突变体开花延迟，由于花发育的多种缺陷，穗变小且不育。 突变体也表现出严重降低的细胞分裂素反应，与细胞分裂素信号转导缺陷引起的发育表型一致。这些结果表明，HK5 和 HK6 作为细胞分裂素受体发挥作用，具有调节水稻生长和发育各个方面的重叠功能。
