遗传发育所在Plant Cell揭示植物侧生分生组织发生的分子机制
中科院遗传与发育生物学研究所焦雨铃课题组表明侧生分生组织的形成需要两类经典植物激素的协调调控，揭示侧生分生组织发生的分子机制，还发现了一批能够调控侧生分生组织发生的基因。相关文章发表于2014年5月21日的《Plant Cell 》杂志上。
植物的分枝产生于叶腋处形成的侧生分生组织所形成的侧芽。虽然对侧芽的休眠与伸长研究在近年内取得了长足进展，但对侧生分生组织如何产生还了解不多。
焦雨铃课题组的研究表明侧生分生组织的形成需要两类经典植物激素的协调调控。在拟南芥中，侧生分生组织形成的叶腋处首先出现生长素的低点，此后叶腋处出现细胞分裂素的活跃信号。此研究进而在拟南芥和番茄中证明：先后发生的生长素低点和细胞分裂素高点都为侧生分生组织的形成所必需。
此外，生长素低点的产生依赖于PIN蛋白介导的生长素细胞外运。该工作不仅为侧生分生组织的发生提供了机制上的解释，还发现了一批能够调控侧生分生组织发生的基因。此研究获得的结果对于分子育种，特别是作物穗数和穗粒数的调控，有一定借鉴意义。
该研究成果于2014年5月21日在线发表于Plant Cell 杂志(DOI: 10.1105/tpc.114.123083)。Plant Cell 杂志编辑撰文对本研究及相关工作进行介绍(DOI: 10.1105/tpc.114.127860)，高度评价本研究的意义。焦雨铃课题组的汪颖博士为该文章的第一作者。该研究得到了科技部、自然科学基金委和中科院的资助。
原文摘要：
The Stem Cell Niche in Leaf Axils Is Established by Auxin and Cytokinin in Arabidopsis
Ying Wang, Jin Wang, Bihai Shi, Ting Yu, Jiyan Qi, Elliot M. Meyerowitz and Yuling Jiao
Plants differ from most animals in their ability to initiate new cycles of growth and development, which relies on the establishment and activity of branch meristems harboring new stem cell niches. In seed plants, this is achieved by axillary meristems, which are established in the axil of each leaf base and develop into lateral branches. Here, we describe the initial processes of Arabidopsis thaliana axillary meristem initiation. Using reporter gene expression analysis, we find that axillary meristems initiate from leaf axil cells with low auxin through stereotypical stages. Consistent with this, ectopic overproduction of auxin in the leaf axil efficiently inhibits axillary meristem initiation. Furthermore, our results demonstrate that auxin efflux is required for the leaf axil auxin minimum and axillary meristem initiation. After lowering of auxin levels, a subsequent cytokinin signaling pulse is observed prior to axillary meristem initiation. Genetic analysis suggests that cytokinin perception and signaling are both required for axillary meristem initiation. Finally, we show that cytokinin overproduction in the leaf axil partially rescue axillary meristem initiation-deficient mutants. These results define a mechanistic framework for understanding axillary meristem initiation.
作者：遗传发育所
