Tiller Bud Formation Regulators MOC1 and MOC3 Cooperatively Promote Tiller Bud Outgrowth by Activating FON1 Expression in Rice
Tiller Bud Formation Regulators MOC1 and MOC3 Cooperatively Promote Tiller Bud Outgrowth by Activating FON1 Expression in Rice
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DOI：
10.1016/j.molp.2019.04.008
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发表时间：
2019-08-05
期刊：
影响因子：
27.5
通讯作者：
Yu, Hong
中科院分区：
文献类型：
--
作者：
Shao, Gaoneng;Lu, Zefu;Yu, Hong
分蘖是水稻最重要的农艺性状之一。水稻分蘖的发育可分为两个主要过程：腋芽的形成和腋芽的伸长。通过遗传学研究已经鉴定了几个水稻芽形成的关键基因，然而，它们的分子功能和相互关系在很大程度上仍然是未知的。在这里，我们报告了MOC 1和MOC 3/TILLERS ABSENT 1/STERILE AND REDUCED TILLLERS 1（MOC 3/TAB 1/SRT 1），这两个水稻分蘖形成的重要调节因子，通过物理相互作用上调CLAVATA 1同源基因FLORAL ORGAN NUMBER 1（FON 1）的表达来调节分蘖芽的生长。我们发现MOC 3能够直接结合FON 1的启动子并随后激活FON 1的表达。MOC 1作为MOC 3的共激活因子发挥作用，而它不能直接结合FON 1启动子，并在MOC 3存在下进一步激活FON 1表达。因此，FON 1在腋生分生组织高度表达，并在moc 1和moc 3突变体中显示出显著降低的表达水平。FON 1的功能丧失突变体表现出正常的芽形成，但有缺陷的芽生长和分蘖数减少。这些结果揭示了MOC 1和MOC 3的联合转录调控机制，为控制分蘖芽的形成和生长建立了新的框架。
Tillering in rice is one of the most important agronomic traits. Rice tiller development can be divided into two main processes: the formation of the axillary bud and its subsequent outgrowth. Several genes critical for bud formation in rice have been identified by genetic studies; however, their molecular functions and relationships are still largely unknown. Here, we report that MONOCULM 1 (MOC1) and MONOCULM 3/TILLERS ABSENT 1/STERILE AND REDUCED TILLERING 1 (MOC3/TAB1/SRT1), two vital regulators for tiller formation in rice, physically interact to regulate tiller bud outgrowth through upregulating the expression of FLORAL ORGAN NUMBER1 (FON1), the homolog of CLAVATA1 in rice. We found that MOC3 is able to directly bind the promoter of FON1 and subsequently activate FON1 expression. MOC1 functions as a coactivator of MOC3, whereas it could not directly bind the FON1 promoter, and further activated FON1 expression in the presence of MOC3. Accordingly, FON1 is highly expressed at axillary meristems and shows remarkably decreased expression levels in moc1 and moc3 mutants. Loss-of-function mutants of FON1 exhibit normal bud formation but defective bud outgrowth and reduced tiller number. Collectively, these results shed light on a joint transcriptional regulatory mechanim by MOC1 and MOC3, and establish a new framework for the control of tiller bud formation and outgrowth.