BES1 is activated by EMS1-TPD1-SERK1/2-mediated signaling to control tapetum development in Arabidopsis thaliana

First author: Weiyue Chen; Affiliations: Lanzhou University (兰州大学): Lanzhou, China

Corresponding author: Jia Li 

BES1 and BZR1 were originally identified as two key transcription factors specifically regulating brassinosteroid (BR)-mediated gene expression. They belong to a family consisting of six members, BES1, BZR1, BEH1, BEH2, BEH3, and BEH4. bes1 and bzr1 single mutants do not exhibit any characteristic BR phenotypes, suggesting functional redundancy of these proteins. Here, by generating higher order mutants, we show that a quintuple mutant is male sterile due to defects in tapetum and microsporocyte development in anthers. Our genetic and biochemical analyses demonstrate that BES1 family members also act as downstream transcription factors in the EMS1-TPD1-SERK1/2 pathway. Ectopic expression of both TPD1 and EMS1 in bri1-116, a BR receptor null mutant, leads to the accumulation of non-phosphorylated, active BES1, similar to activation of BES1 by BRI1-BR-BAK1 signaling. These data suggest that two distinctive receptor-like kinase-mediated signaling pathways share BES1 family members as downstream transcription factors to regulate different aspects of plant development.

BES1和BZR1最初被鉴定为特异性调控油菜素内酯介导的基因表达的两个关键转录因子。这两个基因属于一个含有6个成员的基因家族，即BES1、BZR1、BEH1、BEH2、BEH3和BEH4。bes1和bzr1单突变体并不会出现任何与BR相关的表型，说明这些蛋白之间可能存在功能冗余。本文中，作者通过构建高阶突变体发现了一个五突由于花药绒毡层与小孢子母细胞发育的缺陷导致了雄性不育。遗传学和生化试验显示BES1家族的成员同样在EMS1-TPD1-SERK1/2通路的下游发挥功能。在一个BR受体缺陷突变体bri1-116中异位表达TPD1和EMS1基因能够积累非磷酸化并具有活性的BES1，与受BRI1-BR-BAK1信号激活的BES1类似。本文的数据揭示了两个不同的类受体激酶介导的信号转导通路下游都通过转录因子家族BES1的成员调控不同的植物发育进程。

通讯：黎家 (http://lifesc.lzu.edu.cn/content-267-1.html)

个人简介：1984年，兰州大学，学士；1989年，中国科学院植物研究所，硕士；1995年，美国弗吉尼亚理工大学，博士；1997-2002年，美国密苏里大学哥伦比亚分校；博士后。

研究方向：1. 油菜素内酯的信号传递、合成、及代谢途径的分子调控机制；2. 拟南芥类受体蛋白激酶的生物学功能；3. 类受体激酶介导的植物细胞凋亡的分子机理。

doi: https://doi.org/10.1038/s41467-019-12118-4

Journal: Nature Communications

Published online: September 13, 2019