The AP2/ERF Transcription Factor TINY Modulates Brassinosteroid-Regulated Plant Growth and Drought Responses in Arabidopsis
The AP2/ERF Transcription Factor TINY Modulates Brassinosteroid-Regulated Plant Growth and Drought Responses in Arabidopsis
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DOI：
10.1105/tpc.18.00918
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发表时间：
2019-08-01
期刊：
影响因子：
11.6
通讯作者：
Yin, Yanhai
中科院分区：
文献类型：
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作者：
Xie, Zhouli;Nolan, Trevor;Yin, Yanhai
aptala2 /乙烯响应因子（AP2/ERF）家族转录因子在胁迫应答中具有良好的功能，但其在油菜素内酯（BR）调控的生长和胁迫应答中的作用尚未确定。在这里，我们发现拟南芥（Arabidopsis thaliana）胁迫诱导的AP2/ERF转录因子TINY抑制br调控的生长，同时促进干旱响应。过表达tiny的植物生长发育迟缓，对BR生物合成抑制剂的敏感性增加，BR应答基因表达受损。相比之下，微小的tiny2 tiny3三突变体增加了br调控的生长和br响应基因的表达。TINY通过激活干旱响应基因和促进脱落酸介导的气孔关闭来积极调节干旱反应。全球基因表达研究表明，TINY和BRs对植物生长和胁迫应答基因的影响相反。TINY在这些基因的调控中与油菜素类固醇insensitive1 -乙基甲烷磺酸盐抑制sor1 （BES1）相互作用并拮抗。糖原合成酶激酶3样蛋白激酶BR- insensitive2 （BIN2）是BR通路的负调控因子，可磷酸化并稳定TINY，为BR介导的TINY下调提供了一种在最佳生长条件下防止应激反应激活的机制。综上所述，我们的研究结果表明，BR信号通过BIN2磷酸化负调控TINY，而TINY正调控干旱反应，并通过TINY- bes1拮抗相互作用抑制BR介导的生长。因此，我们的研究结果为br调控的生长和干旱响应的协调提供了见解。
APETALA2/ETHYLENE RESPONSIVE FACTOR (AP2/ERF) family transcription factors have well-documented functions in stress responses, but their roles in brassinosteroid (BR)-regulated growth and stress responses have not been established. Here, we show that the Arabidopsis (Arabidopsis thaliana) stress-inducible AP2/ERF transcription factor TINY inhibits BR-regulated growth while promoting drought responses. TINY-overexpressing plants have stunted growth, increased sensitivity to BR biosynthesis inhibitors, and compromised BR-responsive gene expression. By contrast, tiny tiny2 tiny3 triple mutants have increased BR-regulated growth and BR-responsive gene expression. TINY positively regulates drought responses by activating drought-responsive genes and promoting abscisic acid-mediated stomatal closure. Global gene expression studies revealed that TINY and BRs have opposite effects on plant growth and stress response genes. TINY interacts with and antagonizes BRASSINOSTERIOID INSENSITIVE1-ETHYL METHANESULFONATE SUPRESSOR1 (BES1) in the regulation of these genes. Glycogen synthase kinase 3-like protein kinase BR-INSENSITIVE2 (BIN2), a negative regulator in the BR pathway, phosphorylates and stabilizes TINY, providing a mechanism for BR-mediated downregulation of TINY to prevent activation of stress responses under optimal growth conditions. Taken together, our results demonstrate that BR signaling negatively regulates TINY through BIN2 phosphorylation and TINY positively regulates drought responses, as well as inhibiting BR-mediated growth through TINY-BES1 antagonistic interactions. Our results thus provide insight into the coordination of BR-regulated growth and drought responses.