八月

02

這是郝事之秋陪你的第432天！

Hope everybody can study well and make progress every day!

OST1 Activation by the Brassinosteroid-Regulated Kinase CDG1-Like 1 in Stomatal Closure

First author:Tae-Woo Kim;Affiliations: Hanyang University(漢陽大學):Seoul, Republic of Korea

Corresponding author:Tae-Wuk Kim

Crosstalk between signaling pathways is an important feature of complex regulatory networks. How signal crosstalk circuits are tailored (調整使適應) to suit different needs of various cell types remains a mystery in biology. Brassinosteroid (BR; 油菜素內酯) and abscisic acid (ABA) antagonistically (對抗性地) regulate many aspects of plant growth and development through direct interactions between components of the two signaling pathways. Here we show that BR and ABA synergistically (協同地) regulate stomatal closure through crosstalk between the BR-activated kinase CDG1-LIKE 1 (CDL1) and the OPEN STOMATA 1 (OST1) of the ABA signaling pathway inArabidopsis thaliana. We demonstrate that thecdl1mutant displayed reduced sensitivity to ABA in a stomatal closure assay, similar to theost1mutant. CDL1 and the BR receptor BR-INSENSITIVE 1 (BRI1), but not other downstream components of the BR signaling pathway, were required for BR regulation of stomatal movement. Genetic and biochemical experiments demonstrated that CDL1 activates OST1 by phosphorylating (磷酸化) it on residue Ser7. BR increased phosphorylation of OST1, and the BR-induced OST1 activation was abolished incdl1mutants. Moreover, we found that ABA activates CDL1 in an OST1-dependent manner. Taken together, our findings illustrate a cell-type specific BR signaling branch through which BR acts synergistically with ABA in regulating stomatal closure.

信號通路之間的交聯是複雜調控網路中的一個重要特性。 信號之間的交聯如何調整以適應不同細胞類型的複雜需求仍然是一個謎團。油菜素內脂BR與脫落酸ABA通過兩個信號通路內的組分直接互作拮抗調控植物生長和發育的多個方面。本文的研究顯示擬南芥中BR和ABA通過BR激活激酶CDL1與ABA信號通路中的OST1相互作用協同調控氣孔關閉。cdl1突變體在氣孔關閉試驗中對於ABA的敏感度下降，與ost1突變體的表型類似。CDL1和BR受體BRI1，而非其餘BR信號通路的下游組分，對於BR調控氣孔運動是必需的。遺傳和生化試驗顯示CDL1通過磷酸化OST1上的Ser7殘基來激活OST1。BR增強了OST1的磷酸化程度，並且在cdl1突變體中BR誘導的OST1激活被阻礙。此外，作者還發現ABA以OST1依賴型的形式激活CDL1。綜上，本文的研究闡釋了一種細胞類型特異性BR信號分枝，BR通過與ABA協同互作，共同調控植物的氣孔關閉。

doi: https://doi.org/10.1105/tpc.18.00239

Journal:Plant Cell

First Published: 31 July, 2018

喜歡這篇文章嗎？立刻分享出去讓更多人知道吧！