Arabidopsis cryptochrome 1 promotes stomatal development through repression of AGB1 inhibition of SPEECHLESS DNA-binding activity
Arabidopsis cryptochrome 1 promotes stomatal development through repression of AGB1 inhibition of SPEECHLESS DNA-binding activity
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拟南芥隐花色素1通过抑制AGB1抑制SPEECHLESS DNA结合活性促进气孔发育
DOI：
10.1111/jipb.13168
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发表时间：
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影响因子：
11.4
通讯作者：
Yang Hong-Quan
中科院分区：
文献类型：
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作者：
Cao Xiaoli;Xu Pengbo;Liu Yao;Yang Guangqiong;Liu Minqing;Chen Li;Cheng Yingyu;Xu Peng;Miao Langxi;Mao Zhilei;Wang Wenxiu;Kou Shuang;Guo Tongtong;Yang Hong-Quan
隐花色素是蓝光光感受器，介导植物和哺乳动物的各种光反应。已知异源三聚体 G 蛋白可调节植物和哺乳动物的各种生理过程。在拟南芥中，隐花色素 1 (CRY1) 和 G 蛋白 β 亚基 AGB1 发挥拮抗作用来调节气孔发育。 CRY1 和 AGB1 调节这一过程的分子机制仍不清楚。在这里，我们发现拟南芥CRY1部分通过AGB1发挥作用，而AGB1通过SPEECHLESS (SPCH)发挥作用，SPCH是一种驱动气孔起始和增殖的主转录因子，以调节气孔发育。我们证明 AGB1 与 SPCH 发生物理相互作用，阻断 SPCH 的 bHLH DNA 结合域并抑制其 DNA 结合活性。此外，我们证明光激发的 CRY1 抑制 AGB1 与 SPCH 的相互作用，从而释放 AGB1 对 SPCH DNA 结合活性的抑制，导致 SPCH 靶基因的表达，促进气孔发育。综上所述，我们的结果表明，CRY1 促进气孔发育的机制涉及通过 CRY1 抑制 AGB1-SPCH 相互作用介导的 SPCH DNA 结合活性的正向调节。我们提出，CRY1 和 AGB1 对 SPCH DNA 结合活性的拮抗调节可能使植物能够平衡光和 G 蛋白信号传导并优化气孔密度和模式。
Cryptochromes are blue light photoreceptors that mediate various light responses in plants and mammals. The heterotrimeric G‐protein is known to regulate various physiological processes in plants and mammals. InArabidopsis, cryptochrome 1 (CRY1) and the G‐protein β subunit AGB1 act antagonistically to regulate stomatal development. The molecular mechanism by which CRY1 and AGB1 regulate this process remains unknown. Here, we show thatArabidopsisCRY1 acts partially through AGB1, and AGB1 acts through SPEECHLESS (SPCH), a master transcription factor that drives stomatal initiation and proliferation, to regulate stomatal development. We demonstrate that AGB1 physically interacts with SPCH to block the bHLH DNA‐binding domain of SPCH and inhibit its DNA‐binding activity. Moreover, we demonstrate that photoexcited CRY1 represses the interaction of AGB1 with SPCH to release AGB1 inhibition of SPCH DNA‐binding activity, leading to the expression of SPCH‐target genes promoting stomatal development. Taken together, our results suggest that the mechanism by which CRY1 promotes stomatal development involves positive regulation of the DNA‐binding activity of SPCH mediated by CRY1 inhibition of the AGB1‐SPCH interaction. We propose that the antagonistic regulation of SPCH DNA‐binding activity by CRY1 and AGB1 may allow plants to balance light and G‐protein signaling and optimize stomatal density and pattern.