Convergence of Light and ABA signaling on the ABI5 promoter.
Convergence of Light and ABA signaling on the ABI5 promoter.
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DOI：
10.1371/journal.pgen.1004197
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发表时间：
2014-02
期刊：
影响因子：
4.5
通讯作者：
Holm M
中科院分区：
文献类型：
--
作者：
Xu D;Li J;Gangappa SN;Hettiarachchi C;Lin F;Andersson MX;Jiang Y;Deng XW;Holm M
光是调节植物生长发育的最重要的环境信号之一，脱落酸（阿坝）是一种植物激素，在植物生命周期的许多阶段和植物对各种环境胁迫的响应中起着重要作用。植物如何整合外部光信号和内源阿坝途径以更好地适应和存活仍然知之甚少。在这里，我们表明，BBX 21（也作为盐耐盐同源蛋白2），一个B盒（BBX）蛋白，以前被证明是积极调节幼苗光形态建成，也参与阿坝信号。我们的遗传数据表明，BBX 21可能在阿坝控制种子萌发的过程中作用于几个阿坝不敏感（ABI）基因和伸长下胚轴5（HY 5）的上游。先前的研究表明，HY 5作为ABI 5表达的直接激活剂，并且BBX 21与HY 5相互作用。我们进一步证明BBX 21通过干扰HY 5与ABI 5启动子的结合来负调控ABI 5表达。此外，ABI 5被证明直接激活其自身的表达，而BBX 21通过直接与ABI 5相互作用来负调节这种活性。总之，我们的研究表明BBX 21与HY 5和ABI 5在ABI 5启动子上协调，并且这些转录调节因子协同工作以整合拟南芥中的光和阿坝信号。光照、植物激素脱落酸（阿坝）等多种因素，在植物的整个生命周期中调节多个发育过程。光照促进种子萌发，阿坝维持种子休眠。然而，人们对光和阿坝信号通路如何相互作用知之甚少。据报道，拟南芥HY 5，一个众所周知的bZIP转录因子参与促进幼苗光形态建成，参与阿坝信号通过直接激活ABI 5的表达。在这里，我们报告说，B-box蛋白BBX 21负调控ABI 5的表达干扰HY 5结合到ABI 5启动子。有趣的是，ABI 5被证明直接结合到其自身的启动子并激活其表达，而BBX 21也通过与ABI 5相互作用来负调控这种活性。总之，我们的研究表明，光和阿坝信号通路会聚在ABI 5启动子上，BBX 21在ABI 5启动子上充当ABI 5表达的负调节剂。
Light is one of the most important environmental cues regulating multiple aspects of plant growth and development, and abscisic acid (ABA) is a plant hormone that plays important roles during many phases of the plant life cycle and in plants' responses to various environmental stresses. How plants integrate the external light signal with endogenous ABA pathway for better adaptation and survival remains poorly understood. Here, we show that BBX21 (also known as SALT TOLERANCE HOMOLOG 2), a B-box (BBX) protein previously shown to positively regulate seedling photomorphogenesis, is also involved in ABA signaling. Our genetic data show that BBX21 may act upstream of several ABA INSENSITIVE (ABI) genes and ELONGATED HYPOCOTYL 5 (HY5) in ABA control of seed germination. Previous studies showed that HY5 acts as a direct activator of ABI5 expression, and that BBX21 interacts with HY5. We further demonstrate that BBX21 negatively regulates ABI5 expression by interfering with HY5 binding to the ABI5 promoter. In addition, ABI5 was shown to directly activate its own expression, whereas BBX21 negatively regulates this activity by directly interacting with ABI5. Together, our study indicates that BBX21 coordinates with HY5 and ABI5 on the ABI5 promoter and that these transcriptional regulators work in concert to integrate light and ABA signaling in Arabidopsis thaliana. Many factors such as light, phytohormone abscisic acid (ABA), etc., regulate multiple developmental processes throughout the plants' life cycle. Light promotes seed germination and ABA maintains seed dormancy. However, little is known about how light and ABA signaling pathways interact with each other. It was previously reported that Arabidopsis HY5, a well-known bZIP transcription factor involved in promoting seedling photomorphogenesis, is involved in ABA signaling by directly activating ABI5 expression. Here, we report that the B-box protein BBX21 negatively regulates ABI5 expression by interfering with HY5 binding to the ABI5 promoter. Interestingly, ABI5 was shown to directly bind to its own promoter and activate its expression, whereas BBX21 also negatively regulates this activity by interacting with ABI5. Together, our study shows that light and ABA signaling pathways converge on the ABI5 promoter, on which BBX21 acts as a negative regulator of ABI5 expression.
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DOI：
10.1073/pnas.081594298
发表时间：
2001-04-10
影响因子：
11.1
作者：
Lopez-Molina, L;Mongrand, S;Chua, NH
通讯作者：
Chua, NH
影响因子：
11.6
作者：
Datta, Sourav;Johansson, Henrik;Holm, Magnus
通讯作者：
Holm, Magnus
影响因子：
10.5
作者：
Holm, M;Ma, LG;Deng, XW
通讯作者：
Deng, XW
影响因子：
5.4
作者：
KOORNNEEF, M;JORNA, ML;KARSSEN, CM
通讯作者：
KARSSEN, CM
影响因子：
7.2
作者：
Chang, Chiung-Swey Joanne;Li, Yi-Hang;Wu, Shu-Hsing
通讯作者：
Wu, Shu-Hsing