赤黴素(Gibberellins,GAs)調控茉莉酸甲酯(JA)的信號轉導途徑,而JA信號途徑在植物發育和脅迫誘導中起著非常重要的作用。JA作為植物發育中重要的信號途徑,一直是研究熱點。然而,植物各種信號途徑之間的調控網絡複雜,大部分植物激素之間的相互作用仍然不清楚。
DELLAs通過與JAZs的競爭性結合調控JA信號途徑的「抑制釋放模型」圖
中科院華南植物園植物種質創新與基因發掘領域夏快飛博士與新加坡國立大學植物發育學實驗室的侯興亮博士後,一起致力於JA調控途徑中JAZ1(茉莉酸受體ZIM結構域蛋白)、DELLA(DELLA家族蛋白)、MYC2(MYC轉錄因子)及GA(赤黴素)之間的相互作用研究,發現DELLAs在JA信號途徑中起著重要作用,同時也揭示JA信號途徑可能通過DELLAs與別的信號途徑起著重要的聯繫作用。沒有JA,JAZs能穩定的與MYC2結合,因此抑制了MYC2作為轉錄激活子的活性。而加入JA,JA則與JAZs結合,釋放出MYC2,從而激活了JA途徑中的反應基因的表達。在JA信號途徑中沒有GA,DELLAs能穩定的與JAZs結合,釋放出MYC2激活JA途徑。加入GA,則GA促進了DELLAs的降解,導致JAZ-MYC2複合子的形成,從而抑制了JA信號途徑。
該研究結果已發表在國際重要刊物Developmental Cell(DOI 10.1016/j.devcel. 2010.10.024)上。(生物谷Bioon.com)
生物谷推薦原文出處:
Developmental Cell DOI 10.1016/j.devcel. 2010.10.024
DELLAs Modulate Jasmonate Signaling via Competitive Binding to JAZs
Authors
Xingliang Hou, Li Yen Candy Lee, Kuaifei Xia, Yuanyuan Yan, Hao Yu
Highlights
Gibberellins (GAs) inhibit DELLA-mediated upregulation of jasmonate (JA) target genes
DELLAs compete the JA signaling repressor JAZ1 away from the JA effector MYC2
DELLA/JAZ binding derepresses MYC2's ability to regulate JA-responsive genes
DELLAs promote cellular competence to respond to JA
Summary
Gibberellins (GAs) modulate jasmonate (JA) signaling, which is essential for stress response and development in plants. However, the molecular details of such phytohormone interaction remain largely unknown. Here, we show that the JA ZIM-domain 1 (JAZ1) protein, a key repressor of JA signaling, interacts in vivo with DELLA proteins, repressors of the GA pathway. DELLAs prevent inhibitory JAZ1 interaction with a key transcriptional activator of JA responses, MYC2, and, thus, enhance the ability of MYC2 to regulate its target genes. Conversely, GA triggers degradation of DELLAs, which allows JAZ1 to bind MYC2 and suppress MYC2-dependent JA-signaling outputs. Therefore, our results reveal one means by which GAs suppress cellular competence to respond to JA. Because DELLAs serve as central regulators that mediate the crosstalk of various phytohormones, our model also suggests a candidate mechanism by which JA signaling may be fine-tuned by other signaling pathways through DELLAs.