Arabidopsis Aux/IAA genes are involved in brassinosteroid-mediated growth responses in a manner dependent on organ type
Arabidopsis Aux/IAA genes are involved in brassinosteroid-mediated growth responses in a manner dependent on organ type
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DOI：
10.1111/j.1365-313x.2005.02582.x
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发表时间：
2006-01-01
期刊：
影响因子：
7.2
通讯作者：
Fujioka, S
中科院分区：
文献类型：
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作者：
Nakamura, A;Nakajima, N;Fujioka, S
我们研究了生长素/吲哚-3-乙酸（Aux/IAA）蛋白是否参与油菜素内酯（BR）反应，这是生长素信号转导的关键参与者。iaa7/axr2-1和iaa17/axr3-3突变体表现出异常的BR敏感性和异常的BR诱导基因表达，以器官依赖的方式表达。两种生长素抑制剂在BR反应方面进行了测试。Yokonolide B抑制BR反应，而对氯苯氧异丁酸不抑制BR反应。DNA微阵列分析显示，iaa7中有108个基因上调，只有8个基因下调。在axr2中上调或下调的基因中，22%是油菜素内酯诱导基因，20%是生长素诱导基因，大多数对BR和生长素都不敏感。brassinazole是一种BR生物合成抑制剂，可抑制生长素诱导DR5-GUS基因，该基因由合成生长素反应元件、最小启动子和β -葡萄糖醛酸酶组成。这些结果表明，Aux/IAA蛋白在生长素和BR信号通路中起作用，IAA蛋白作为信号元件以依赖于器官类型的方式调节BR敏感性。
We examined whether auxin/indole-3-acetic acid (Aux/IAA) proteins, which are key players in auxin-signal transduction, are involved in brassinosteroid (BR) responses. iaa7/axr2-1 and iaa17/axr3-3 mutants showed aberrant BR sensitivity and aberrant BR-induced gene expression in an organ-dependent manner. Two auxin inhibitors were tested in terms of BR responses. Yokonolide B inhibited BR responses, whereas p-chlorophenoxyisobutyric acid did not inhibit BR responses. DNA microarray analysis revealed that 108 genes were up-regulated, while only eight genes were down-regulated in iaa7. Among the genes that were up- or down-regulated in axr2, 22% were brassinolide-inducible genes, 20% were auxin-inducible genes, and the majority were sensitive neither to BR nor to auxin. An inhibitor of BR biosynthesis, brassinazole, inhibited auxin induction of the DR5-GUS gene, which consists of a synthetic auxin-response element, a minimum promoter, and a beta-glucuronidase. These results suggest that Aux/IAA proteins function in auxin- and BR-signaling pathways, and that IAA proteins function as the signaling components modulating BR sensitivity in a manner dependent on organ type.