A link between ethylene and auxin uncovered by the characterization of two root-specific ethylene-insensitive mutants in Arabidopsis
A link between ethylene and auxin uncovered by the characterization of two root-specific ethylene-insensitive mutants in Arabidopsis
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DOI：
10.1105/tpc.105.033365
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发表时间：
2005-08-01
期刊：
影响因子：
11.6
通讯作者：
Alonso, JM
中科院分区：
文献类型：
--
作者：
Stepanova, AN;Hoyt, JM;Alonso, JM
植物激素乙烯参与多种发育过程的调节，并作为植物对生物和非生物胁迫因素反应的关键介质。乙烯功能的多样性至少部分地通过与其他激素信号的组合相互作用来实现。在这里，我们表明乙烯触发的根生长抑制，乙烯在拟南芥幼苗中的经典效应之一，是由弱乙烯不敏感2/邻氨基苯甲酸合酶α 1（WEI 2/ASA 1）和WEI 7/邻氨基苯甲酸合酶β 1（ASB 1）基因的作用介导的，这两个基因编码色氨酸生物合成的限速酶邻氨基苯甲酸合酶的α和β亚基.乙烯对WEI 2/ASA 1和WEI 7/ASB 1基因表达的上调导致生长素在初生根尖的积累，而这些基因的功能缺失突变阻止了乙烯介导的生长素的增加.此外，wei 2和wei 7抑制了生长素高产突变体sur 1和sur 2的高生长素表型，表明wei 2和wei 7在生长素生物合成调控中的作用不限于乙烯反应。总之，这些研究结果表明，ASA 1和ASB 1的生长素生产的调控和一个意想不到的节点之间的相互作用乙烯反应和生长素的生物合成在拟南芥中的关键元件。本研究为wei 2和wei 7的根特异乙烯不敏感性提供了机理解释，说明了激素之间的相互作用如何被用于实现反应特异性。
The plant hormone ethylene participates in the regulation of a variety of developmental processes and serves as a key mediator of plant responses to biotic and abiotic stress factors. The diversity of ethylene functions is achieved, at least in part, by combinatorial interactions with other hormonal signals. Here, we show that ethylene- triggered inhibition of root growth, one of the classical effects of ethylene in Arabidopsis thaliana seedlings, is mediated by the action of the WEAK ETHYLENE INSENSITIVE2/ ANTHRANILATE SYNTHASE alpha 1 ( WEI2/ ASA1) and WEI7/ ANTHRANILATE SYNTHASE beta 1 ( ASB1) genes that encode alpha- and beta- subunits of a rate- limiting enzyme of Trp biosynthesis, anthranilate synthase. Upregulation of WEI2/ ASA1 and WEI7/ ASB1 by ethylene results in the accumulation of auxin in the tip of primary root, whereas loss- of- function mutations in these genes prevent the ethylene- mediated auxin increase. Furthermore, wei2 and wei7 suppress the high- auxin phenotypes of superroot1 ( sur1) and sur2, two auxin- overproducing mutants, suggesting that the roles of WEI2 and WEI7 in the regulation of auxin biosynthesis are not restricted to the ethylene response. Together, these findings reveal that ASA1 and ASB1 are key elements in the regulation of auxin production and an unexpected node of interaction between ethylene responses and auxin biosynthesis in Arabidopsis. This study provides a mechanistic explanation for the root- specific ethylene insensitivity of wei2 and wei7, illustrating how interactions between hormones can be used to achieve response specificity.