Five components of the ethylene-response pathway identified in a screen for weak ethylene-insensitive mutants in Arabidopsis
Five components of the ethylene-response pathway identified in a screen for weak ethylene-insensitive mutants in Arabidopsis
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DOI：
10.1073/pnas.0438070100
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发表时间：
2003-03-04
影响因子：
11.1
通讯作者：
Ecker, JR
中科院分区：
文献类型：
--
作者：
Alonso, JM;Stepanova, AN;Ecker, JR
通过低剂量筛选筛选“弱”乙烯不敏感突变体，鉴定出5个乙烯不敏感位点（wei 1-wei 5）。wei 1、wei 2和wei 3幼苗仅在根中表现出激素不敏感性，而wei 4和wei 5幼苗在根和下胚轴中都表现出激素不敏感性。使用定位克隆方法分离对应于wei 1、wei 4和wei 5的基因。wei 1突变体在TIR 1中具有隐性突变，该突变体编码参与生长素反应的SCF蛋白泛素连接酶的组分。wei 4是一个显性突变体，由乙烯受体ER 5突变引起，而wei 5是一个半显性突变体，由EIN 3相关转录因子基因EIL 1突变引起。同时失去功能WEI 5/EIL 1和EIN 3几乎完全取消了乙烯反应黄化苗，和成年植物是非常容易感染的坏死营养型真菌病原体灰葡萄孢。此外，wei 5/eil 1 ein 3双突变体能够完全抑制ctr 1引起的组成型信号，这表明这些基因产物之间的协同作用。与以前已知的根乙烯不敏感突变体，wei 2和wei 3不受影响，在他们的反应生长素和重力表现出正常的反应。遗传作图研究表明，wei 2和wei 3对应于以前未确定的乙烯途径基因，可能控制细胞伸长过程中发挥作用的乙烯和生长素反应途径的交叉点。
Five ethylene-insensitive loci (wei1-wei5) were identified by using a low-dose screen for "weak" ethylene-insensitive mutants. wei1, wei2, and wei3 seedlings showed hormone insensitivity only in roots, whereas wei4 and wei5 displayed insensitivity in both roots and hypocotyls. The genes corresponding to wei1, wei4, and wei5 were isolated using a positional cloning approach. The wei1 mutant harbored a recessive mutation in TIR1, which encodes a component of the SCF protein ubiquitin ligase involved in the auxin response. wei4, a dominant mutant, resulted from a mutation in the ethylene receptor ER5, whereas wei5, a semidominant mutant, was caused by a mutation in the EIN3-related transcription factor gene EIL1. The simultaneous loss of functional WEI5/EIL1 and EIN3 nearly completely abolished the ethylene response in etiolated seedlings, and adult plants were highly susceptible to infection by the necrotrophic fungal pathogen Botrytis cinerea. Moreover, wei5/eil1 ein3 double mutants were able to fully suppress constitutive signaling caused by ctr1, suggesting a synergistic interaction among these gene products. Unlike previously known root ethylene-insensitive mutants, wei2 and wei3 were not affected in their response to auxin and showed a normal response to gravity. Genetic mapping studies indicate that wei2 and wei3 correspond to previously unidentified ethylene pathway genes that may control cell-elongation processes functioning at the intersection of the ethylene and auxin response pathways.