Mutant analysis in Arabidopsis provides insight into the molecular mode of action of the auxinic herbicide dicamba.
Mutant analysis in Arabidopsis provides insight into the molecular mode of action of the auxinic herbicide dicamba.
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DOI：
10.1371/journal.pone.0017245
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发表时间：
2011-03-08
期刊：
影响因子：
3.7
通讯作者：
Singh KB
中科院分区：
文献类型：
--
作者：
Gleason C;Foley RC;Singh KB
模拟天然生长素吲哚-3-乙酸的除草剂被广泛用于杂草防治。麦草畏是一种常见的类生长素除草剂，但尽管它被广泛使用，但植物基因对麦草畏的反应从未被广泛研究过。为了进一步了解麦草畏的作用模式，我们利用拟南芥生长素不敏感突变体，比较它们对麦草畏和广泛研究的抗氧化除草剂2,4-二氯苯氧乙酸（2,4- d）的敏感性。突变体axr4-2破坏了生长素向细胞的运输，对2,4- d具有抗性，但对麦草畏敏感。通过比较生长素信号F-box受体突变体（tir1-1, afb1, afb2， afb3和afb5）对麦草畏的抗性，只有tir1-1和afb5对麦草畏具有抗性，并且这种抗性在tir1-1/afb5双突变体中是加性的。有趣的是，tir1-1对2,4- d有抗性，而afb5没有。麦草畏诱导基因表达的全基因组分析显示，施药10小时后，麦草畏刺激了许多应激响应和信号传导基因，包括生长素、乙烯和脱落酸（ABA）的生物合成或信号传导基因，其中TIR1和AFB5是某些基因对麦草畏响应所必需的。对麦草畏调控的基因表达和生长素受体选择性的研究，为麦草畏调控的信号传导提供了分子视角，并有助于作物植物新型抗除草剂的开发。
Herbicides that mimic the natural auxin indole-3-acetic acid are widely used in weed control. One common auxin-like herbicide is dicamba, but despite its wide use, plant gene responses to dicamba have never been extensively studied. To further understand dicamba's mode of action, we utilized Arabidopsis auxin-insensitive mutants and compared their sensitivity to dicamba and the widely-studied auxinic herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). The mutant axr4-2, which has disrupted auxin transport into cells, was resistant to 2,4-D but susceptible to dicamba. By comparing dicamba resistance in auxin signalling F-box receptor mutants (tir1-1, afb1, afb2, afb3, and afb5), only tir1-1 and afb5 were resistant to dicamba, and this resistance was additive in the double tir1-1/afb5 mutant. Interestingly, tir1-1 but not afb5 was resistant to 2,4-D. Whole genome analysis of dicamba-induced gene expression showed that 10 hours after application, dicamba stimulated many stress-responsive and signalling genes, including those involved in biosynthesis or signalling of auxin, ethylene, and abscisic acid (ABA), with TIR1 and AFB5 required for the dicamba-responsiveness of some genes. Research into dicamba-regulated gene expression and the selectivity of auxin receptors has provided molecular insight into dicamba-regulated signalling and could help in the development of novel herbicide resistance in crop plants.