A small acidic protein 1 (SMAP1) mediates responses of the Arabidopsis root to the synthetic auxin 2,4-dichlorophenoxyacetic acid
A small acidic protein 1 (SMAP1) mediates responses of the Arabidopsis root to the synthetic auxin 2,4-dichlorophenoxyacetic acid
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DOI：
10.1111/j.1365-313x.2006.02832.x
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发表时间：
2006-09-01
期刊：
影响因子：
7.2
通讯作者：
Oono, Yutaka
中科院分区：
文献类型：
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作者：
Rahman, Abidur;Nakasone, Akari;Oono, Yutaka
2，4-二氯苯氧乙酸（2，4-D）是吲哚-3-乙酸（IAA）的化学类似物，被广泛用作生长调节剂和外源生长素。由于2，4-D引起的生理和分子反应与IAA引起的反应相似，因此认为它们具有共同的反应途径。在这里，我们表明，一个突变体，抗生长素抗性1（aar 1），抗生长素对氯苯氧异丁酸（PCIB）的抗性筛选中确定的，是耐2，4-D，但响应像野生型IAA和1-萘乙酸根伸长和侧根诱导试验。通过分析DR 5：GUS和HS：AXR 3 NT-GUS背景中的GUS表达以及通过实时PCR定量IAA 11表达，证实了aar 1突变特异性地改变2，4-D响应性。这两个特征性的aar 1等位基因都具有多基因缺失;然而，通过转化两个等位基因中缺失的一个基因来恢复2，4-D响应性，并且通过使用RNAi构建体降低野生型中相同基因的表达来再现2，4-D抗性表型。该基因编码一种功能未知的小酸性蛋白（SMAP 1），存在于植物、动物和无脊椎动物中，但不存在于真菌或原核生物中。综上所述，这些结果表明，SMAP 1是一个调节组件，介导的2，4-D的反应，2，4-D和IAA的反应是部分不同的。
2,4-dichlorophenoxyacetic acid (2,4-D), a chemical analogue of indole-3-acetic acid (IAA), is widely used as a growth regulator and exogenous source of auxin. Because 2,4-D evokes physiological and molecular responses similar to those evoked by IAA, it is believed that they share a common response pathway. Here, we show that a mutant, antiauxin resistant1 (aar1), identified in a screen for resistance to the anti-auxin p-chlorophenoxy-isobutyric acid (PCIB), is resistant to 2,4-D, yet nevertheless responds like the wild-type to IAA and 1-napthaleneacetic acid in root elongation and lateral root induction assays. That the aar1 mutation alters 2,4-D responsiveness specifically was confirmed by analysis of GUS expression in the DR5:GUS and HS:AXR3NT-GUS backgrounds, as well as by real-time PCR quantification of IAA11 expression. The two characterized aar1 alleles both harbor multi-gene deletions; however, 2,4-D responsiveness was restored by transformation with one of the genes missing in both alleles, and the 2,4-D-resistant phenotype was reproduced by decreasing the expression of the same gene in the wild-type using an RNAi construct. The gene encodes a small, acidic protein (SMAP1) with unknown function and present in plants, animals and invertebrates but not in fungi or prokaryotes. Taken together, these results suggest that SMAP1 is a regulatory component that mediates responses to 2,4-D, and that responses to 2,4-D and IAA are partially distinct.