GH3 Auxin-Amido Synthetases Alter the Ratio of Indole-3-Acetic Acid and Phenylacetic Acid in Arabidopsis
GH3 Auxin-Amido Synthetases Alter the Ratio of Indole-3-Acetic Acid and Phenylacetic Acid in Arabidopsis
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DOI：
10.1093/pcp/pcz223
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发表时间：
2020-03-01
影响因子：
4.9
通讯作者：
Kasahara, Hiroyuki
中科院分区：
文献类型：
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作者：
Aoi, Yuki;Tanaka, Keita;Kasahara, Hiroyuki
生长素是第一个被发现的植物激素，对植物生长发育的许多方面都是必不可少的。吲哚-3-乙酸(IAA)是主要的生长素，通过生长素的极性运输在细胞间的通讯中起着关键作用。苯乙酸(PAA)是另一种不显示极性运动的天然生长素。虽然已有多种物种被证明能产生PAA，但其在植物中的生物合成、失活和生理意义还很不清楚。在这项研究中，我们证明了参与苄基硫代葡萄糖苷合成的CYP79A2基因的过表达显著增加了拟南芥中PAA的水平，并促进了侧根的形成。这与IAA水平的显著下降不谋而合。生长素代谢产物定量的结果表明，依赖于PAA的Gretchen Hagen3(GH3)基因的诱导促进了IAA的失活。类似地，通过吲哚-3-乙醛肟途径增加IAA合成，显著降低PAA水平。在野生型植物上应用每种生长素，也观察到了相同的IAA和PAA水平的调整。这些结果表明，GH3生长素-氨基合成酶可以改变植物生长发育中IAA和PAA的比例。
Auxin is the first discovered plant hormone and is essential for many aspects of plant growth and development. Indole-3-acetic acid (IAA) is the main auxin and plays pivotal roles in intercellular communication through polar auxin transport. Phenylacetic acid (PAA) is another natural auxin that does not show polar movement. Although a wide range of species have been shown to produce PAA, its biosynthesis, inactivation and physiological significance in plants are largely unknown. In this study, we demonstrate that overexpression of the CYP79A2 gene, which is involved in benzylglucosinolate synthesis, remarkably increased the levels of PAA and enhanced lateral root formation in Arabidopsis. This coincided with a significant reduction in the levels of IAA. The results from auxin metabolite quantification suggest that the PAA-dependent induction of GRETCHEN HAGEN 3 (GH3) genes, which encode auxin-amido synthetases, promote the inactivation of IAA. Similarly, an increase in IAA synthesis, via the indole-3-acetaldoxime pathway, significantly reduced the levels of PAA. The same adjustment of IAA and PAA levels was also observed by applying each auxin to wild-type plants. These results show that GH3 auxin-amido synthetases can alter the ratio of IAA and PAA in plant growth and development.