The possible action mechanisms of indole-3-acetic acid methyl ester in Arabidopsis
The possible action mechanisms of indole-3-acetic acid methyl ester in Arabidopsis
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DOI：
10.1007/s00299-007-0458-9
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发表时间：
2008-03-01
影响因子：
6.2
通讯作者：
Qu, Li-Jia
中科院分区：
文献类型：
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作者：
Li, Linchuan;Hou, Xianhui;Qu, Li-Jia
我们之前报道过拟南芥吲哚-3-乙酸（IAA）-甲基转移酶-1（IAMT 1）催化必需植物激素IAA转化为甲基-IAA（MeIAA），并且IAMT 1在叶发育中发挥重要作用。在这里，我们提出了MeIAA在拟南芥中可能的作用机制。我们发现，MeIAA是更有力的比IAA在抑制下胚轴伸长和MeIAA和萘乙酸（NAA），但不IAA，拯救黑暗生长的aux 1下胚轴向地性缺陷。然而，MeIAA在抑制光生幼苗初生根伸长方面不如IAA有效，并且不能拯救aux 1的无重力向生根表型。MeIAA诱导侧根的能力强于IAA和NAA，挽救了aux 1幼苗的侧根缺陷表型。但是，其诱导根毛的能力弱于IAA和NAA，不能挽救aux 1幼苗的缺陷根毛表型。这些数据表明MeIAA是IAA的非活性形式。不同器官对MeIAA的敏感性不同可能是由于MeIAA酯酶的表达定位和转化MeIAA的能力不同所致。
We previously reported that Arabidopsis indole-3-acetic acid (IAA)-methyltransferase-1 (IAMT1) catalyzes the conversion of IAA, an essential phytohormone, to methyl-IAA (MeIAA) and that IAMT1 plays an important role in leaf development. Here, we present the possible mechanisms of action of MeIAA in Arabidopsis. We showed that MeIAA was more potent than IAA in the inhibition of hypocotyl elongation and that MeIAA and naphthalene-acetic acid (NAA), but not IAA, rescued the hypocotyl gravitropic defects in dark-grown aux1. However, MeIAA was less potent than IAA in the inhibition of primary root elongation in light-grown seedlings, and could not rescue the agravitropic root phenotype of aux1. MeIAA had a stronger capacity to induce lateral roots than both IAA and NAA and rescued the defective lateral root phenotype of aux1 seedlings. However, its capacity to induce root hairs was weaker than IAA and NAA and did not rescue the defective root hair phenotype of aux1 seedlings. These data indicate that MeIAA is an inactive form of IAA. The different sensitivities to MeIAA among different organs probably resulted from different expression localization and capacities of a putative MeIAA esterase to convert MeIAA to IAA.