A defect in glyoxysomal fatty acid β-oxidation reduces jasmonic acid accumulation in Arabidopsis
A defect in glyoxysomal fatty acid β-oxidation reduces jasmonic acid accumulation in Arabidopsis
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DOI：
10.1016/j.plaphy.2005.03.016
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发表时间：
2005-06-01
影响因子：
6.5
通讯作者：
Hildebrand, DF
中科院分区：
文献类型：
--
作者：
Afitlhile, MM;Fukushige, H;Hildebrand, DF
茉莉酸（JA）生物合成的最后步骤被认为涉及过氧化物酶体β-氧化，但这还没有得到直接证明。脂肪酸β-氧化的最后一步和关键步骤由3-酮脂酰-CoA硫解酶（KAT）催化（EC 2.3.1.16）。报道了拟南芥（Arabidopsis thaliana）生态型兰茨贝格直立突变体（Landsberg erecta）的一个突变体，该突变体缺乏功能性KAT蛋白，并且在乙醛酸体脂肪酸β-氧化中有缺陷。在这项研究中，发现突变体在其受伤的子叶和叶片中积累了降低水平的JA，而只有子叶积累了3-氧代-2-（α-2 '-烯基）-环戊烷-1-辛酸（OPC-8：0）。这表明硫解酶同工酶之一的缺陷损害OPC-8：0到JA的β-氧化。突变体具有足够的硫解酶活性的合成JA在未受伤的组织，但不是在受伤的组织。JA途径中催化β-氧化之前的步骤的酶的活性不被硫解酶蛋白中的突变改变。因此，突变体受伤组织中JA水平的降低归因于硫解酶蛋白的缺陷。(c)2005年，Elsevier SAS。版权所有
The final steps of jasmonic acid (JA) biosynthesis are thought to involve peroxisomal (3-oxidation, but this has not been directly demonstrated. The last and key step in fatty acid (3-oxidation is catalyzed by 3-ketoacyl-CoA thiolase (KAT) (EC 2.3.1.16). A mutant of Arabidopsis thaliana ecotype Landsberg erecta, which lacks a functional KAT protein and is defective in glyoxysomal fatty acid (3-oxidation has been reported. In this study, the mutant was found to accumulate reduced level of JA in both its wounded cotyledons and leaves, while only the cotyledons accumulate 3-oxo-2-(pent-2'-enyl)-cyclopentane-1-octanoic acid (OPC-8:0). This indicates that a defect in one of the thiolase isoenzymes impairs (3-oxidation of OPC-8:0 to JA. The mutant had sufficient thiolase activity for the synthesis of JA in the unwounded but not in the wounded tissues. Activities of the enzymes in the JA pathway that catalyze the steps, which precede (3-oxidation were not altered by the mutation in a thiolase protein. Thus, reduced levels of JA in the wounded tissues of the mutant were attributed to the defect in a thiolase protein. (c) 2005 Elsevier SAS. All rights reserved