Accumulation of hydroxycinnamic acid amides induced by pathogen infection and identification of agmatine coumaroyltransferase in Arabidopsis thaliana
Accumulation of hydroxycinnamic acid amides induced by pathogen infection and identification of agmatine coumaroyltransferase in Arabidopsis thaliana
复制标题
DOI：
10.1007/s00425-009-0960-0
复制
发表时间：
2009-08-01
期刊：
影响因子：
4.3
通讯作者：
Nishioka, Takaaki
中科院分区：
文献类型：
--
作者：
Muroi, Atsushi;Ishihara, Atsushi;Nishioka, Takaaki
羟基肉桂酰胺 (HCAA) 是参与植物防御病原体的次生代谢物。在这里，我们报告了在感染芸苔属链格孢菌的拟南芥莲座叶中首次鉴定出 HCAA、对香豆酰精胺、阿魏酰精胺、对香豆酰腐胺和阿魏酰腐胺，并将 At5g61160 指定为催化最后一个过程的胍丁胺香豆酰转移酶 (AtACT)。 HCAA 生物合成中的反应。使用假定的标记前体进行喂养实验表明，四种 HCAA 是由羟基肉桂酸和胍丁胺或腐胺合成的。 AtACT 基因功能是通过对不积累 HCAA 的突变体的分析来确定的。在野生型拟南芥中，AtACT 转录本显着增加以响应芸苔菌感染。通过使用大肠杆菌中表达的重组 AtACT，在体外证实了催化 HCAA 合成的酶活性。 Atact 突变体易受芸苔菌感染，表明 HCAA 负责防御拟南芥中的病原体。
Hydroxycinnamic acid amides (HCAAs) are secondary metabolites involved in the defense of plants against pathogens. Here, we report the first identification of HCAAs, p-coumaroylagmatine, feruloylagmatine, p-coumaroylputrescine and feruloylputrescine, in Arabidopsis thaliana rosette leaves infected with Alternaria brassicicola and the assignment of At5g61160 as the agmatine coumaroyltransferase (AtACT) that catalyzes the last reaction in the biosynthesis of the HCAAs. Feeding experiments with putative labeled precursors revealed that the four HCAAs were synthesized from hydroxycinnamic acids and agmatine or putrescine. AtACT gene function was identified from an analysis of a mutant that did not accumulate HCAAs. In wild-type Arabidopsis, AtACT transcripts markedly increased in response to A. brassicicola infection. Enzymatic activity that catalyzes the synthesis of the HCAAs was confirmed in vitro by using a recombinant AtACT expressed in Escherichia coli. The Atact mutant was susceptible to infection by A. brassicicola, indicating that HCAAs are responsible for defense against pathogens in A. thaliana.