Overexpression of salicylic acid carboxyl methyltransferase reduces salicylic acid-mediated pathogen resistance in Arabidopsis thaliana
Overexpression of salicylic acid carboxyl methyltransferase reduces salicylic acid-mediated pathogen resistance in Arabidopsis thaliana
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DOI：
10.1007/s11103-006-9123-x
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发表时间：
2007-05-01
影响因子：
5.1
通讯作者：
Do Choi, Yang
中科院分区：
文献类型：
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作者：
Koo, Yeon Jong;Kim, Myeong Ae;Do Choi, Yang
我们从水稻中克隆了一个水杨酸/苯甲酸羧甲基转移酶基因OsBSMT 1。通过在大肠杆菌中表达该基因获得的重组OsBSMT 1蛋白在与水杨酸（SA）、苯甲酸（BA）和脱S-甲基苯并（1，2，3）噻二唑-7-硫代甲酸（dSM-BTH）反应时显示出羧基甲基转移酶活性，分别生成水杨酸甲酯（梅萨）、苯甲酸甲酯（MeBA）和dSM-BTH甲酯（MeBTH）。与野生型植物相比，过表达OsBSMT 1的转基因拟南芥积累了相当高水平的梅萨和MeBA，其中一些被蒸发到环境中。在感染细菌病原体假单胞菌或真菌病原体Golovinomyces orontii后，转基因植物未能积累SA及其葡萄糖苷（SAG），变得比野生型植物更容易患病。OsBSMT 1过表达的拟南芥在SA或G. orontii。值得注意的是，与转基因植物一起孵育足以在邻近的野生型植物中引发PR-1诱导。总之，我们的研究结果表明，在没有SA的情况下，单独的梅萨不能诱导防御反应，但它作为一个空中信号植物对植物的通信。我们还发现茉莉酸（JA）诱导AtBSMT 1，这可能通过耗尽植物中的SA库而对SA信号通路产生拮抗作用。
We cloned a salicylic acid/benzoic acid carboxyl methyltransferase gene, OsBSMT1, from Oryza sativa. A recombinant OsBSMT1 protein obtained by expressing the gene in Escherichia coli exhibited carboxyl methyltransferase activity in reactions with salicylic acid (SA), benzoic acid (BA), and de-S-methyl benzo(1,2,3)thiadiazole-7-carbothioic acid (dSM-BTH), producing methyl salicylate (MeSA), methyl benzoate (MeBA), and methyl dSM-BTH (MeBTH), respectively. Compared to wild-type plants, transgenic Arabidopsis overexpressing OsBSMT1 accumulated considerably higher levels of MeSA and MeBA, some of which were vaporized into the environment. Upon infection with the bacterial pathogen Pseudomonas syringae or the fungal pathogen Golovinomyces orontii, transgenic plants failed to accumulate SA and its glucoside (SAG), becoming more susceptible to disease than wild-type plants. OsBSMT1-overexpressing Arabidopsis showed little induction of PR-1 when treated with SA or G. orontii. Notably, incubation with the transgenic plant was sufficient to trigger PR-1 induction in neighboring wild-type plants. Together, our results indicate that in the absence of SA, MeSA alone cannot induce a defense response, yet it serves as an airborne signal for plant-to-plant communication. We also found that jasmonic acid (JA) induced AtBSMT1, which may contribute to an antagonistic effect on SA signaling pathways by depleting the SA pool in plants.