The LeATL6-associated ubiquitin/proteasome system may contribute to fungal elicitor-activated defense response via the jasmonic acid-dependent signaling pathway in tomato
The LeATL6-associated ubiquitin/proteasome system may contribute to fungal elicitor-activated defense response via the jasmonic acid-dependent signaling pathway in tomato
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DOI：
10.1094/mpmi-20-0072
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发表时间：
2007-01-01
影响因子：
3.5
通讯作者：
Takahashi, Hideki
中科院分区：
文献类型：
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作者：
Hondo, Daisuke;Hase, Shu;Takahashi, Hideki
用生防剂寡头腐霉的细胞壁蛋白片段(CWP)激发子诱导番茄根表达LeATL6，LeATL6是拟南芥ATL6的同源基因，编码一个环H2指蛋白。LeATL6蛋白在大肠杆菌中以麦芽糖结合蛋白(MBP)的形式表达，并与泛素、泛素激活酶EL和泛素结合酶E2共同作用，催化泛素转移到MBP部分，这表明LeATL6代表泛素连接酶E3。在茉莉酸(JA)介导的信号通路受损的JAR-1突变体番茄细胞中，激发子处理也能诱导LeATL6的表达，但在激发子处理的JAR-1突变体中，分别编码蛋白酶抑制因子II和I的基本PR-6和TPI-1基因不能诱导JA依赖性的表达。此外，在花椰菜花叶病毒35S启动子控制下的LeATL6的瞬时过表达诱导了野生番茄中PR6和TPI-1的基本表达，但在JAR-1突变体中没有。相反，LeATL6过表达不能激活野生型番茄中对水杨酸反应的酸性PR-1和PR-2启动子。这些结果表明，激发子响应型LeATL6基因可能调控依赖茉莉酸的番茄碱性PR6和TPI-1基因的表达。在植物中，LeATL6相关的泛素/蛋白酶体系统可能通过JA依赖的信号通路参与激发子激活的防御反应。
The expression of LeATL6, an ortholog of Arabidopsis ATL6 that encodes a RING-H2 finger protein, was induced in tomato roots treated with a cell wall protein fraction (CWP) elicitor of the biocontrol agent Pythium oligaudrum. The LeATL6 protein was expressed as a fusion protein with a maltose-binding protein (MBP) in Escherichia coli, and it catalyzed the transfer of ubiquitin to the MBP moiety on incubation with ubiquitin, the ubiquitin-activating enzyme El, and the ubiquitin-conjugating enzyme E2; this indicated that LeATL6 represents ubiquitin ligase E3. LeATL6 expression also was induced by elicitor treatment of jail-1 mutant tomato cells in which the jasmonic acid (JA)-mediated signaling pathway was impaired; however, JA-dependent expression of the basic PR-6 and TPI-1 genes that encode proteinase inhibitor II and I, respectively, was not induced in elicitor-treated jail-1 mutants. Furthermore, transient overexpression of LeATL6 under the control of the Cauliflower mosaic virus 35S promoter induced the basic PR6 and TPI-1 expression in wild tomato but not in the jail-1 mutant. In contrast, LeATL6 overexpression did not activate salicylic acid-responsive acidic PR-1 and PR-2 promoters in wild tomato. These results indicated that elicitor-responsive LeATL6 probably regulates JA-dependent basic PR6 and TPI-1 gene expression in tomato. The LeATL6-associated ubiquitin/proteasome system may contribute to elicitor-activated defense responses via a JA-dependent signaling pathway in plants.