Glycolate Oxidase Modulates Reactive Oxygen Species-Mediated Signal Transduction during Nonhost Resistance in Nicotiana benthamiana and Arabidopsis
Glycolate Oxidase Modulates Reactive Oxygen Species-Mediated Signal Transduction during Nonhost Resistance in Nicotiana benthamiana and Arabidopsis
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DOI：
10.1105/tpc.111.093245
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发表时间：
2012-01-01
期刊：
影响因子：
11.6
通讯作者：
Mysore, Kirankumar S.
中科院分区：
文献类型：
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作者：
Rojas, Clemencia M.;Senthil-Kumar, Muthappa;Mysore, Kirankumar S.
与基因对基因抗病不同，非寄主抗病控制着对多种潜在病原菌的防御反应。为了确定与非寄主抗病相关的信号转导级联中的特定基因，我们利用病毒诱导的基因沉默筛选，并将过氧化物体酶乙醇酸氧化酶(GOx)鉴定为非寄主抗病的重要组成部分。Gox沉默的N.benthamiana和拟南芥Gox T-DNA插入突变体因非寄主抗性而受到损害。此外，拟南芥Gox突变体在接种引起超敏反应的非寄主病原体时，具有较低的H_2O_2积累，减少了痂蛋白的沉积，并减少了电解质渗漏。拟南芥Gox突变体的NADPH氧化酶活性没有受到影响，并且Gox突变体中编码NADPH氧化酶(呼吸爆发氧化酶同源)的基因的沉默并没有进一步增加对非寄主病原体的敏感性，这表明Gox的功能独立于NADPH氧化酶。在被检测的两个Gox突变体(hax2和gox3)中，与野生型植物相比，非寄主病原菌接种后几个防御相关基因的表达降低。在这里，我们表明，在基因对基因和非宿主抗性反应中，Gox是产生过氧化氢的另一种来源。
In contrast to gene-for-gene disease resistance, nonhost resistance governs defense responses to a broad range of potential pathogen species. To identify specific genes involved in the signal transduction cascade associated with nonhost disease resistance, we used a virus-induced gene-silencing screen in Nicotiana benthamiana, and identified the peroxisomal enzyme glycolate oxidase (GOX) as an essential component of nonhost resistance. GOX-silenced N. benthamiana and Arabidopsis thaliana GOX T-DNA insertion mutants are compromised for nonhost resistance. Moreover, Arabidopsis gox mutants have lower H2O2 accumulation, reduced callose deposition, and reduced electrolyte leakage upon inoculation with hypersensitive response-causing nonhost pathogens. Arabidopsis gox mutants were not affected in NADPH oxidase activity, and silencing of a gene encoding NADPH oxidase (Respiratory burst oxidase homolog) in the gox mutants did not further increase susceptibility to nonhost pathogens, suggesting that GOX functions independently from NADPH oxidase. In the two gox mutants examined (haox2 and gox3), the expression of several defense-related genes upon nonhost pathogen inoculation was decreased compared with wild-type plants. Here we show that GOX is an alternative source for the production of H2O2 during both gene-for-gene and nonhost resistance responses.