Nicotiana benthamiana gp91phox homologs NbrbohA and NbrbohB participate in H2O2 accumulation and resistance to Phytophthora infestans
Nicotiana benthamiana gp91phox homologs NbrbohA and NbrbohB participate in H2O2 accumulation and resistance to Phytophthora infestans
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DOI：
10.1105/tpc.008680
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发表时间：
2003-03-01
期刊：
影响因子：
11.6
通讯作者：
Doke, N
中科院分区：
文献类型：
--
作者：
Yoshioka, H;Numata, N;Doke, N
活性氧（AOS）负责触发植物的防御反应。呼吸爆发氧化酶同系物（rboh 基因）与 AOS 的产生有关。我们从本塞姆氏烟草叶子中分离出了两个 rboh cDNA，NbrbohA 和 NbrbohB。 NbrbohA 以低水平组成型表达，并且在对照叶渗透的机械胁迫后转录本增加，而 NbrbohB 是由来自马铃薯病原体致病疫霉的蛋白激发子 INF1 特异性诱导的。我们使用病毒诱导的基因沉默 (VIGS) 检查了 Nbrboh 基因在 AOS 生成和过敏反应 (HR) 中的功能。 VIGS 表明这两个基因都是 H2O2 积累和抗疫霉所必需的。 Nbrboh 基因的 VIGS 还导致 INF1 引起的 HR 细胞死亡减少和延迟。我们进一步证明，通过过度表达有丝分裂原激活蛋白激酶激酶 MEKDD 的组成型活性突变体来诱导 HR 样细胞死亡，会受到 NbrbohB 的 VIGS 的影响。我们发现 MEKDD 诱导 NbrbohB 但不诱导 NbrbohA。这项工作为丝裂原激活蛋白激酶级联参与 rboh 基因的调节提供了遗传证据。
Active oxygen species (AOS) are responsible for triggering defense responses in plants. Respiratory burst oxidase homologs (rboh genes) have been implicated in AOS generation. We have isolated two rboh cDNAs, NbrbohA and NbrbohB, from Nicotiana benthamiana leaves. NbrbohA was expressed constitutively at a low level and the transcripts were increased after mechanical stress of control leaf infiltration, whereas NbrbohB was induced specifically by the protein elicitor INF1 from the potato pathogen Phytophthora infestans. We examined the function of the Nbrboh genes in AOS generation and in the hypersensitive response (HR) using virus-induced gene silencing (VIGS). VIGS indicated that both genes are required for H2O2 accumulation and for resistance to Phytophthora. VIGS of Nbrboh genes also led to a reduction and delay of HR cell death caused by INF1. We further demonstrate that the induction of HR-like cell death by overexpression of a constitutively active mutant of a mitogen-activated protein kinase kinase, MEKDD, is compromised by VIGS of NbrbohB. We found that MEKDD induced NbrbohB but not NbrbohA. This work provides genetic evidence for the involvement of a mitogen-activated protein kinase cascade in the regulation of rboh genes.