Department of Nematology, University of California, Riverside, CA 92521, USA.
Plant J. 2011 Aug;67(3):459-71. doi: 10.1111/j.1365-313X.2011.04609.x. Epub 2011 Jun 6.
The plant receptor-like kinase somatic embryogenesis receptor kinase 3 (SERK3)/brassinosteroid insensitive 1-associated kinase 1 (BAK1) is required for pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI). Here we show that a distinct member of the SERK family, SERK1, is required for the full functioning of Mi-1, a nucleotide binding leucine-rich repeat (NB-LRR) resistance protein. Mi-1 confers resistance to Meloidogyne spp. (root-knot nematodes, RKNs) and three phloem-feeding insects, including Macrosiphum euphorbiae (potato aphid). SERK1 was identified in a tobacco rattle virus (TRV)-based virus-induced gene silencing (VIGS) screen in Nicotiana benthamiana. The screen was based on the suppression of a pest-independent hypersensitive response triggered by a constitutively active form of Mi-1, Mi-DS4. To assess the role of SERK1 in Mi-1-mediated resistance, Solanum lycopersicum (tomato) SlSERK genes were cloned. Three SlSERK members were identified with homologies to Arabidopsis AtSERK1 or AtSERK3/BAK1, and were named SlSERK1, SlSERK3A and SlSERK3B. SlSERK1 is ubiquitously expressed in tomato. Reducing SlSERK1 transcript levels in resistant plants, using gene-specific TRV-SERK1 VIGS, revealed a role for SlSERK1 in Mi-1-mediated resistance to potato aphids, but not to RKNs. In addition, Mi-1-dependent SlWRKY72 gene regulation was compromised in SlSERK1-silenced plants, placing SlSERK1 in the Mi-1 signaling pathway. Silencing SlSERK1 in a susceptible tomato background did not reduce the susceptibility to aphids, indicating that SlSERK1 is unlikely to be an essential virulence target. SlSERK1 is an active kinase, mainly localized at the plasma membrane. This work identifies a critical early component of Mi-1 signaling, and demonstrates a role for SlSERK1 in NB-LRR-mediated immunity.
植物类受体激酶体细胞胚发生受体激酶 3（SERK3）/油菜素内酯不敏感 1 相关激酶 1（BAK1）是植物病原体相关分子模式（PAMP）触发的免疫（PTI）所必需的。在这里，我们表明 SERK 家族的一个独特成员 SERK1，是核苷酸结合亮氨酸重复（NB-LRR）抗性蛋白 Mi-1 充分发挥功能所必需的。Mi-1 赋予对 Meloidogyne spp.（根结线虫，RKN）和三种韧皮部取食昆虫，包括 Macrosiphum euphorbiae（马铃薯蚜虫）的抗性。SERK1 是在 Nicotiana benthamiana 中基于烟草脆裂病毒（TRV）的病毒诱导基因沉默（VIGS）筛选中鉴定的。该筛选基于由组成型激活形式的 Mi-1 触发的一种非害虫诱导的超敏反应的抑制，Mi-DS4。为了评估 SERK1 在 Mi-1 介导的抗性中的作用，克隆了 Solanum lycopersicum（番茄）SlSERK 基因。鉴定出 3 个 SlSERK 成员与拟南芥 AtSERK1 或 AtSERK3/BAK1 同源，并分别命名为 SlSERK1、SlSERK3A 和 SlSERK3B。SlSERK1 在番茄中广泛表达。使用基因特异性 TRV-SERK1 VIGS 降低抗性植物中的 SlSERK1 转录水平，表明 SlSERK1 在 Mi-1 介导的对马铃薯蚜虫的抗性中起作用，但对 RKN 不起作用。此外，在 SlSERK1 沉默的植物中，Mi-1 依赖性 SlWRKY72 基因调控受到损害，这表明 SlSERK1 位于 Mi-1 信号通路中。在易感番茄背景下沉默 SlSERK1 不会降低对蚜虫的敏感性，这表明 SlSERK1 不太可能是一个必需的毒力靶标。SlSERK1 是一种活性激酶，主要定位于质膜。这项工作鉴定了 Mi-1 信号传导的一个关键早期组成部分，并证明了 SlSERK1 在 NB-LRR 介导的免疫中的作用。
