Laboratory of Phytopathology, Wageningen University, 6708 PB, Wageningen, the Netherlands; Centre for BioSystems Genomics, 6700 AB, Wageningen, the Netherlands.
Mol Plant Pathol. 2014 Jan;15(1):109-17. doi: 10.1111/mpp.12071. Epub 2013 Sep 10.
The tomato receptor-like protein (RLP) Ve1 mediates resistance to the vascular fungal pathogen Verticillium dahliae. To identify the proteins required for Ve1 function, we transiently expressed and immunopurified functional Ve1-enhanced green fluorescent protein (eGFP) from Nicotiana benthamiana leaves, followed by mass spectrometry. This resulted in the identification of peptides originating from the endoplasmic reticulum (ER)-resident chaperones HSP70 binding proteins (BiPs) and a lectin-type calreticulin (CRT). Knock-down of the different BiPs and CRTs in tomato resulted in compromised Ve1-mediated resistance to V. dahliae in most cases, showing that these chaperones play an important role in Ve1 functionality. Recently, it has been shown that one particular CRT is required for the biogenesis of the RLP-type Cladosporium fulvum resistance protein Cf-4 of tomato, as silencing of CRT3a resulted in a reduced pool of complex glycosylated Cf-4 protein. In contrast, knock-down of the various CRTs in N. benthamiana or N. tabacum did not result in reduced accumulation of mature complex glycosylated Ve1 protein. Together, this study shows that the BiP and CRT ER chaperones differentially contribute to Cf-4- and Ve1-mediated immunity.
番茄类受体样蛋白（RLP）Ve1 介导对维管束真菌病原体黄萎病菌的抗性。为了鉴定参与 Ve1 功能的蛋白质，我们从烟草原生质体中瞬时表达和免疫纯化了功能 Ve1-增强型绿色荧光蛋白（eGFP），随后进行了质谱分析。这导致鉴定出了源自内质网（ER）驻留伴侣 HSP70 结合蛋白（BiPs）和凝集素型钙网蛋白（CRT）的肽。在番茄中敲低不同的 BiPs 和 CRT 会导致大多数情况下 Ve1 介导的对黄萎病菌的抗性受损，表明这些伴侣蛋白在 Ve1 功能中起着重要作用。最近，已经表明一种特定的 CRT 是番茄 RLP 型炭疽病菌抗性蛋白 Cf-4 生物发生所必需的，因为 CRT3a 的沉默导致成熟的复合糖基化 Cf-4 蛋白池减少。相比之下，在烟草原生质体或烟草中敲低各种 CRT 不会导致成熟的复合糖基化 Ve1 蛋白积累减少。总之，这项研究表明 BiP 和 CRT ER 伴侣蛋白对 Cf-4 和 Ve1 介导的免疫有不同的贡献。
