Molecular cloning and functional analysis of the pepper resistance gene Me3 to root-knot nematode
Yang Liu, Hongyi Cao, Jian Ling, Yuhong Yang, Yan Li, Bingyan Xie, Jianlong Zhao, Zhenchuan Mao
Abstract
Root-knot nematodes (RKNs) cause severe diseases in peppers annually around the world. In pepper, the Me3 gene provides a heat-stable and broad-spectrum resistance to RKNs. In this study, several simple sequence repeat (SSR) markers and insertion/deletion (InDel) markers were developed to fine map the Me3 gene. Analysis of 2272 individuals (F 2 progenies) revealed that Me3 was located in a 45-kb DNA region between markers SSR784 and SSR339, in which there were three candidate genes. Among them, as a novel nucleotide binding site and leucine rich repeat (NBS-LRR) family gene , the DNA sequence of Capana09g000163 of pepper line ‘HDA149’ was 6348 bp in length, with a 2802-bp open reading frame encoding 933 amino acids , including NB-ARC and LRR domains. Tobacco transient expression assays demonstrated that expression of Capana09g000163 triggered a hypersensitive response (HR) in Nicotiana benthamiana leaves. Subcellular localization results showed that the Capana09g000163 protein was localized in the cell nucleus . Ectopic expression of Capana09g000163 in Arabidopsis significantly increased resistance against Meloidogyne incognita compared with the wild-type (WT) Arabidopsis . Furthermore, M . incognita was almost unable to develop in transgenic Arabidopsis expressing Capana09g000163 . Taken together, we cloned the Me3 gene and verified that it induced resistance against M . incognita with the methods of map-based cloning and transgenic technology, which may be of great significance to pepper breeding for resistance against RKNs.