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Secretome Analysis and In Planta Expression of Salivary Proteins Identify Candidate Effectors from the Brown Planthopper Nilaparvata lugens

Authors :
Huiying Wang
Bingfang Liu
Weiwei Rao
Chunxue Xu
Shaojie Shi
Xiaohong Zheng
Yan Wu
Jianping Guo
Weihua Jiang
Jin Huang
Liang Hu
Qin Guo
Guangcun He
Xinxin Shangguan
Zhizheng Wang
Di Wu
Source :
Molecular Plant-Microbe Interactions®. 32:227-239
Publication Year :
2019
Publisher :
Scientific Societies, 2019.

Abstract

The brown planthopper (BPH), Nilaparvata lugens (Stål), is a phloem sap-feeding insect. During feeding on rice plants, BPH secretes salivary proteins with potential effector functions, which may play a critical role in the plant–insect interactions. However, a limited number of BPH effector proteins have been identified to date. Here, we sequenced the salivary gland transcriptomes of five BPH populations and subsequently established a N. lugens secretome consisting of 1,140 protein-encoding genes. Secretome analysis revealed the presence of both conserved and rapidly evolving salivary proteins. A screen for potential effectors that elicit responses in the plant was performed via the transient expression analysis of 64 BPH salivary proteins in Nicotiana benthamiana leaves and rice protoplasts. The salivary proteins Nl12, Nl16, Nl28, and Nl43 induced cell death, whereas Nl40 induced chlorosis and Nl32 induced a dwarf phenotype in N. benthamiana, indicating effector properties of these proteins. Ectopic expression of the six salivary proteins in N. benthamiana upregulated expression of defense-related genes and callose deposition. Tissue expression analysis showed a higher expression level of the six candidate effectors in salivary glands than in other tissues. Subcellular localization and analysis of the domain required for cell death showed a diverse structure of the six effectors. Nl28, Nl40, and Nl43 are N. lugens specific; in contrast, Nl12, Nl16, and Nl32 are conserved among insects. The Nl40 family has numerous isoforms produced by alternative splicing, exemplifying rapid evolution and expansion of effector proteins in the BPH. Our results suggest a potential large effector repertoire in BPH and a higher level of effector conservation exist in BPH compared with that in plant pathogens.

Details

ISSN :
19437706 and 08940282
Volume :
32
Database :
OpenAIRE
Journal :
Molecular Plant-Microbe Interactions®
Accession number :
edsair.doi.dedup.....5c2f55e6739b30a570979039a6eb5b90
Full Text :
https://doi.org/10.1094/mpmi-05-18-0122-r