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Journal of Integrative Agriculture
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Salivary protein NlSP6935 that restricted to rice planthoppers is critical for insect survival and host defense regulation

Zelong Zhang*, Xiaojing Wang*, Xinye Xu, Tangbin Hu, Chuanxi Zhang, Haijian Huang#

State Key Laboratory for Quality and Safety of Agro-Products, Key Laboratory of Biotechnology in Plant Protection of MARA, Institute of Plant Virology, Ningbo University, Ningbo 315211, China 

 Highlights 

l NlSP6935 is a conserved salivary protein in rice planthoppers, essential for survival, feeding, and reproduction, independent of host plant resistance.

l Silencing NlSP6935 exerts effects on insect metabolism and cuticle formation, while its overexpression in plants suppresses H2O2 accumulation and terpenoid defenses.

l NlSP6935 functions as a dual effector, critical for both insect physiology and suppression of plant immune responses, highlighting its evolutionary role in host adaptation.

l Transgenic rice expressing NlSP6935 enhances planthopper attraction but fails to fully rescue RNAi-induced lethality, suggesting its indispensable endogenous function in insect biology.

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摘要  

唾液在植物-昆虫互作中扮演关键角色,然而其蛋白的功能多样性尚未被充分解析。本研究鉴定到一个唾液腺特异高表达的蛋白NlSP6935,该蛋白在取食水稻的三种稻飞虱中高度保守,但在取食竹子的近缘种中缺失。干扰NlSP6935表达可导致褐飞虱(Nilaparvata lugens)出现存活率下降、取食困难与繁殖不育等系列表型,且上述效应不依赖于寄主植物的抗性。功能分析表明,在本氏烟中瞬时表达NlSP6935能够抑制植物体内H₂O₂积累;而在水稻中过表达该蛋白则会抑制萜类化合物合成,并增强寄主对昆虫的吸引性。然而,在转基因水稻中表达NlSP6935仅能部分挽救由RNAi引起的褐飞虱死亡,说明该蛋白除调控植物防御外,对昆虫自身的生理功能也具有不可或缺的作用。本研究揭示了一个在稻飞虱生存与寄主适应中均起关键作用的唾液效应子,为探索新型害虫防控策略提供了理论依据与基因靶点。



Abstract  

Saliva plays a crucial role in mediating plant-insect interactions, yet the functional diversity of salivary proteins remains poorly understood. Here, we identify NlSP6935, a salivary gland-specific protein conserved among rice planthoppers but absent in bamboo-feeding relatives. Silencing NlSP6935 causes severe lethality, feeding impairment, and infertility in Nilaparvata lugens, independent of host plant resistance. Transient expression assays reveal that NlSP6935 suppresses H2O2 accumulation in plants, while overexpression in rice downregulates terpenoid biosynthesis and enhances host attractiveness. However, transgenic NlSP6935 plants only weakly rescue RNAi-induced lethality, demonstrating its dual role in insect physiology and plant defense suppression. Our findings reveal a novel effector essential for both planthopper survival and host adaptation, providing new insights into pest control strategies.

Keywords:  salivary protein       pest management              defense regulation              insect-plant interaction  
Online: 10 February 2026  
Fund: 

This project has received funding from the National Key Research and Development Program of China (2021YFD1401100), the National Natural Science Foundation of China (32422075 and 32572936), the Natural Science Foundation of Zhejiang Province, China (LDQ24C140001), and the Graduate Student Scientific Research and Innovation Project of Ningbo University (IF2025029).

About author:  #Correspondence Haijian Huang, E-mail: huanghaijian@nbu.edu.cn * These authors contribute equally to this study.

Cite this article: 

Zelong Zhang, Xiaojing Wang, Xinye Xu, Tangbin Hu, Chuanxi Zhang, Haijian Huang. 2026. Salivary protein NlSP6935 that restricted to rice planthoppers is critical for insect survival and host defense regulation. Journal of Integrative Agriculture, Doi:10.1016/j.jia.2026.02.013

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