Virus-mediated chemical changes in rice plants impact the relationship between non-vector planthopper Nilaparvata lugens Stål and its egg parasitoid Anagrus nilaparvatae Pang et Wang.

Xiaochan He,Guanchun Gao,Yujian Sun,Xusong Zheng,Junce Tian,Hongxing Xu,Xiaojun Zhou,Yajun Yang,Zhongxian Lu

doi:10.1371/journal.pone.0105373

Abstract

In order to clarify the impacts of southern rice black-streaked dwarf virus (SRBSDV) infection on rice plants, rice planthoppers and natural enemies, differences in nutrients and volatile secondary metabolites between infected and healthy rice plants were examined. Furthermore, the impacts of virus-mediated changes in plants on the population growth of non-vector brown planthopper (BPH), Nilaparvata lugens, and the selectivity and parasitic capability of planthopper egg parasitoid Anagrus nilaparvatae were studied. The results showed that rice plants had no significant changes in amino acid and soluble sugar contents after SRBSDV infection, and SRBSDV-infected plants had no significant effect on population growth of non-vector BPH. A. nilaparvatae preferred BPH eggs both in infected and healthy rice plants, and tended to parasitize eggs on infected plants, but it had no significant preference for infected plants or healthy plants. GC-MS analysis showed that tridecylic aldehyde occurred only in rice plants infected with SRBSDV, whereas octanal, undecane, methyl salicylate and hexadecane occurred only in healthy rice plants. However, in tests of behavioral responses to these five volatile substances using a Y-tube olfactometer, A. nilaparvatae did not show obvious selectivity between single volatile substances at different concentrations and liquid paraffin in the control group. The parasitic capability of A. nilaparvatae did not differ between SRBSDV-infected plants and healthy plant seedlings. The results suggested that SRBSDV-infected plants have no significant impacts on the non-vector planthopper and its egg parasitoid, A. nilaparvatae.

Highlights

The multi-trophic relationship involving plants, herbivorous insects, and natural enemies is the most basic component of most ecosystems
Mexican bean beetles (Epilachna varivestis) tended to choose those tissues infected with southern bean mosaic virus (SBMV) or bean pod mottle virus (BPMV), which were both caused by plant secondary compounds under viral infection [10]
To further understand the ecological impacts of the plant virus, this study investigated the effects of the changes in nutrients and volatile secondary metabolites of host plants after southern rice black-streaked dwarf virus (SRBSDV) infection on the population growth of non-vector brown planthopper (BPH), Nilaparvata lugens, as well as the selectivity and parasitic capability of its egg parasitoid Anagrus nilaparvatae

Summary

Introduction

The multi-trophic relationship involving plants, herbivorous insects, and natural enemies is the most basic component of most ecosystems. Viruses can affect the yield and quality of host plants, and the growth, physiological and biochemical changes as well as the ecological characteristics of arthropods serving as the vector. They can have direct or indirect effects on non-vector herbivorous arthropods and their natural enemies, potentially impacting entire agro-ecosystems [2,3,4]. The type and content of volatile substances in host plants changed, which in turn affected the behaviors of herbivorous arthropods and their natural enemies [9]. Many studies have focused on the interaction between viruses and host plants [6,12,13], and between viruses and vector insects [10,14,15,16]

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Results

Conclusion