Plants Pre-Infested With Viruliferous MED/Q Cryptic Species Promotes Subsequent Bemisia tabaci Infestation.

Xiaobin Shi,Huipeng Pan,Shaoli Wang,Qingjun Wu,Xuguo Zhou,Gong Chen,Yong Liu,Wen Xie,Youjun Zhang

doi:10.3389/fmicb.2018.01404

Abstract

The sweet potato whitefly, Bemisia tabaci, is one of the most invasive insect pests worldwide. The two most destructive whitefly cryptic species are MEAM1/B and MED/Q. Given that MED/Q has replaced MEAM1/B in China and the invasion of MED/Q has coincided with the outbreak of tomato yellow leaf curl virus (TYLCV), we hypothesize that pre-infestation with viruliferous B. tabaci will affect the subsequent host preferences. To test this hypothesis, we (1) conducted bioassays to compare the host preference of viruliferous and non-viruliferous MEAM1/B and MED/Q, respectively, on plants pre-infested with viruliferous and non-viruliferous MEAM1/B and MED/Q; (2) profiled plant volatiles using GC-MS; and (3) functionally characterized chemical cues could potentially modulate B. tabaci-TYLCV-tomato interactions, including ρ-cymene, thujene and neophytadiene, using a Y-tube olfactometer. As a result, plants pre-infested with MEAM1/B whiteflies carrying TYLCV or not, did not attract more or less B or Q whiteflies. Plants pre-infested with non-viruliferous MED/Q resisted MEAM1/B but did not affect MED/Q. However, plants pre-infested with viruliferous MED/Q attracted more whiteflies. Feeding of viruliferous MED/Q reduced the production of ρ-cymene, and induced thujene and neophytadiene. Functionally analyses of these plant volatiles show that ρ-cymene deters while neophytadiene recruits whiteflies. These combined results suggest that pre-infestation with viruliferous MED/Q promotes the subsequent whitefly infestation and induces plant volatile neophytadiene which recruits whiteflies.

Highlights

Plant virus spread and transmission is, at least partially, dependent on the virus–vector interaction, which can be modified by the virus to obtain an adaptive advantage (Blua and Perring, 1992)
Given the fact that MED/Q replaced MEAM1/B in China and the outbreak of virus is associated with the invasion of MED/Q, we hypothesize that B. tabaci will respond differently toward plants previously infested with viruliferous MEAM1/B and viruliferous MED/Q, respectively
The number of B. tabaci was similar on plants that were previously infested with non-viruliferous MEAM1/B and on undamaged plants (P = 0.404; Figure 1A)

Summary

INTRODUCTION

Plant virus spread and transmission is, at least partially, dependent on the virus–vector interaction, which can be modified by the virus to obtain an adaptive advantage (Blua and Perring, 1992). Given the fact that MED/Q replaced MEAM1/B in China and the outbreak of virus is associated with the invasion of MED/Q, we hypothesize that B. tabaci will respond differently toward plants previously infested with viruliferous MEAM1/B and viruliferous MED/Q, respectively. To test this hypothesis, we (1) conducted bioassays to compare the host preference of B. tabaci MEAM1/B and MED/Q on plants previously infested with viruliferous and non-viruliferous MEAM1/B and MED/Q, respectively; (2) profiled plant volatiles using GC-MS; and (3) functionally characterized ρ-cymene, thujene and neophytadiene, chemical cues that potentially modulate B. tabaci-TYLCV-tomato interactions using a Y-tube olfactometer. Compared to a mixture of ρ-cymene and thujene, a blend of ρ-cymene, thujene and neophytadiene attracted more B. tabaci, especially for MED/Q (either viruliferous or not) (Figure 4C)

RESULTS

Findings

MATERIALS AND METHODS