Transcriptome analysis of host-associated differentiation in Bemisia tabaci (Hemiptera: Aleyrodidae).

Wen Xie,Shaoli Wang,Youjun Zhang,Xuguo Zhou,Xiaoguo Jiao,Qingjun Wu,Litao Guo

doi:10.3389/fphys.2014.00487

Abstract

Host-associated differentiation is one of the driving forces behind the diversification of phytophagous insects. In this study, host induced transcriptomic differences were investigated in the sweetpotato whitefly Bemisia tabaci, an invasive agricultural pest worldwide. Comparative transcriptomic analyses using coding sequence (CDS), 5′ and 3′ untranslated regions (UTR) showed that sequence divergences between the original host plant, cabbage, and the derived hosts, including cotton, cucumber and tomato, were 0.11–0.14%, 0.19–0.26%, and 0.15–0.21%, respectively. In comparison to the derived hosts, 418 female and 303 male transcripts, respectively, were up-regulated in the original cabbage strain. Among them, 17 transcripts were consistently up-regulated in both female and male whiteflies originated from the cabbage host. Specifically, two ESTs annotated as Cathepsin B or Cathepsin B-like genes were significantly up-regulated in the original cabbage strain, representing a transcriptomic response to the dietary challenges imposed by the host shifting. Results from our transcriptome analysis, in conjunction with previous reports documenting the minor changes in their reproductive capacity, insecticide susceptibility, symbiotic composition and feeding behavior, suggest that the impact of host-associated differentiation in whiteflies is limited. Furthermore, it is unlikely the major factor contributing to their rapid range expansion/invasiveness.

Highlights

Host-associated differentiation (HAD) in insects, occurring mainly in sympatric populations, is generally considered to be an adaptation to different habitats and resources
Using electrical penetration graph technology to quantitatively measure the feeding behavior, we showed that B. tabaci maintained on their original cabbage host outperformed whiteflies derived from cucumber and tomato (Liu et al, 2013)
We examined the sequence divergence between a B. tabaci population originated from a cabbage host and three other whitefly populations which have been subjected to the long-term isolation in cotton, cucumber and tomato, respectively, for multiple generations

Summary

INTRODUCTION

Host-associated differentiation (HAD) in insects, occurring mainly in sympatric populations, is generally considered to be an adaptation to different habitats and resources. Originated from a B. tabaci B population collected in 2004, we established several laboratory whitefly strains feeding exclusively on their original host, cabbage, and the derived hosts, cucumber, tomato, cotton and poinsettia After maintaining on their respective hosts for 3–5 years, these whitefly strains displayed few variations in their life history traits (Lou et al, 2005; Fu et al, 2008), insecticide susceptibility (Xie et al, 2011), symbiotic contents (Pan et al, 2013) and feeding behavior (Liu et al, 2013). Results from the comparative transcriptomic profiling will shed light on the molecular mechanisms underlying the HAD, and contribute to our understanding of the host-induced evolution in this emerging global invasive pest

MATERIALS AND METHODS

AND DISCUSSION

Findings

CONCLUSIONS