Differences in gene expression in whitefly associated with CYSDV-infected and virus-free melon, and comparison with expression in whiteflies fed on ToCV- and TYLCV-infected tomato

Navneet Kaur,Zhangjun Fei,Wenbo Chen,William M Wintermantel

doi:10.1186/s12864-019-5999-0

Abstract

BackgroundCucurbit yellow stunting disorder virus (CYSDV; genus Crinivirus, Closteroviridae) is transmitted in a semipersistent manner by the whitefly, Bemisia tabaci, and is efficiently transmitted by the widely prevalent B. tabaci cryptic species, MEAM1. In this study, we compared transcriptome profiles of B. tabaci MEAM1, after 24 h, 72 h and 7 days of acquisition feeding on melon plants infected with CYSDV (CYSDV-whiteflies) with those fed on virus-free melon, using RNA-Seq technology. We also compared transcriptome profiles with whiteflies fed on tomato plants separately infected with Tomato chlorosis virus (ToCV), a crinivirus closely related to CYSDV, and Tomato yellow leaf curl virus (TYLCV), a member of the genus Begomovirus, which has a distinctly different mode of transmission and their respective virus-free controls, to find common gene expression changes among viruliferous whiteflies feeding on different host plants infected with distinct (TYLCV) and related (CYSDV and ToCV) viruses.ResultsA total of 275 differentially expressed genes (DEGs) were identified in CYSDV-whiteflies, with 3 DEGs at 24 h, 221 DEGs at 72 h, and 51 DEGs at 7 days of virus acquisition. Changes in genes encoding orphan genes (54 genes), phosphatidylethanolamine-binding proteins (PEBP) (20 genes), and AAA-ATPase domain containing proteins (10 genes) were associated with the 72 h time point. Several more orphan genes (20 genes) were differentially expressed at 7 days. A total of 59 common DEGs were found between CYSDV-whiteflies and ToCV-whiteflies, which included 20 orphan genes and 6 lysosomal genes. A comparison of DEGs across the three different virus-host systems revealed 14 common DEGs, among which, eight showed similar and significant up-regulation in CYSDV-whiteflies at 72 h and TYLCV-whiteflies at 24 h, while down-regulation of the same genes was observed in ToCV-whiteflies at 72 h.ConclusionsDynamic gene expression changes occurred in CYSDV-whiteflies after 72 h feeding, with decreased gene expression changes associated with 7 days of CYSDV acquisition. Similarities in gene expression changes among CYSDV-whiteflies, ToCV-whiteflies and TYLCV-whiteflies suggest the possible involvement of common genes or pathways for virus acquisition and transmission by whiteflies, even for viruses with distinctly different modes of transmission.

Highlights

Cucurbit yellow stunting disorder virus (CYSDV; genus Crinivirus, Closteroviridae) is transmitted in a semipersistent manner by the whitefly, Bemisia tabaci, and is efficiently transmitted by the widely prevalent B. tabaci cryptic species, MEAM1
Differentially expressed gene (DEG) in whiteflies associated with feeding on CYSDVinfected melon plants To determine how global gene expression is differentially influenced in the whitefly when feeding on CYSDV infected melon plants as opposed to healthy melon plants, RNA-Seq was used to compare gene expression in whiteflies that had been fed on CYSDV-infected (‘CYSDV whiteflies’) or uninfected melon plants (‘virusfree [VF] whiteflies’) for acquisition access periods (AAP) of 24 h, 72 h, and 7 d
DEGs in whiteflies associated with feeding on CYSDVinfected melon plants Limited information is available with regard to the mechanism of how criniviruses associate with their whitefly vectors, the location of this association is believed to be within the anterior foregut based on studies involving Lettuce infectious yellows virus (LIYV) and B. tabaci NW [7,8,9]

Summary

Introduction

Cucurbit yellow stunting disorder virus (CYSDV; genus Crinivirus, Closteroviridae) is transmitted in a semipersistent manner by the whitefly, Bemisia tabaci, and is efficiently transmitted by the widely prevalent B. tabaci cryptic species, MEAM1. During virus acquisition by the whitefly vector, CYSDV is believed to associate with the anterior foregut of the whitefly through an association of the virus encoded minor coat protein (CPm) with as yet undetermined components of the insect. This is based on studies conducted on Lettuce infectious yellows virus (LIYV), another member of the genus Crinivirus [7,8,9]

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