Analysis of the Transcriptional Differences between Indigenous and Invasive Whiteflies Reveals Possible Mechanisms of Whitefly Invasion

Yong-Liang Wang,Yu-Jun Wang,Gen-Hong Yan,Xiao-Wei Wang,Jun-Bo Luan,Shu-Sheng Liu,Christian Schönbach

doi:10.1371/journal.pone.0062176

Abstract

BackgroundThe whitefly Bemisa tabaci is a species complex of more than 31 cryptic species which include some of the most destructive invasive pests of crops worldwide. Among them, Middle East-Asia Minor 1 (MEAM1) and Mediterranean have invaded many countries and displaced the native whitefly species. The successful invasion of the two species is largely due to their wide range of host plants, high resistance to insecticides and remarkable tolerance to environmental stresses. However, the molecular differences between invasive and indigenous whiteflies remain largely unknown.Methodology/Principal FindingsHere the global transcriptional difference between the two invasive whitefly species (MEAM1, MED) and one indigenous whitefly species (Asia II 3) were analyzed using the Illumina sequencing. Our analysis indicated that 2,422 genes between MEAM1 and MED; 3,073 genes between MEAM1 and Asia II 3; and 3,644 genes between MED and Asia II 3 were differentially expressed. Gene Ontology enrichment analysis revealed that the differently expressed genes between the invasive and indigenous whiteflies were significantly enriched in the term of ‘oxidoreductase activity’. Pathway enrichment analysis showed that carbohydrate, amino acid and glycerolipid metabolisms were more active in MEAM1 and MED than in Asia II 3, which may contribute to their differences in biological characteristics. Our analysis also illustrated that the majority of genes involved in ‘drug metabolic pathway’ were expressed at a higher level in MEAM1 and MED than in Asia II 3. Taken together, these results revealed that the genes related to basic metabolism and detoxification were expressed at an elevated level in the invasive whiteflies, which might be responsible for their higher resistance to insecticides and environmental stresses.Conclusions/SignificanceThe extensive comparison of MEAM1, MED and Asia II 3 gene expression may serve as an invaluable resource for revealing the molecular mechanisms underlying their biological differences and the whitefly invasion.

Highlights

The whitefly Bemisia tabaci (Gennadius) (Aleyrodidae: Hemiptera) is a species complex consisting of at least 31 genetically diverse but morphologically indistinguishable cryptic species [1,2,3,4,5,6,7]
Similar distributions of tag numbers were found at different categories of tag expression levels, suggesting that little bias exists in the construction of libraries from these three whitefly species (Figure S1)
To identify the orthologous genes among the three species, which can be used for comparing gene expression, the 33,393 common distinct tags of Middle East-Asia Minor 1 (MEAM1), MED and Asia II 3 sequencing libraries were filtered out and mapped to the MED, MEAM1 and Asia II 3 transcriptomes sequentially according to the procedures in Figure 1

Summary

Introduction

The whitefly Bemisia tabaci (Gennadius) (Aleyrodidae: Hemiptera) is a species complex consisting of at least 31 genetically diverse but morphologically indistinguishable cryptic species (hereafter species) [1,2,3,4,5,6,7]. To identify the orthologous genes among the three species, which can be used for comparing gene expression, the 33,393 common distinct tags of MEAM1, MED and Asia II 3 sequencing libraries were filtered out and mapped to the MED, MEAM1 and Asia II 3 transcriptomes sequentially according to the procedures in Figure 1 (see Materials and Methods for details).

Results

Conclusion