Conservation of transcriptional elements in the obligate symbiont of the whitefly Bemisia tabaci.

Dan-Tong Zhu,Fei-Xue Ban,Xiao-Wei Wang,Yin-Quan Liu,Hua-Ling Wang,Chi Zou

doi:10.7717/peerj.7477

Abstract

BackgroundBacterial symbiosis is widespread in arthropods, especially in insects. Some of the symbionts undergo a long-term co-evolution with the host, resulting in massive genome decay. One particular consequence of genome decay is thought to be the elimination of transcriptional elements within both the coding region and intergenic sequences. In the whitefly Bemisia tabaci species complex, the obligate symbiont Candidatus Portiera aleyrodidarum is of vital importance in nutrient provision, and yet little is known about the regulatory capacities of it.MethodsPortiera genomes of two whitefly species in China were sequenced and assembled. Gene content of these two Portiera genomes was predicted, and then subjected to Kyoto Encyclopedia of Genes and Genomes pathway analysis. Together with two other Portiera genomes from whitefly species available previously, four Portiera genomes were utilized to investigate regulatory capacities of Portiera, focusing on transcriptional elements, including genes related with transcription and functional elements within the intergenic spacers.ResultsComparative analyses of the four Portiera genomes of whitefly B. tabaci indicate that the obligate symbionts Portiera is similar in different species of whiteflies, in terms of general genome features and possible functions in the biosynthesis of essential amino acids. The screening of transcriptional factors suggests compromised ability of Portiera to regulate the essential amino acid biosynthesis pathways. Meanwhile, thermal tolerance ability of Portiera is indicated with the detection of a σ32 factor, as well as two predicted σ32 binding sites. Within intergenic spacers, functional elements are predicted, including 37 Shine-Dalgarno sequences and 34 putative small RNAs.

Highlights

Over the last two decades, multiple functions of microbiota have been investigated, from nutrition provision to reproduction (Stouthamer, Breeuwer & Hurst, 1999; Moran, McCutcheon & Nakabachi, 2008; Akman & Douglas, 2009)
To focus on the Portiera from the whitefly B. tabaci only, 227 core-genes were determined by OrthoMCL among the four Portiera genomes from whitefly B. tabaci, and subjected to BLASTP (E-value
The classification of Portiera was evidenced by the phylogenetic tree, where four Portiera genomes from B. tabaci obviously formed two different clades, in coincidence with the classification of whitefly B. tabaci species (Fig. 1)

Summary

Introduction

Over the last two decades, multiple functions of microbiota have been investigated, from nutrition provision to reproduction (Stouthamer, Breeuwer & Hurst, 1999; Moran, McCutcheon & Nakabachi, 2008; Akman & Douglas, 2009). One particular consequence of genome decay is thought to be the elimination of transcriptional elements within both the coding region and intergenic sequences. In the whitefly Bemisia tabaci species complex, the obligate symbiont Candidatus Portiera aleyrodidarum is of vital importance in nutrient provision, and yet little is known about the regulatory capacities of it. Portiera genomes of two whitefly species in China were sequenced and assembled. Together with two other Portiera genomes from whitefly species available previously, four Portiera genomes were utilized to investigate regulatory capacities of Portiera, focusing on transcriptional elements, including genes related with transcription and functional elements within the intergenic spacers. Comparative analyses of the four Portiera genomes of whitefly B. tabaci indicate that the obligate symbionts Portiera is similar in different species of whiteflies, in terms of general genome features and possible functions in the biosynthesis of essential amino acids. Functional elements are predicted, including 37 Shine-Dalgarno sequences and 34 putative small RNAs

Methods

Results

Conclusion