Transcriptomic responses of the olive fruit fly Bactrocera oleae and its symbiont Candidatus Erwinia dacicola to olive feeding

Nena Pavlidi,Boaz Yuval,Anastasia Kampouraki,Edouard Jurkevich,Thomas Van Leeuwen,John Vontas,Michael Ben-Yosef,Anastasia Gioti,Nicky Wybouw,Wannes Dermauw

doi:10.1038/srep42633

Abstract

The olive fruit fly, Bactrocera oleae, is the most destructive pest of olive orchards worldwide. The monophagous larva has the unique capability of feeding on olive mesocarp, coping with high levels of phenolic compounds and utilizing non-hydrolyzed proteins present, particularly in the unripe, green olives. On the molecular level, the interaction between B. oleae and olives has not been investigated as yet. Nevertheless, it has been associated with the gut obligate symbiotic bacterium Candidatus Erwinia dacicola. Here, we used a B.oleae microarray to analyze the gene expression of larvae during their development in artificial diet, unripe (green) and ripe (black) olives. The expression profiles of Ca. E. dacicola were analyzed in parallel, using the Illumina platform. Several genes were found overexpressed in the olive fly larvae when feeding in green olives. Among these, a number of genes encoding detoxification and digestive enzymes, indicating a potential association with the ability of B. oleae to cope with green olives. In addition, a number of biological processes seem to be activated in Ca. E. dacicola during the development of larvae in olives, with the most notable being the activation of amino-acid metabolism.

Highlights

Compound in the olive fruit, representing the major constituent of unripe, green olives[7,8]
The transcriptome of B. oleae has been sequenced by 454 pyrosequencing[10], and transcriptomics have been employed for the investigation of different aspects of B. oleae biology such as spinosad resistance[11], the differences between female and male reproductive systems and differential expression of olfactory genes[12]
It has been proposed that the symbiotic bacteria may provide the olive fruit fly with some advantage related to survival within the harsh environment of unripe olives, either by detoxifying phenolic compounds or by being involved in the enzymatic hydrolysis of dietary proteins and the synthesis of amino acids directly related to nutrient availability, which is limited in green olives[13,17,18]

Summary

Introduction

Compound in the olive fruit, representing the major constituent of unripe, green olives[7,8]. It has been proposed that the symbiotic bacteria may provide the olive fruit fly with some advantage related to survival within the harsh environment of unripe olives, either by detoxifying phenolic compounds (e.g. oleuropein) or by being involved in the enzymatic hydrolysis of dietary proteins and the synthesis of amino acids directly related to nutrient availability, which is limited in green olives[13,17,18] Evidence for this hypothesis comes from two recent studies, indicating a role for the gut bacterial community in overcoming host defense and in nitrogen source utilization[13,19]. E. dacicola genes during larval development in green and black olives

Methods

Results

Conclusion