Comparative Genomics of Facultative Bacterial Symbionts Isolated from European Orius Species Reveals an Ancestral Symbiotic Association.

Xiaorui Chen,Paul D Facey,Ricardo Del Sol,Paul J Dyson,Matthew D Hitchings,Pablo Bielza,José E Mendoza,Virginia Balanza

doi:10.3389/fmicb.2017.01969

Xiaorui Chen, Paul D Facey + Show 6 more

Open Access

https://doi.org/10.3389/fmicb.2017.01969

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Abstract

Pest control in agriculture employs diverse strategies, among which the use of predatory insects has steadily increased. The use of several species within the genus Orius in pest control is widely spread, particularly in Mediterranean Europe. Commercial mass rearing of predatory insects is costly, and research efforts have concentrated on diet manipulation and selective breeding to reduce costs and improve efficacy. The characterisation and contribution of microbial symbionts to Orius sp. fitness, behaviour, and potential impact on human health has been neglected. This paper provides the first genome sequence level description of the predominant culturable facultative bacterial symbionts associated with five Orius species (O. laevigatus, O. niger, O. pallidicornis, O. majusculus, and O. albidipennis) from several geographical locations. Two types of symbionts were broadly classified as members of the genera Serratia and Leucobacter, while a third constitutes a new genus within the Erwiniaceae. These symbionts were found to colonise all the insect specimens tested, which evidenced an ancestral symbiotic association between these bacteria and the genus Orius. Pangenome analyses of the Serratia sp. isolates offered clues linking Type VI secretion system effector–immunity proteins from the Tai4 sub-family to the symbiotic lifestyle.

Highlights

The food needs of an ever-increasing human population must be matched by intensification of crop production, albeit using sustainable approaches to ensure the preservation of ecosystems, biodiversity, and environmental quality
This paper provides the first comparative genomics report on the predominant culturable symbionts associated with several populations of O. laevigatus and other European Orius species, offering a glimpse at facultative microbial populations associated with this important pest control agent
The nutritional benefits of the symbiotic association or the manipulation of host’s reproduction have defined paradigms in the experimental strategies used to explore symbiosis in insects; as demonstrated by the knowledge accumulated in relation to B. aphidicola and Wolbachia sp

Summary

Introduction

The food needs of an ever-increasing human population must be matched by intensification of crop production, albeit using sustainable approaches to ensure the preservation of ecosystems, biodiversity, and environmental quality. Integrated pest management (IPM) strategies have evolved to address the need for a systems approach combining crop protection strategies with the monitoring of agricultural pests and their natural enemies. The use of insect predators as biological control agents has ancient origins, and their use has gathered popularity within the context of IPM programmes as a more environmentally safe and economically viable pest management method. The generalist predator Orius laevigatus in particular is currently used in over 20 countries as a pest control agent (van Lenteren, 2012)

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