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

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

JOURNAL=Frontiers in Microbiology

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2017.01969

DOI=10.3389/fmicb.2017.01969

ISSN=1664-302X

ABSTRACT=<p>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 <italic>Orius</italic> 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 <italic>Orius</italic> 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 <italic>Orius</italic> species (<italic>O. laevigatus, O. niger, O. pallidicornis, O. majusculus</italic>, and <italic>O. albidipennis</italic>) from several geographical locations. Two types of symbionts were broadly classified as members of the genera <italic>Serratia</italic> and <italic>Leucobacter</italic>, 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 <italic>Orius</italic>. Pangenome analyses of the <italic>Serratia</italic> sp. isolates offered clues linking Type VI secretion system effector–immunity proteins from the Tai4 sub-family to the symbiotic lifestyle.</p>