38th Annual Meeting of the Society for Invertebrate Pathology

Slugs particularly Deroceras reticulatum are important pests of agricultural and horticultural plants. The bacterium Moraxella osloensis associated with slug-parasitic nematode Phasmarhabditis hermaphrodita has potential for the biocontrol of D. reticulatum. P. hermaphrodita vectors M. osloensis into the shell cavity of D. reticulatum which multiplies and kills slugs. As M. osloensis is the main killing agent, genes expressed by M. osloensis in slugs are likely to play important roles in virulence. In this study, selective capture of transcribed sequences (SCOTS) was employed to identify genes expressed by M. osloensis in D. reticulatum post infection. 11 genes exclusively expressed in the slug by M. osloensis were identified. Most of the identified genes are homologous to other bacteria, and function as cell structure, metabolism et al. Other identified genes do not exhibit similarity to any genes or gene products in current databases, and are thus novel. The products of these genes may be crucial determinants of M. osloensis virulence. Therefore, the identification of genes expressed by M. osloensis in slugs would contribute significantly to the understanding of the virulence mechanism. Characterizing these genes and deciphering their roles should enable us to gain a better understanding of bacterial pathogenesis. Such studies are in progress.