Is Serratia marcescens strain MCB an entomopathogenic bacterium?: a focus on genomics

Abstract

The phylum nematoda has a variety of functional groups. The parasitic functional group comprise various nematodes some which are parasitic to insects and are known as entomopathogenic nematodes (EPNs). The two most studied genera of EPNs are Steinernema and Heterorhabditis. These EPNs are associated symbiotically with the two enterobacteria genera; Xenorhabdus and Photorhabdus, respectively. The explanation of EPNs has been recently expanded to include the genus Oscheius which have been found to be associated with Serratia species. The bacteria synthesize a range of insecticidal and antimicrobial metabolites which may be useful in various ways as agricultural pest control and medical disease control. An insight into the genome of the nematode-bacterium duo will provide us with information about the symbiosis between the two and parasitism against insect pests. Here in I discuss the isolation and identification of a South African EPN and its symbiotic bacterium. In addition I highlight the production of indole derivatives which are common metabolites produced by entomopathogenic bacteria. The thesis eventually describes and discusses the methods for whole genome sequencing of both the isolated nematode and its symbiotic bacterium, and the genomic content indicate similar genes with other known EPN genera and protein-coding genes involved in symbiosis and parasitism.