Abstract
Among the several bacterial secretion systems known to date, Type III secretion system (T3SS) are found in a number of pathogens of animals and plants and constitute needle-like to inject pathogenicity proteins for establishing bacterial niche. Genes for T3SS have been identified in some rhizobial strains and shown to participate in secretion of proteins called Nops however, biochemical functions of the Nops are mostly unknown. Determination of Mesorhizobium loti MAFF303099 genome revealed presence of T3SS gene cluster and posed us questions if and how these T3SS genes have roles in symbiosis. As a first step to elucidate symbiotic roles of T3SS in M. loti, we have conducted, 1) construction of T3SS mutants of MAFF303099, 2) infection tests with a number of host legumes, and 3) construction of over-expression system of T3SS in vitro to obtain Nops.
