Our research in microbiology is focused on the soil bacterium Sinorhizobium meliloti that forms N2-fixing root nodules on leguminous plants. The genome of S. meliloti consists of a typical chromosome (3.6 Mb) and pSymA (1.35 Mb) and pSymB (1.68 Mb) replicons. We study genes and processes involved in the interaction of the bacteria with the plant and more generally process that are important for survival in a soil environment. A major current project is to define and manipulate the minimal genes that are necessary and sufficient for nodule formation and N2-fixation. In a key step to achieving a minimal symbiotic genome, we constructed a S. meliloti strain lacking 45% of its genome. In other work, we are studying genes and uptake systems that are regulated in response to phosphate limitation, and in a separate project a locus that confers resistance to bacterial viruses.

Bioinformatics & Functional Genomics; Microbiology & Plant Biology