F2023 - CMMB 421 - Virology | ||||||||||
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Research activities have included studies on symbiotic nitrogen fixation, and on development of vector and gene transfer systems for various bacteria of agricultural significance (rumen bacteria, biological control agents, plant-growth promoting bacteria). Our major effort has been directed towards understanding the role of very large plasmids in the free-living and symbiotic life of Rhizobium spp. that form nitrogen fixing nodules on the roots of various legume host plants. Plasmid encoded loci involved in the catabolism of a wide variety of carbon sources have been identified in R. leguminosarum, and the role of these genes in the ability of the bacterium to compete with other bacteria, and to survive as a rhizosphere organism, is being investigated. Horizontal gene transfer between rhizobia, involving both Symbiosis Islands that are self-transmissible and conjugative plasmids, have been a major research focus in the last six years. Studies are also ongoing on partitioning systems that make these plasmids so stable. Another major area of research for the past few years has been the study of chemotaxis and motility in rhizobia, and the regulation of genes involved in these processes. Other lab interests include work on bacteriocins, bacteriophages and IS elements. We have recently developed a project to explore the use of phages to enhance competitiveness for legume inoculants and have been working on genomics and applications of these rhizobiophages for the last several years.
Current Graduate and PhD Students: Deborah Buhlers, PhD student Ribitol catabolism in Rhizobium leguminosarum Kasuni Hemananda, PhD student Regulation of conjugation of rhizobial plasmids Damitha Gunathilake, PhD student Functional genomics of rhizobiophages
Current Postdoctoral Fellow: Maria Augusta Schmidt, PhD Secretion systems for targetting proteins from bacteria to plants.
Recently Completed Graduate Students: Dulmini Wathugala PhD Analysis of conjugation genes in Rhizobium leguminosarum Cynthia Yip, Ph.D. Plasmid replication systems in Rhizobium leguminosarum Anupama Halmillawewa, PhD Characterization of rhizobial phages Hao Ding, PhD Novel conjugation system in Rhizobium leguminosarum |