The nitrogen fixation symbiosis of legumes and root-nodule bacteria has engendered one of the largest adaptive radiations in the biosphere. At least 13 separate clades of Proteobacteria have evolved to become nodule symbionts for 16,500 legume species in more than 550 genera. My research focuses on basic problems in ecology and evolution of this symbiosis: how new lineages of symbiotic bacteria have originated, how diversity is structured geographically, and why symbiont use varies in different legume clades. Bacterial genes affecting symbiosis are clustered in chromosomal regions ("symbiosis islands"), or on plasmids, that are regularly transferred across lineages. A major focus of research is to understand how such horizontal gene transfer events influence symbiotic coevolution.

recent publications

Parker, M.A. 2012. Legumes select symbiosis island sequence variants in Bradyrhizobium. Molecular Ecology 21: 1769-1778.

Horn K., Parker I.M., Malek W., Rodriguez-Echeverria S., and M.A. Parker. 2014. Disparate origins of Bradyrhizobium symbionts for invasive populations of Cytisus scoparius (Leguminosae) in North America. FEMS Microbiology Ecology 89: 89-98.

Parker, M.A. and A. Rousteau. 2014. Mosaic origins of Bradyrhizobium legume symbionts on the Caribbean island of Guadeloupe. Molecular Phylogenetics and Evolution 77: 110-5.

Reeve, W., Parker, M.A., Tian, R., Goodwin, L., Teshima, H., Tapia, R., Han, C., Han, J., Liolios, K., Huntemann, M., Pati, A., Woyke, T., Mavromatis, K., Markowitz, V., Ivanova, N., Kyrpides, N. 2014. Genome sequence of Microvirga lupini LUT6, a novel Lupinus alphaproteobacterial microsymbiont from Texas. Standards in Genomic Sciences 9: 3.

Parker, M.A. 2015. The spread of Bradyrhizobium lineages across host legume clades: from Abarema to Zygia. Microbial Ecology 69: 630-640.

Parker, M.A. 2015. A single sym plasmid type predominates across diverse chromosomal lineages of Cupriavidus nodule symbionts. Systematic and Applied Microbiology 38: 417-423.

Parker, M.A., Jankowiak, J., Landrigan, G. 2015. Diversifying selection by Desmodiinae legume species on Bradyrhizobium symbionts. FEMS Microbiology Ecology 91:fiv075 (doi:10.1093/femsec/fiv075)

some other publications

Matthew Parker

Biological Sciences

Link to photos from Biol. 472/563 Costa Rica trips:

Costa Rica