Biology Department Seminar

My research uses computational and experiment approaches to identify genes involved in tolerance to heavy metals such as cadmium, mercury and zinc. Anthropogenic changes to environments can impose immediate stress on native plants, animals and microbes. Adaptation can occur through new mutations or selection on existing alleles or standing genetic variation. The heavy metals cadmium and mercury are highly toxic to most organisms, so how plants and microbes tolerate these metals is of considerable interest. Identifying the genetic basis of tolerance to extreme environments is of central importance for ecologists, evolutionary biologists, molecular biologists and agricultural scientists. To identify the genetic basis of heavy metal transport in plants, an integration of these fields of research is essential. It is also essential for phytoremediation efforts whereby plants and microbes can be used to detoxify contaminated soils. Using an Arabidopsis allopolyploid species, I study the effects of whole genome duplication on heavy metal transporters using gene expression, molecular evolution, genetic diversity and functional genetics in a comparative genomics framework. A second study system that I use is the Medicago-Sinorhizobium mutualism to study the metal transport and detoxification in host plants and symbiotic microbes. A promising approach is to use genome wide association studies (GWAS) and co-expression network analysis to inform us about selection on quantitative traits (including stress related traits), adaptation from standing genetic variation, stabilizing selection, and purifying selection. Medicago truncatula has symbiotic interactions with soil borne nitrogen-fixing bacteria (rhizobia). When plant tissues become too toxic, the host environment (roots) is unsuitable to symbiotic microbes. Therefore, successful symbiosis depends on heavy metal detoxification and large effect alleles that increase metal accumulation would be deleterious. I have identified ma