Abigail Genal Biology
Elizabeth Danka Assistant Professor of Biology
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Abstract
Burkholderia cepacia is a bacterium that can infect plants and immunocompromised humans . Recent work in our lab has focused on the Type 6 Secretion System (T6SS) in B. cepacia. The T6SS functions like a syringe to inject toxins into neighboring bacterial or eukaryotic cells. The genes that encode this complex structure tend to be found in groups called “clusters.” Bioinformatic analysis of the B. cepacia genome found 24 different T6SS gene clusters. We hypothesized that some of these clusters may be important for infection in plants or animals. However, it is unlikely that these clusters are each used in the same environmental conditions. We explored whether T6SS gene cluster expression patterns are affected by temperature, the presence of other bacteria, and components and molecules derived from onions. We isolated the promoters associated with 7 different clusters and determined the promoter activity in different conditions using both qualitative and quantitative assays. Our findings indicate that there is significant variability in when the T6SS gene clusters are used. Some clusters appear to be expressed under all tested conditions, while other promoters are not active under any of the conditions tested or are no longer functional. Future work will characterize the remaining promoters of interest and will identify a specific role for each of the gene clusters. Overall, this project allows us to understand the impact that environmental conditions have on T6SS gene cluster expression and identifies T6SS-mediated mechanisms required for infection in plants and animals.
