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Presentation Time: 2:20-2:40
Home University: North Carolina Central University
Research Mentor: Peggy Cotter, Microbiology & Immunology
Program: M&I-HBCU SROP
Research Title: Burkholderia thaliandensis Contact-Dependent Growth Inhibition Competitions between strains E254 & E264

In nature, microbes use a variety of systems to compete for resources. Burkholderia thaliandensis uses a system called Contact-Dependent Growth Inhibition (CDI) system encoded by the bcpAIOB genes to compete with its neighbors. CDI systems function by delivering a toxin to a recipient cell which then dies unless it is protected by a cognate immunity protein, BcpI. To better understand CDI systems, I studied the CDI systems in two closely related B. thailandensis strains, E264 and E254. E264 has been extensively studied whereas E254 is a new strain to the lab that has a bcpAIOB locus ~97% identical to E264.

We measure the effectiveness of CDI systems through interbacterial competitions where we mark each strain with separate antibiotic resistances and compete them at a 1:1 ratio. Unexpectedly, we discovered that E254 has separate morphologies; both smooth (E254S) and rough (E254R) and that these behave differently in a competition. We also found that E264 lacking the bcpAIOB locus (ΔbcpAIOB) out-competes E254R by a significant margin indicating that the CDI system is not required for competition. Both E264 WT & E264 ΔbcpAIOB compete equally well with E254S. This suggests that either both CDI systems work equally well or that neither is being used. These data indicate that even closely related strains might use CDI systems differently and that further testing is needed.