Discipline: Biological Sciences
Yvette Singh - California State University Bakersfield
Corky root is a severe disease of lettuce that causes damage to the infected lettuce root. Rhizorhapis suberifaciens is a slow-growing Gram-negative bacterium containing glycosphingolipids in its outer membrane and is the initially isolated corky root-causing bacterium. However, it has been shown that several species as well as bacteria belonging to different genera can cause lettuce corky root. So far the pathogens have only been studied in field settings and from an epidemiological standpoint; little information is known about the genetics of these bacteria and how it causes disease on lettuce. Our lab contains a large collection of corky root-causing bacteria and closely related nonvirulent strains isolated from all over the world. Using polymerase chain reaction (PCR) and sequencing the identity of the bacterial strains was confirmed. A plant seedling assay was optimized using a susceptible as well as a resistant lettuce cultivar. We are currently performing experiments to identify the virulence genes and to test our hypothesis that these virulence genes are located on a conjugative plasmid. This would explain the existence of several closely-related but different genera that are able to cause identical symptoms on lettuce. Also, we are currently creating green fluorescent bacteria that will allow us to track the bacterium during the infection process.
Funder Acknowledgement(s): LSAMP
Faculty Advisor: Isolde Francis, firstname.lastname@example.org
Role: This is a project where I conduct the experiments and collect data.