Tesia Posekany
Tesia Posekany
Faculty Advisor: Greg Martin
Year: 2013

Development of reporter genes for monitoring effector-triggered immunity in tomato

Plants rely on two innate immune systems to combat pathogens: pattern-triggered immunity (PTI) and effector-triggered immunity (ETI). Pathogen-associated molecular patterns (PAMPs) responsible for the elicitation of PTI, are highly conserved, and detection of PAMPs forms the frontline of defense for the plant cell. Effector proteins delivered by the pathogen into the plant cell suppress PTI, enabling pathogen success; however, some plants possess resistance (R) genes conferring recognition of effectors leading to ETI.

Pto, an R gene natively present in tomato, recognizes AvrPto and AvrPtoB bacterial effectors fromPseudomonas syringae pv. tomato (Pst), and Pto-AvrPto/AvrPtoB is used as a model system for studying ETI. This project aimed to develop reporter genes for ETI in tomato for use as identifiers of this robust immune response in research applications. Based on previous RNA-seq data from tomato plants collected six hours post-infiltration with different DC3000 strains (a model Pst strain) mutated to elicit solely PTI or ETI, four candidate genes were selected as possible reporter genes for ETI. Real-time quantitative PCR technology confirmed statistically significant up-regulation of three of the genes selected solely during ETI at six hours post-infiltration. An inoculation time course was started to test the usefulness of the reporter genes at different stages of infection. Preliminary time course data suggests a consistent up-regulation of one candidate gene up to 12 hours post-infiltration and therefore it appears to be a robust reporter gene for Pto-mediated ETI in tomato. Future work will test its broader utility for ETI associated with other R genes.

My Experience

My research experience at the Boyce Thompson Institute for Plant Research was pivotal in my decision to attend graduate school. My research project entailed working side-by-side with scientific leaders and experts in the plant pathology field, thereby gaining an accurate perception of the life scientific researchers lead. I gained valuable additions to my molecular biology skillset including real-time quantitative PCR, cloning, primer design, RNA isolation, and cDNA synthesis. Additionally, I gained invaluable insight into my desire to become a Ph.D. scholar. I truly believe that my experience at BTI allowed me to become a serious Ph.D. applicant and provided me with personal insight that I would not have discovered otherwise.