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MSc Exit Seminar – Amy Zhang (Guttman/Desveaux Labs)
September 16, 2016 @ 10:10 am - 10:40 am
MSc Exit Seminar
Friday September 16th, 10:10 am – Ramsay Wright Building, Rm. 432
Amy Zhang (Guttman/Desveaux labs)
“Preliminary mapping of HopZ1b resistance-associated loci in Arabidopsis thaliana via EMS and ecotype screens“
Abstract
Pseudomonas syringae is a global plant pathogen that infects agriculturally important crops and the model organism Arabidopsis thaliana. P. syringae deploys type III secreted effectors to suppress immunity and enhance bacterial growth. However, plants possess resistance proteins to recognize these effectors. Thus, effectors have diversified over time to evade recognition. For example, in Arabidopsis Columbia-0, HopZ1a effector triggers robust immunity through ZAR1 resistance protein, but the related HopZ1b elicits a weak resistance-like phenotype.
We conducted EMS and ecotype forward genetic screens to identify induced and natural variations conferring HopZ1b resistance. We found one EMS mutant and one ecotype Gabelstein-0 with enhanced resistance to HopZ1b. Resistance was correlated with bacterial growth inhibition, and enhanced by surface inoculation of bacteria rather than direct injection into plant tissue. Resistance was also dependent on putative effector catalytic function and localization. Preliminary analysis of Gabelstein-0 ZAR1 sequence found an enrichment of variations in the NB-ARC domain. NB-ARC domain acts as a molecular switch for resistance protein activation, and variations in this domain may facilitate activation to the weakly recognized HopZ1b effector.
Ramsay Wright is a wheelchair accessible building.