[Life Sciences Seminar]
            
              
          ▶Subject: Dissecting crosstalk between biotic and abiotic stress tolerance signaling in plants
            
          ▶Speaker: Jiyoung Park, Ph.D. (University of California, San Diego)
                    
          ▶Date: 11:00AM/Sept./23(Wed.)/2015
             
          ▶Place: Life Science Bldg. #207
            
                  *Abctract
               Drought and pathogen infection are two major factors limiting crop yield. Plants in the field are often exposed to more than one stress simultaneously. The plant hormone abscisic acid (ABA) is crucial for resistance to abiotic stresses including drought. Although knowledge of how plants defend against either of these stress forms has advanced, the interplay of the two tolerance mechanisms remains to be elucidated. A recent study using chemical genetics provides evidence for cross-interference, which occurs from biotic stress signaling to antagonize ABA signal transduction. A small molecule, DFPM, rapidly inhibits ABA-dependent gene expression and ABA-induced stomatal closure by activating pathogen effector-triggered immunity (ETI). Further studies revealed DFPM requires early central transducers of ETI, EDS1 and PAD4, and disrupts ABA signaling at the level of Ca2+ signaling. To dissect this interference signaling, Arabidopsis thaliana harboring an ABA-inducible reporter pRAB18:GFP have been EMS mutagenized and screened for altered responses to ABA and DFPM. Four rda (resistant to DFPM inhibition of ABA signaling) mutants were isolated for hyposensitivity to DFPM-mediated inhibition of ABA reporter expression. To map causative mutations, rda mutants were backcrossed into the parental line, and the F2 mapping population was used for whole genome re-sequencing (WGS). WGS results revealed an insertion site of the ABA reporter pRAB18:GFP in chromosome 1. Furthermore, custom-made ShoreMap-based interval mapping identified one region clearly enriched with mutant-specific SNPs. Fine mapping is ongoing to identify the causative mutation for the rda phenotype. Our study shows that chemical genetics screening combined with next generation sequencing-based mapping is identifying novel components involved in cross-talk mechanisms between pathogen resistance signaling and ABA signaling in plants.

                 
         ▶Inquiry: Prof. Youngsook Lee (279-2296) 
     
            * This seminar will be given in English.
        please refrain from taking photos during seminars. *