Kee Sohn
Post Doctoral Scientist
Contact details
+44 (0)1603 450436
Email: kee.sohn@sainsbury-laboratory.ac.uk
Research interests
Plants innate immunity provide defence against microbial attack. The plant innate immune system involves at least two components called PAMP (Pathogen Associated Molecular Patterns)-triggered immunity (PTI) and effector triggered immunity (ETI). The activation of PTI or ETI by direct or indirect recognition of extracellular or intracellular pathogen molecules, respectively, enhances plant disease resistance and restricts pathogen proliferation in plants. However, successful pathogens efficiently suppress plant immunity and cause disease on hosts. One of the primary roles of pathogen effectors is to suppress plant innate immunity.
I am mainly interested in how pathogen effectors suppress PTI or ETI in a model plant Arabidopsis thaliana. Two Pseudomonas effector proteins, AvrRPS4 and AvrB4, suppress PTI or ETI, respectively, in Arabidopsis accessions. AvrRPS4 also triggers RPS4-dependent ETI in resistant Arabidopsis accessions. We found that avirulence and virulence functions of AvrRPS4 in Arabidopsis require distinct sets of properties of AvrRPS4 protein. We also found evidence that molecular requirements for virulence function of AvrRPS4 are conserved in Xanthomonas effector XopO. AvrB4 is a paralogue of AvrB, a well characterized effector protein whose activity on RIN4 is recognized by RPM1, and suppresses race-specific programmed cell death in Arabidopsis. To better understand how pathogen effector molecules interfere with host immune system, we are currently searching for a target protein(s) of AvrB4 in Arabidopsis using yeast two hybrid system.
The downy mildew (Hyaloperonospora parasitica) effector protein ATR13 triggers RPP13-Nd-dependent resistance in Arabidopsis thaliana. To better understand the function of ATR13 during compatible and incompatible interactions of H. parasitica isolates on Arabidopsis ecotypes, we developed a novel delivery system based on the properties of a P. syringae type 3 secretion system (T3SS) effector protein, AvrRPS4. AvrRPS4 is processed to a smaller form in plant cell. We confirmed that AvrRPS4-ATR13-HA protein is delivered and processed in plant cell. ATR13 triggered hypersensitive response (HR) and resistance to bacterial pathogen in Arabidopsis carrying RPP13-Nd when delivered from Pst DC3000. In addition, multiple alleles of ATR13 confer enhanced virulence of pathogen on susceptible Arabidopsis accessions. We are currently investigating the role of ATR13 during pathogenesis in Arabidopsis.
Selected Publications
Sohn, K.H., Zhang, Y. and Jones, JDG (2008) Functions of a Pseudomonas syringae Effector Protein, AvrRPS4, Require in planta Processing and KRVY motif Plant Journal (in press)
An, S.H.*, Sohn, K.H.*, Choi, H.W., Hwang, I.S., Lee, S.C. and Hwang, B.K. (2008) Pepper Pectin Methylesterase Inhibitor Protein CaPMEI1 Is Required for Antifungal Activity, Basal Disease Resistance and Abiotic Stress Tolerance Planta 228, 61-78 *These authors contributed equally to this work
Sohn, K.H., Lei, R., Nemri, A and Jones, JDG (2007) The Downy Mildew Effector Proteins ATR1 and ATR13 Promote Disease Susceptibility in Arabidopsis thaliana. Plant Cell 19, 4077-4090 Featured as Fast Breaking Paper by Thomson Reuters http://sciencewatch.com/sciencewatch/dr/fbp/2009/09febfbp/09febfbpSohnET
Sohn, K.H*., Lee, S.C*., Jung, H.W., Hong, J.K and Hwang, B.K (2006) Expression and Functional Roles of the Pepper Pathogen-Induced Transcription Factor RAV1 in Bacterial Disease Resistance, and Drought and Salt Stress Tolerance. Plant Mol. Biol. 61, 897-915 *These authors contributed equally to this work
Kim, S.H., Hong, J.K., Lee, S.C., Sohn, K.H., Jung, H.W and Hwang, B.K. (2004) CAZFP1, Cys2/His2-type zinc-finger transcription factor gene functions as a pathogen-induced early-defense gene in Capsicum annuum. Plant Mol. Biol. 55, 883-904
Do, H. M., Lee, S.C., Jung, H.W., Sohn, K.H and Hwang, B.K. (2004) Differential expression and in situ localization of a pepper defensin (CADEF1) gene in response to pathogen infection, abiotic elicitors and environmental stresses in Capsicum annuum. Plant Science 166, 1297-1305
