Oral Technical Session: Mechanism of Host and Non-Host Resistance

102-O

Arabidopsis CRT1 dimerizes with itself and some of its family members through the C-terminal domain carrying a coiled-coil motif.
H. G. KANG (1), R. W. Bullock (1), H. G. Mang (1), Y. Bordiya (1), P. M. Manosalva (2), C. Dharmasiri (3), Z. Fei (2), S. von Einem (4), K. H. Kogel (4), D. F. Klessig (2)
(1) Texas State University, San Marcos, TX, U.S.A.; (2) Boyce Thompson Institute for Plant Research, Ithaca, NY, U.S.A.; (3) Wimberley High School, Wimberley, TX, U.S.A.; (4) Justus Liebig University, Giessen, Germany

Arabidopsis CRT1 (Compromised for Recognition of TCV), an ATPase and endonuclease, is necessary for a wide range of resistance including effector-triggered immunity mediated by resistance (R) proteins and PAMP (pathogen-associated molecular pattern)-triggered immunity (PTI) mediated by PAMP recognition receptors (PRR). Consistent with its role in multiple levels of immunity, CRT1 interacts with 11 R proteins from different structural classes and the FLS2 PRR. Although predominantly localized in endosomes, a subpopulation of CRT1 exists in the nucleus increase in response to pathogen challenges. We found that CRT1 formed a dimer with itself and CRH6, and that CRH6 physically also associated with the HRT R protein. The MultiCoil program predicted that Arabidopsis CRT1 family has a coiled-coil structural motif likely mediating dimerization but not trimerization. Consistent with the prediction, our yeast two hybrid assay with CRT1 truncated variants suggested that the coiled-coil motif residing C-terminal domain of CRT1 is responsible for the intrafamily interaction. Analysis of RNA-seq database indicated that CRT1 is expressed significantly higher than any other CRT1 family members in Arabidopsis. Taken together, these results may suggest that, as either a homo-dmier or a hetero-dimer with CRH6, CRT1 is an important player in the CRT1 family function in Arabidopsis.