High-affinity binding site for ethylene-inducing xylanase elicitor on Nicotiana tabacum membranes

Uri Hanania, Adi Avni
1997 The Plant Journal  
Challenge of Nicotiana tabacum cv Xanthi with the ethylene-inducing xylanase (EIX) from Trichodarma viride causes rapid induction of plant defense responses leading to hypersensitive necrosis. This phenomenon is cultivarspecific; no response is detected when N. tabacum cv Hicks is similarly treated. The responsiveness is determined in tobacco and tomato by a single dominant gene. EIX was labeled with fluorescein-isothiocyanate and incubated with cell suspension cultures, protoplasts or
more » ... l membranes. Binding of EIX to the microsomal membranes was found to be specific and saturable, with a dissociation constant of 6.2 nM. Using confocal laser microscopy, the EIX binding site was localized to the plasma membrane. Binding of EIX to its high-affinity site occurred in responsive species. These results demonstrate the existence of a high-affinity binding site for EIX on the plasma membrane of responsive cultivars. Chemical cross-linking of EIX to microsomal membranes from responding plants revealed a 66 kDa protein complex. This protein may function as the receptor that mediates the hypersensitive response induced by EIX binding,
doi:10.1046/j.1365-313x.1997.12010113.x fatcat:em4tbjbmfffpxdf6hkgf6tdaom