Abstract
A multidomain cystatin cDNA (TaMDC1) was isolated from cold acclimated winter wheat. TaMDC1 contains a highly conserved N-terminal cystatin domain (DI) and a C-terminal cystatin-like domain (DII). Northern and western blot analyses showed elevated expression of TaMDC1 mRNA and protein during cold acclimation. Recombinant mTaMDC1 exhibited an inhibitory activity against papain. We found that mTaMDC1 inhibits mycelium growth of the snow mold fungus Microdochium nivale. Hyphae growth was totally inhibited in the presence of 50 μg/ml mTaMDC1 and morphological changes such as swelling, fragmentation and sporulation of the fungus were observed. Domain separation experiments demonstrated that both DI and DII display the antifungal activity, while proteinase inhibitory activity resides within DI. This suggested that proteinase inhibitory activity is not associated with antifungal activity of TaMDC1. The mechanisms of the in vitro antifungal effects and the possible involvement of TaMDC1 in cold induced snow mold resistance of winter wheat are discussed
