Characterization of a Novel Chitinase from Sweet Potato and Its Fungicidal Effect against .

Black rot, caused by , is a destructive disease of sweet potatoes (). In this study, a novel chitinase () was screened from sweet potatoes, which showed a remarkably higher expression level in resistant varieties than in susceptible ones after inoculation with . Sequence analysis indicated that IbChiA belongs to family 19 class II extracellular chitinase with a MW of 26.3 kDa and pI of 5.96. Recombinant IbChiA, produced by , displayed antifungal activity and stability. IbChiA could restrain the mycelium extension of . FDA/PI double staining combined with transmission electron microscopy observation revealed the remarkable fungicidal effect of IbChiA on the conidia of . The disease symptoms on the surface of slices and tuberous roots of sweet potatoes were significantly reduced after treatment with IbChiA. These results indicated that IbChiA could be used as a potential biofungicide to replace chemical fungicides.