A pathogen-induced chitin-binding protein gene from pepper: its isolation and differential expression in pepper...

A chitin-binding protein (CBP) cDNA (CACBP1) was isolated from a cDNA library of pepper (Capsicum annuum L.) leaves infected with Xanthomonas campestris pv. vesicatoria. The deduced amino acid sequence of the CACBP1 gene which has chitin-binding domain and hinge region shares a high level of identity with CBP sequences from tomato, potato and tobacco. The CACBP1 gene was organ-specifically regulated in pepper plants, and differentially induced during the compatible and incompatible interactions of pepper with X. campestris pv. vesicatoria or Phytophthora capsici. Expression of the CACBP1 gene was rapidly induced in the incompatible interactions upon pathogen infection. Transcripts of the CACBP1 gene was highly inducible in the leaves of matured pepper plants by Colletotrichum coccodes infection. In situ hybridization results showed that CACBP1 mRNA was expressed in the phloem area of vascular bundles in C. coccodes-infected leaf tissues. The pathogen-inducible CACBP1 gene was also strongly induced and accumulated in pepper leaves by ethephon, methyl jasmonate or wounding. These data suggest that ethylene and jasmonate may act as signal molecules in the signal transduction pathways of the CBP gene induction during the pepper defense- or pathogenesis-related plant responses.