Co-Authors:
Porat, R.O.N., Department of Postharvest Science of Fresh Produce, Agricultural Research Organization, Volcani Center, P.O. Box 6, Bet Dagan 50250, Israel, Department of Fruit Tree Breeding and Molecular Biology, Agricultural Research Organization, Volcani Center, P.O. Box 6, Bet Dagan 50250, Israel
Vinokur, V., Department of Postharvest Science of Fresh Produce, Agricultural Research Organization, Volcani Center, P.O. Box 6, Bet Dagan 50250, Israel
Holland, D., Department of Fruit Tree Breeding and Molecular Biology, Agricultural Research Organization, Volcani Center, P.O. Box 6, Bet Dagan 50250, Israel
Gregory McCollum, T., USDA, USHRL, 2001 S. Rock Rd., Ft. Pierce, FL 34945, United States
Droby, S., Department of Postharvest Science of Fresh Produce, Agricultural Research Organization, Volcani Center, P.O. Box 6, Bet Dagan 50250, Israel
Abstract:
Chitinases are well-known antifungal proteins and belong to the pathogenesis-related (PR) group of proteins. In the present study, we screened a Valencia orange flavedo cDNA expression library with an antibody raised against a purified Valencia basic chitinase polypeptide and isolated its corresponding cDNA. The Valencia flavedo chitinase cDNA, designated chi1, is 875bp in length, with an open reading frame of 693bp. The chi1 gene encodes a predicted polypeptide of 231 amino acids with a predicted morecular mass of 25.1 kDa and a pl of 9.15. The CHI1 protein shares 60, 58, and 56% identity with the basic chitinase proteins of rice, grape and maize, respectively. Southern blot analysis indicated that chi1 is present as a low-copy gene. RNA gel blot hybridizations revealed that chi1 gene expression was markedly induced by various treatments that induce fruit resistance against the green mould pathogen Penicillium digitatum (Pers.:Fr.) Sacc. These treatments included elicitation of fruit pathogen resistance by UV irradiation, hot water brushing, and application of β-aminobutyric acid (BABA) and Candida oleophila antagonist yeast cells.