Co-Authors:
Afek, U., Dept. Postharvest Sci. Fresh Produce, Gilat Experiment Station, ARO, Volcani Center, Mobile Post Negev 2, 85-280, Israel
Orenstein, J., Dept. Postharvest Sci. Fresh Produce, Gilat Experiment Station, ARO, Volcani Center, Mobile Post Negev 2, 85-280, Israel
Carmeli, S., School of Chemistry, Tel Aviv Univ., Ramat Aviv, 69978, Tel Aviv, Israel
Rodov, V., Dept. Postharvest Sci. Fresh Produce, ARO, the Volcani Center, 50 250, Bet Dagan, Israel
Joseph, M.B., Department of Virology, ARO, the Volcani Center, 50 250, Bet Dagan, Israel
Abstract:
A low concentration (2 μg-1 FW) of 7-hydroxycoumarin (umbelliferone) was found in albedo of non-inoculated mature yellow Marsh grapefruit (Citrus paradisi). The concentration of umbelliferone in albedo of immature green grapefruit (2 months before full maturity) was 17 μg g-1 FW. Four days following inoculation with Penicillium digitatum, the accumulation of umbelliferone in the albedo of mature and immature grapefruit was 28 and 250 μg g-1 FW, respectively. By that period, the infected area in the yellow fruit was as large as 230 mm2, as compared with 8 mm2 in the green fruit. The EC50 of umbelliferone to P. digitatum growth in vitro was 95 μg ml-1. Additionally, umbelliferone inhibited growth of several other pathogenic fungi in vitro. It is suggested that umbelliferone plays a role in the defense mechanisms of immature grapefruit against P. digitatum.