Umbelliferone, a phytoalexin associated with resistance of immature Marsh grapefruit to Penicillium digitatum

• Published in: Phytochemistry (Oxford) Vol. 50; no. 7; pp. 1129 - 1132
• Main Authors: Afek, Uzi, Orenstein, Janeta, Carmeli, Shmuel, Rodov, Victor, Joseph, Moshe Bar
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 01.04.1999; Elsevier
• Subjects: 7-Hydroxycoumarin; Biological and medical sciences; Citrus paradisi; Fundamental and applied biological sciences. Psychology; Fungal plant pathogens; Marsh grapefruit; Pathology, epidemiology, host-fungus relationships. Damages, economic importance; Penicillium digitatum; Phtoalexin; Phytopathology. Animal pests. Plant and forest protection; Resistance; Rutaceae; Umbelliferone; Resistance; Phtoalexin; Marsh grapefruit; Citrus paradisi; Rutaceae; 7-Hydroxycoumarin; Umbelliferone; Penicillium digitatum; Plant pathogen; Botrytis cinerea; Molecular structure; Citrus fruit; Coumarine derivatives; Phycomycetes; Penicillium italicum; Fungi; Phytophthora citrophthora; Disease resistance; Microorganism resistance; Dicotyledones; Angiospermae; Fungi Imperfecti; Thallophyta; Bioassay; Fruit; Host agent relation; Alternaria alternata; Biological activity; Phytoalexin; Microorganism culture; Isolation; Defense mechanism; Spermatophyta
• ISSN: 0031-9422; 1873-3700
• DOI: 10.1016/S0031-9422(98)00671-2

A low concentration (2 mg −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 mg 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 mg g −1 FW, respectively. By that period, the infected area in the yellow fruit was as large as 230 mm 2, as compared with 8 mm 2 in the green fruit. The EC 50 of umbelliferone to P. digitatum growth in vitro was 95 mg 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.