Phytoparasitica (1996) 24, 163-164

Z. Madar, M. Kimchi, Z. Solel, J. Riov and A. Sztejnberg (1996)
Phytoalexin production by cypress in response to infection by Diplodia pinea f.sp. cupressi
Phytoparasitica 24 (2), 163-164
The 17th Congress of the Israeli Phytopathological Society, February 19-20, 1996 (Bet Dagan, Israel), lecture
Abstract: The antifungal terpenoid compounds cupressotropolone A (6-isopropyl-tropolone ß- glucoside) and B [5-(3-hydroxy-3-methyl-trans-1-butenyl)-6-isopropyl-tropolone ß-glucoside] were isolated for the first time from the bark of Italian cypress, after inoculation with the fungus Diplodia pinea f.sp. cupressi. The terpenoid compounds inhibited in vitro spore germination of D. pinea f.sp. cupressi, Seiridium cardinale, Alternaria alternata and Verticillium dahliae. Production of the antifungal terpenoid compounds was also induced by S. cardinale, causing cankers on Italian cypress. The antifungal terpenoid compounds were fungistatic. Predisposition of cypress saplings to extreme water stress enhanced the development of cankers caused by D. pinea f.sp. cupressi and enhanced fungal colonization in the bark and xylem in comparison with normally watered plants. Production of both cupressotropolone A and B in the bark, which commenced soon after the inoculation, was lower in plants predisposed to water stress. In plants treated with (aminooxy)acetic acid, a metabolic inhibitor, the cankers were significantly longer and the content of phytoalexins was significantly lower than in untreated plants. An extract of the bark of initiated cankers with 15% aqueous methanol, enhanced the subsequent development of the cankers, and reduced the content of both phytoalexins in the bark significantly in comparison with untreated plants. These results suggest that the terpenoid phytoalexins greatly inhibited canker development.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)

Research topic(s) for pests/diseases/weeds:
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Diplodia sapinea	Cypress (Cupressus)	Israel