Pezicula cinnamomea from cherry tree: pathogenicity tests and photomorphogenesis in culture

Abstract

Pezicula cinnamomea (DC.: Fr.) Sacc. was frequently isolated from dead twigs of flowering cherry (Prunus × yedoensis Matsum.) in Aomori Prefecture, Japan. Inoculations of flowering cherry tree twigs with the fungus resulted in longitudinal browning of heartwood tissues 3–4cm long after 7 months, showing no apparent symptoms on the bark. The fungus were reisolated at high rates from the affected tissues. Apothecia were formed on cut affected twigs when they were placed in a moist Petri dish and kept under near-UV (Black Light Blue; BL-B) light irradiation. On potato sucrose agar (PSA) plates, the fungus failed to form apothecia in the dark, while many apothecia were formed under BL-B and, to a lesser extent, under white light. In nature, the light, especially near-UV, might be an important factor in apothecium formation. Under near-UV from BL-B conidiomata with conidia formed after 5–6 days and mature apothecia after about 14 days. The developmental processes of the apothecium were histologically studied under light and electron microscopes. Pezicula cinnamomea, which is homothallic and fruits easily in culture, may be very useful for life cycle studies and the elucidation of ecological role of this group of fungi.