Development of primary germ tubes by conidia of Blumeria graminis f.sp. hordei on leaf epidermal cells of Hordeum vulgare

• Published in: Canadian journal of botany Vol. 80; no. 10; pp. 1121 - 1125
• Main Author: Edwards, H H
• Format: Journal Article
• Language: English
• Published: Ottawa, Canada NRC Research Press 01.10.2002
• Subjects: Blumeria graminis hordei; germ tubes; Hordeum vulgare
• ISSN: 0008-4026; 1480-3305
• DOI: 10.1139/b02-092

Development of primary germ tubes from conidia of Blumeria graminis f.sp. hordei on primary leaf segments of Hordeum vulgare was investigated from 3 to 13 h postinoculation (hpi) using transmission electron microscopy. By 3 hpi, the primary germ tube wall that makes contact with the host cuticle develops a small protrusion that breaches the host cuticle and touches the host cell wall but does not penetrate any further. This protrusion is the cuticular peg. From 3 to 13 hpi, the cuticular peg swells, becomes quite electron dense, and finally develops a loose fibrillar texture. The structure of the primary germ tube with the terminal cuticular peg is consistent with the hypothesis that it allows the conidium to absorb water and solutes present in the host cell wall.Key words: powdery mildew, barley, ultrastructure.