Submitted to: Mississippi Academy of Sciences Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2001
Publication Date: N/A
Technical Abstract: Anthracnose of strawberry,is caused by Colletrichum fragariae. Penetrations of stolons by C. fragariae is accomplished by a penetrating peg which develops from an appresorium. Inside the host the penetration peg develops into hyphae that infiltrates the host tissue and maintains intimate contact with the host wall. Several plant pathogens mask or modify potential elicitors, such as chitin normally present within fungal walls, perhaps to avoid host defenses, such as chitinase. The distribution of chitin in strategic fungal structures, i.e., conidia, germ tubes, appressoria, penetration pegs, and initial invasive hyphae, can be identified with a lectin probe. Strawberry plants were inoculated with C.fragariae CF-63,incubated, and observed for the development of anthracnose symptoms. At appropriate stages, infected plant material was fixed, embedded, and sectioned for light microscopy. Few or no fungal cells were found in early lesions. Further study with electron microscopy often revealed stressed host cells in the absence of fungal cells. When fungi were observed they were found more often within cortical tissue than epidermal and subepidermal tissues. Preliminary observations indicate that initial invasive hyphae apparently have less chitin than conidia, germ tubes, and older hyphal cells as measured by relative quantity of probe.