Submitted to: Mississippi Academy of Sciences Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 11/20/1999
Publication Date: 1/10/2000
Technical Abstract: Understanding the details of molecular interactions between plant pathogens and their host has been greatly assisted by the development of techniques to localize and visualize molecules in planta using lectins, antibodies, and enzymes associated with gold, flourescent, and other labels. The lectin, wheat germ agglutinin, has been sueded successfully in studies on chitin distribution in fungal walls. Wheat germ agglutinin has a binding site for glucosamine molecule of at least two or three residues and requiring an uncharged substituent in the 2-position (which is the structure of chitin). Chitin is a substrate for plant chitinases and is known to elicit host defense responses. 'Chandler' cultivar of strawberry was inoculated with Colletotrichum acutatum and observed for lesion development. Appropriate tissue was fixed, resin embedded, and sectioned for electron microscopy. Chitin was visualized using wheat germ agglutinin conjugated with colloidal gold. The gold probe indicated the distribution of chitin within the mature fungal walls C. acutatum. Several fungi are known to modify or mask chitin in certain penetration structures presumably to avoid detection form the host or to avoid the effects of host chitinases. Studying the distribution of chitin fungal invasion is a necessary part of understanding the intrinsic host-pathogen relationship. We intend to use this technique to determine the distribution of chitin within walls of the invasion structures of C. acutatum.