|El rassi, Ziad|
Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/15/2001
Publication Date: 9/27/2001
Citation: Zhang, M., Melouk, H.A., Chenault, K.D., El Rassi, Z. 2001. Determination of cellular carbohydrates in peanut fungal pathogens and baker's yeast by capillary electrophoresis and electrochromatography. Journal of Agricultural and Food Chemistry. 49(11):5265-5269. Available: http://pubs.acs.org/cgi-bin/article.cgi/jafcau/2001/49/i11/pdf/jf0103626.pdf. Interpretive Summary: The peanut plant is attacked by several pathogens that adversely affects its growth and productivity. Two of the most economically important fungal pathogens are Sclerotinia minor (the causal agent of Sclerotinia blight) and Sclerotium rolfsii (the causal agent of Southern blight). Genetic resistance is an attractive alternative to chemical management of these pathogens. Cell walls of many fungi contain chitin and glucan. Chitinase and glucanase enzymes (also called hydrolase enzymes) in plants degrade fungal chitins and glucans. Chitinase and glucanase genes are being introduced in peanut to produce peanut breeding lines with elevated activity of these hydrolase enzymes for possible action against cell walls of fungal pathogens. Therefore, accurate determination of concentration of chitin and glucan in the cell walls of these fungal pathogens will assist in a better interpretation of disease reaction by these fungi on these new peanut plants. In this work, we report on the quantitation of cellular carbohydrates, namely chitin and glucan, in peanut fungal pathogens using advanced chemical analysis methods. Under optimized separation conditions, the contents of cellular carbohydrates including chitin and glucan in Sclerotinia minor and sclerotium rolfsii, were successfully determined. The method described here allowed the assessment of genetic differences in Sclerotium rolfsii isolates from various locations throughout the United States.
Technical Abstract: In this work, the quantitation of cellular carbohydrates, namely chitin and glucan, in peanut fungal pathogens and baker's yeast was carried out by capillary electrophoresis (CE) and capillary electrochromatography (CEC). The chitin and glucan of the fungi were hydrolyzed by the enzymes chitinase and glucanase, respectively, to their corresponding sugar monomers N-acetylglucosamine (GlcNAc) and glucose (Glc). These two monosaccharides were then tagged with 6-aminoquinoline (6-AQ) to allow their separation and detection in CE and CEC. The 6-AQ derivatives of GlcNAc and Glc formed the basis for the determination by CE and CEC of chitin and glucan in peanut fungi and baker's yeast. Several parameters affecting the separation of the 6-AQ derivatives of GlcNAc and Glc including the separation voltage and the composition of the running electrolyte were investigated. Under the optimized separation conditions, the contents of cellular carbohydrate including N-acetylglucosamine, chitin, glucose, and glucan in some fungi, such as Sclerotinia minor, Sclerotium rolfsii, and baker's yeast were successfully determined. The method described here allowed the assessment of genetic differences in Sclerotium rolfsii isolates from various locations.