Influence of carbon source on the expression of Cochliobolus carbonum xylan-degrading enzyme genes

The expression of four Cochliobolus carbonum endo-1,4-b-xylanase genes (XYL1, XYL2, XYL3, XYL4), and an exo-1,4-b-xylosidase gene (XYP1) was studied following the growth of the fungus in minimal medium containing glucose, sucrose, xylose, xylan, pectin, or cellulose. The XYL1 and XYL2 genes were expressed only when the culture medium contained xylan or cellulose. Both XYL3 and XYL4 are induced by xylose and xylan, and XYP1 expression is induced by xylose, xylan, pectin and cellulose. None of these genes is expressed in glucose or sucrose media. The differential expression of these enzymes may provide means for the fungus to adapt to different conditions. (African Journal of Biotechnology: 2002 1(2): 64-66