Identification of four chitin synthase genes in the rice blast disease agent Magnaporthe grisea.

Four chitin synthase gene fragments were isolated from Magnaporthe grisea by use of polymerase chain reaction. A pair of degenerate primers based on conserved zymogen-type chitin synthase sequences amplified a approximately 600-bp product containing three chitin synthase gene fragments. A second pair of degenerate primers, based on conserved sequences between the chitin synthases 3 of Saccharomyces cerevisiae and Candida albicans, amplified a single 770-bp fragment. The four corresponding amino acid sequences each fell into one of the chitin synthase classes I-IV, as deduced from sequence analysis. Northern analysis demonstrated that the class II gene was expressed transiently in early phases of growth, whereas the class I and III genes as well as the class IV gene were expressed throughout the entire life cycle. Furthermore, the class III gene was the most expressed.