Expression of chitin synthase genes in the arbuscular mycorrhizal fungus Gigaspora margarita

Genomic DNA from spores of the endomycorrhizal fungus Gigaspora margarita w as amplified with two sets of degenerate primers designed on conserved regi ons of chitin synthase polypeptides. Three chitin synthase (chs) gene porti ons were identified: Gimchs1, Gimchs2 and Gimchs3, encoding one class II an d two class IV chitin synthases, respectively. Gimchs1 and Gimchs3 transcri pts were detected by reverse transcription polymerase chain reaction (RT-PC R) during root colonization, whereas none of three mRNAs was revealed durin g spore germination. The potential role of the genes expressed is discussed in the light of morphogenetic and signalling events.