Cloning and identification of symbiosis-regulated genes from the ectomycorrhizal Laccaria bicolor

An in vitro conifer ectomycorrhizal model system was developed to study cha nges in gene expression during the establishment of symbiotic relationship. Using the model system and the mRNA differential display technique, we hav e identified cDNA clones from Laccaria bicolor that appear to be involved i n establishing and maintaining the symbiotic relationship between L. bicolo r and red pine. These differentially expressed cDNA clones were obtained fr om mRNA extracted hom the fungus 6-24 h after initiation of interaction. BL AST analysis showed that sequences of these clones did not match with any o f the previously characterized genes. The cDNAs had regions with varying de grees of similarity to genes involved in signal transduction and transcript ional activation.