Flammulina velutipes is a popular edible basidiomycete mushroom found in East Asia and is commonly known as winter mushroom. Mushroom development showing dramatic morphological changes by different environmental factors is scientifically and commercially interesting. To create a genetic database and isolate genes regulated during mushroom development, cDNA libraries were constructed from three developmental stages of mycelia, primordia and fruiting body in F. velutipes . We generated a total of 15,034 expressed sequence tags (ESTs) from randomly selected clones from the three cDNA libraries. Of these, 6,225 different unique genes (unigenes) were consistent with 4,237 (68%) singlets and 1,998 (32%) contigs. The 6,225 unigenes were compared with the nr database using the BLASTx algorithm. Also, using a homology search in the gene ontology database, the EST unigenes were classified into the three categories of molecular function (20%), biological process (20%), and cellular component (14%). Comparative analysis found great variations in the unigene expression pattern among the three different unigene sets generated from cDNA libraries of mycelia, primordia and fruiting body. The 13~35% of total unigenes were unique to each unigene set and only 4% were shared among all three unigene sets. The unique and common expression in F. velutipes unigenes suggests great differential gene expression profiles during the developmental stages and provides a valuable genetic and biological basis for future study of the basidiomycete mushrooms.
