The Difference Of CAZymes Between Tremella Fuciformis And Hypoxylon Sp

Tremella fuciformis Berk, is a well-known edible fungus in China, commonly referred to as the snow fungus, and used as a human medicine to decrease cholesterol. On sawdust, growth and reproduction of T. fuciformis is only possible with the presence of other fungi such as Annulohypoxylon stygium, commonly called Xianghui. Commercial cultivation of T. fuciformis is not possible without companion fungi such as A. Stygium. According to (somebody) investigation, T.fuciformis mycelium lack enzymes to rot wood, whereas A. Stygium mycelium are powerful in degradating lignocelluloses. In this study, the whole geome sequences of T. fuciformis T0040 and A. Stygium G03 were used to analyze the quantity variance in carbohydrate related genes between thses two symbiotic fungi. This analysis aim to seek more evidences to identify the relationship of these fungi in the view of enzymology.(1) In this experiment, we sequencing the strains tremella fuciformis T14 and hypoxylon sp G03, and assemble them. The result of assembling showed that the total length of the assembled genome of Hypoxylon sp was about 37.2Mb that included 47.02% GC content 571 and scaffolds in which N50 was 323,327bp and N90 was 66,321. At the same time, we gained about 24Mb assembled genome of Tremella fuciformis which included 1873 scaffolds and more than 55% GC content. With the forecast of software Augustus (version2.5.5) specially using for fungus, we gained 8599 genes from the whole genome of Hypoxylon sp and 9618 genes from tremella fuciformis. Then we annotated the function of these genes using NR、Swissprot、 KEGG and CAZy data base,et al.(2) The result of Carbohydrate-Active Enzyme database(CAZy) annotation from Tremella fuciformis and Hypoxylon sp showed that the total number of annotated CAZymes genes were 260 in Tremella fuciformis genome, which is lower than the average (333) of the ten fungus in this study, and its genome matrix-degrading enzymes (cellulose、hemicellulase、pectinase and amylase)genes also lower than the ten studied fungus(41/85), just higher than Saccharomyces cerevisiae and Tremella mesenterica. The genome of Tremella fuciformis contains richer amylase and β-glucosidase genes (one of the three cellulase) compared with other matrix-degrading enzymes,13 and 15 genes, respectively. The CAZy data base identified total 367genes, containing 124 matrix-degrading enzymes genes which is higher than the average of ten studied fungus encoded in the genome of hypoxylon sp. In the ten studied fungus, hypoxylon sp’s matrix-degrading enzymes genes just lower than Stereum hirsutum(142) and Aspergillus nidulans(136). From this study, we can find that the cellulose of hypoxylon sp (49) is the highest in the analysis of fungi, the cellulose genes mainly distributed in endo-1,4-β-D-glucanase and β-1,4- glucosidase. From the result of this study, we can draw a conclusion for matrix-degrading enzymes gene, there is complementary relationship between tremella fuciformis and hypoxylon sp at genetic level.(3) From the analysis of enzymological experiment results, it revealed that pure tremella fuciformis has almost no activity in cellulase、xylanase and laccase, while single hypoxylon sp possesses a very high activity of beta-glucosidase and xylanase, and also a higher endonuclease (endo-1,4-β-D-glucanase) activity, but there is not any exo-1,4-(3-D-glucannase activity measured in single hypoxylon sp; When tremella fuciformis and hypoxylon sp were cultivated together in edible fungi bag, it showed that the enzyme activity within the primordium (hyphae that both tremella fuciformis and hypoxylon) is generally higher than the hypoxylon sp cuotivated alone.And the laccase is only active in certain time, almost not in the later cultivation. The experiments demonstrated that it has strong complementarity of the enzyme activity between tremella fuciformis and hypoxylon sp, and there is a synergistic effect within the two enzyme activities.