| Summary: | 碩士 === 國立臺灣大學 === 植物病理與微生物學研究所 === 94 === Lingzhi (Ganoderma lucidum) has been treasured and consumed as a health tonic in easten countries. Ganoderma species belong to the kingdom of Fungi, the division of Basidiomycota, the class of Homobasidiomycetes, the order of Aphyllophorales, the family of Polyporaceae (Ganodermataceae) and the genus of Ganoderma. It is a parasite on many palnts and causes white rot symptoms. Lingzhi has many efficacious components such as polysaccharides, triterpenoids, and adenosine, etc. The main functions of polysaccharides extracted from G. lucidum (PS-G) were confirmed to promote immunity and have antitumor activities. PS-G is a branched-β-glucan, which contains a background chain of (1→3)-linked D-glucose residues, attached mainly with one or two (1→6) D-glucosyl units at O-6 and also with a few short (1→4)-linked D-glucosyl units at O-2 positions. In order to understand the biosynthesis pathway of PS-G, we searched yeast SKN1 gene homolog sequences, which possiblely associated with PG-S synthesis based on the information provided by G. lucidum genome project. In this study, two genes, here here are named Glp4 (Ganoderma lucidum putative β-glucan associated protein 4) and Glp6, were cloned by 5’- and 3’-RACE (rapid amplication of cDNA ends). After sequence analysis and use BLAST to search the amino acid sequences from the database, Glp4 and Glp6 proteins revealed significant similarity with Kre6p and Skn1p from Saccharomyces cerevisiae and Candida albicans. The central region and C terminus are highly conserved among these genes and N terminus has high diversity. In Northern analysis, Glp4 and Glp6 mRNA prepared from fruiting body and hyphae growthing in different carbon source showed different density of band. In order to validate the function of SKN1 gene family of Ganoderma lucidum, we used vectors which contain Glp2 to transform yeast Kre6 mutain strain and taken yeast K1 killer toxin system experiment. The result conform that Glp2 gene and yeast KRE6 gene should has the same function.
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