The Chalcone Synthase (CHS) Gene Cloning And Bio Informatics Analysis Of Three Species Of Ferns

The fern is a special plant group, is the lowest vascular plants. It is used asmedicine for many years in China; nearly400kinds of ferns can be used as medicine,and has a great effect. The components of ferns are complex; the main biologicallyactive ingredients are flavonoids, phenolic compounds, steroids, alkaloids andtriterpenoids. Among them, flavonoids are of great importance; it have the effect ofdiuresis, removing free radicals, anti-oxidation, inhibition of tumor cells, resistingacetyl cholinesterase etc. Chalcone synthase (CHS) is the first committed enzyme inthe flavonoid biosynthesis. Therefore, the CHS gene cloning and bioinformaticsanalysis from ferns has great significance in finding the flavonoids synthesis pathwayin ferns and the evolution of CHS gene.Based on the above background, we did the following works.1. Using Dryopteris erythrosora as experiment material. The total RNA wasextracted from sporophyte.Then the cDNA sequence of chalcone synthase wascloned by RACE. The full-length of DeCHS gene sequence is1617bp; the open readingframe is1212bp encoding403amino acids; having one intron sequence is563bp;DeCHS gene is a member of chalcone synthase superfamily.2. Clone the cDNA sequence of chalcone synthase from Cyclosorus acuminatusby RACE. The full-length of CaCHS gene sequence is1599bp; the open reading frameis1215bp encoding404amino acids; having one intron sequence is598bp; CaCHSgene is a member of chalcone synthase superfamily.3. Clone the cDNA sequence of chalcone synthase from Salvinia natans by RACE.The full-length of SnCHS gene sequence is1722bp; the open reading frame is1221bpencoding406amino acids; having one intron sequence is514bp; SnCHS gene is amember of chalcone synthase superfamily. 4. Discuss the CHS gene function in the genome sequence structure, the proteinstructure and the gene evolution. We found DeCHS, CaCHS and SnCHS genes havehigh homology with other species of CHS gene. Furthermore, they have the sameessential active sites and similar high-level structure with MsCHS protein. So wesuggested that they have the same function. The study also found that these threeferns introns are TA-GG-introns, which are not similar with other reported specis. wesuspect that this is the unique features in the fern. In addition, building aphylogenetic tree of chalcone synthase genes from77species, we found CHS genehas obvious characteristics of species; the CHS gene of ferns and other plants has acommon origin; ferns have a closer evolutionary relationship with gymnosperms andbryophytes.Flavonoids are important medicinal ingredients of the fern. Chalcone synthase isthe first committed enzyme in the flavonoid biosynthesis. In this study, cloningDeCHS, CaCHS and SnCHS genes has the extremely vital significance at the molecularlevel control flavonoids synthesis，and it also can reveal the origin and evolution ofthe CHS gene.