CDNA Library Construction And Cloning Of Some Wood Property Genes In Betula Luminifera

A cDNA library was constructed from stem and leaf in Betula luminifera. The primary titer ofthe cDNA library was about1.5ｘ106pfu·mL-1, The recombinant rate was97.3%. The length ofinserted fragments in the vector was between0.5-3.0kb, and the average length was about1.3kb.These data indicate that the cDNA library has a high quality, and can be used in gene cloningand gene expression profile.224high quality ESTs were isolated from270cDNA clones, and therewere160tentative unique transcripts (TUTs) with28.6%redundancy.76ESTs with known orputative function were identified by Blast search against the NCBI non-redundant database. TheseESTs were classified into9different categories,25%of ESTs were involved in metabolism whichlay the foundation for us to study the molecular mechanism of B.luminifera related with characters.Three SuSy genes were isolated from cDNA library, and SuSy1cDNA was2937bp including anORF of2436bp. SuSy2gene was2870bp including an ORF of2424bp. SuSy3gene was2589bpincluding an ORF of2118bp. The expression levels of SuSy genes were detected by qRT-PCR, and theresults indicated that the expression of SuSy1was mainly in root，the expression of SuSy2was mainlyin stem and the expression of SuSy3was mainly in leaves. The results indicated that SuSy2genes mayimportant to the synthesis of xylem while SuSy1and SuSy3may involved in the synthesis of cellulose.Three SAMS genes were isolated from cDNA library, and SAMS1cDNA was1631bp includingan ORF of1011bp. SAMS2cDNA was1608bp including an ORF of1248bp. SAMS3cDNA was1240bp including an ORF of1173bp. The expression levels of SAMS genes were detected byqRT-PCR, and the results indicated that the expression of SAMS1gene were highest in leafs, theSAMS2gene and SAMS3genes were highest in stems. With the deepening of Lignification, theexpression of whole SAMS genes increased firstly and then decreased. The results indicated thatSAMS2and SAMS3genes may related with the synthesis of lignin.