光皮桦茎叶cDNA文库构建及部分EST序列SSR分析

Library construction of cDNA and SSR analysis of partial ESTs for stem and leaf of Betula luminifera

以光皮桦茎叶组织为材料,构建了cDNA文库。初级文库滴度为1.5×106pfu/mL,重组率达97.3%,插入片段大小在0.5～3.0kb之间,平均长度约为1.3kb,表明所构建的文库质量较高,可用于后续基因克隆及基因表达谱的研究。利用微卫星查找软件对获得的224条EST序列进行微卫星位点搜寻及其丰度、分布比较,发现47条序列含微卫星位点60个,占全部EST序列的26.80%;在所有SSRs中二碱基重复最多,为42个,占总数的70.00%,含三、四碱基重复分别占总数的28.30%和1.70%。通过对光皮桦EST序列中微卫星位点信息的发掘分析,为有针对性地设计EST-SSR引物、进行遗传多样性分析奠定了基础。

A cDNA library of stem and leaf from Betula luminifera was constructed.The primary titer of cDNA library was about 1.5×106 pfu/mL,its recombinant efficiency reached 97.3%,and the size of insert DNA fragments ranged from 0.5 to 3.0 kb,with an average of 1.3 kb.The results indicated that it was a higher-quality cDNA library,and could be used in gene cloning and gene expression profile analysis.Distribution and frequency of SSRs were analyzed in 224 non-redundant ESTs from B.luminifera cDNA library,using online searching software.The results showed that 60 SSRs distributed in 47 EST sequences,accounting for 26.80% of all ESTs.Dinucleotide would be the major repeat types,accounting for 70.00% of the total number of acquired SSRs.The tri-nucleotide and tetra-nucleotide repeats accounted for 28.30% and 1.70% respectively.This research might lay the foundation for designing the targeted EST-SSR primers and genetic diversity analysis by mining the information of EST-SSR loci in B.luminifera EST sequence data.