水曲柳EST-SSRs位点信息分析

EST-SSRs Locus Information Analysis from Fraxinus mandshurica Rupr.

为使EST-SSRs分子标记技术在水曲柳辅助育种、基因定位、雌雄鉴定等研究中应用，本文对NCBI数据库中的12100条水曲柳ESTs进行了分析，序列拼接得到全长为3.02X10。bp的非冗余的5423个ESTs聚类，利用在线软件SSRIT进行SSRs位点搜索，共检索出9489个SSRs位点。EST.SSRs的长度从6—46bp之间变化。二核苷酸重复在水曲柳中占主导地位（6914个），占总SSRs的72.86％，其次是三核苷酸（24.96％）和四核苷酸（1.37％）。各种不同重复模式中出现最多的是（AG／CT）n（3458次），占二核苷酸重复的50.01％，其次分别是（AC／GT）n（24.47％）和（AT／AT）n（24.23％）。利用Primer5.0软件共设计了147对EST.SSRs引物。水曲柳ESTs中SSRs出现频率较高，类型丰富，这一研究结果提供了水曲柳EST.SSRs信息，使该分子标记技术在水曲柳研究中的进一步应用成为可能。

In order to apply the EST-SSRs technique in molecular marker aided breeding, gene localization, and gender identification of Fraxinus mandshurica Rupr. , a total of 12 100 ESTs from NCBI database were analyzed. The sizes of non redundant ESTs added up to 3.02 x 106 bp, which can be clustered into 5 423 clads. A total of 9 489 SSRs loci （6 - 46 bp in length） were found via SSRIT software. Dinucleotide repeats is a predominated feature of these loci （ accounting 72.86% ）, followed by trinucleotide repeats （24.96%） and tetranucleotide repeats （1.37%）. The pattern （AG/CT）n is the most frequent one among all repeat patterns, followed by （AC/GT）n and （AT/AT）n. We designed 147 pairs of EST-SSRs primers by Primer 5.0 software. EST- SSRs in F. mandshurica Rupr displayed a relatively high level of occurrence frequency with abundant patterns. These results will pave the way for application of EST-SSRs molecular marker in F. mandshurica breeding.