长蕊甜菜树转录组SSR的分布及其序列特征分析

The Distribution and Characteristics Analysis of SSR in Transcriptome of Yunnanopilia longistaminata

本研究对长蕊甜菜树转录组文库中SSR位点的发生频率、平均分布距离、重复基元类型等进行统计分析。在147 990条去冗余的unigene中,有129 734个微卫星位点分布于50 991条序列中,总发生频率为34.46%,平均每1.57 kb就会出现1个SSR位点。在微卫星位点中共有113种重复基元,主要的重复类型是二核苷酸(37.55%)和单核苷酸(26.86%),其中AG/CT和A/T分别是二核苷酸和单核苷酸的优势重复基元,占总SSR位点的43.34%。SSR的重复次数以5~10次为主,占总SSR位点的70.93%,当重复次数为6时,二至六核苷酸数量最多,占总SSR的18.25%。SSR重复序列的长度为10~92 bp,平均长度为19.22 bp,基序长度10~20 bp的占总数的70.53%,在各重复单元中,当序列长度增加时,SSR的出现频率也随之下降。该研究结果为长蕊甜菜树后续的SSR标记开发、种质资源鉴定和遗传多样性分析等奠定了理论基础。

In this study, the frequency of occurrence, average distribution distance, and type of repeat motifs of SSR loci in the transcriptome of Yunnanopilia longistaminata were statistically analyzed. Among 147 990 non-redundant unigene, 129 734 microsatellite loci were distributed in 50 991 sequences, with a total frequency of34.46% and an average of 1 SSR locus per 1.57 kb. There were 113 repeat motifs in microsatellite loci, and the main repeat types were dinucleotide(37.55%) and mononucleotide(26.86%), among which AG/CT and A/T were the dominant repeat motifs for dinucleotide and mononucleotide, respectively, accounting for 43.34% of the total SSR loci. The number of SSR repeats was mainly 5~10, accounting for 70.93% of the total SSR loci. When the number of repeats was 6, the number of dinucleotide to hexanucleotide was the highest, accounting for 18.25% of the total SSR. The length of SSR repeats ranged from 10 to 92 bp, with an average length of 19.22 bp, and the motif length of 10~20 bp accounted for 70.53% of the total. In each repeat unit, the frequency of SSR decreased when the sequence length increased. The results of this study provide a basis for subsequent SSR marker development,germplasm resource identification and genetic diversity analysis of Yunnanopilia longistaminata.