裂叶榆叶绿体基因组及CP-SSR位点分析

Chloroplast Genome and CP-SSR Site Analyses of Ulmus laciniata

榆树材质优良,具有良好的耐旱、耐寒和耐盐碱能力,从温带、暖温带到亚热带都有分布。本研究对榆科植物(裂叶榆)的叶绿体基因组进行De novo测序,裂叶榆叶绿体基因组序列全长为158953 bp,为典型的四段式结构,其中LSC区长度为88032 bp,SSC区长18846 bp,两个IR区长26037 bp,GC含量为35. 57%。裂叶榆叶绿体基因组总共编码139个基因,包括85个蛋白编码基因、8个r RNA和46个t RNA基因。裂叶榆的叶绿体基因组存在755个SSR位点,SSR序列长度主要以6~8 bp的短序列为主,SSR共有49个重复单元,以A/T和AT/AT为主,占所有SSR位点的66. 09%。选取42个物种叶绿体基因组的共有蛋白编码基因进行系统进化分析表明,裂叶榆与大麻科、桑科物种亲缘关系最近,榆科与大麻科、桑科均属于荨麻目,与传统分类学相吻合。本研究报道了裂叶榆的叶绿体基因组序列,对今后榆树的光合作用研究、CP-SSR引物开发、进化研究及叶绿体转基因工程等研究具有重要意义。

Elm（ Ulmus）has a long history of using as high-quality hard wood and could grow in temperate, warm temperate ,and subtropical regions for its strong ability to resist biotic stresses（ drought,cold and salt）. By de novo sequencing of the chloroplast genome of Ulmus laciniata Mayr, here we unlocked the chloroplast genome with a length of 158953 bp, which contains four distinct regions, including ：a pair of inverted repeat regions （IR）of 26037 bp, large single-copy region （ LSC ） of 88032 bp, and small single-copy region （SSC） of 18846 bp. The chloroplast genome shows a GC content of 35.57% and contains a total of 139 genes,consisting of 85 protein encoding genes,8 rRNA genes and 46 tRNA genes. A total of 755 SSR loci derived from 49 repeat units were found, and most of them were developed based on 6 to 8 bp short sequence. The large proportion of SSR loci was designed according to A/T and AT/AT（499,66. 09% ）. By phylogenetic analysis using the protein coding sequences of chloroplast genomes in 42 species, U. laciniata was found to be closely related to the plants of Cannabaceae and Moraceae, which belong to the genus Urticales, as revealed in the traditional taxonomy. Thus, this study provided a sequence of chloroplast genome in Ulmus lacirt^ata Mayr, and this resource might be useful in understanding photosynthesis, evolution, primer devel- opment and chloroplast transgenic engineering.