壳斗科植物叶绿体基因组结构及变异分析

Structure and Variation Analysis of Chloroplast Genomes in Fagacea

利用生物信息学方法比较壳斗科6个属14个物种的叶绿体基因组间差异,以近缘物种榛为外类群构建系统进化树,揭示壳斗科叶绿体基因组的结构特征及变异规律。结果显示,14种壳斗科植物的叶绿体基因组均为双链环状分子结构,大小在160 kB左右,差异较小,最大仅差1 366 bp;基因顺序基本一致,而基因数量有所差异,infA、petG、rpl22、ycf1、ycf15等多个基因在部分物种中发生丢失;主要有32个蛋白编码基因长度发生变异,其原因是内含子的丢失、内含子或者编码区的长度改变,华南锥基因长度变异较大; 4个IR边界相对保守,但锥栗、Castanea pumila、华南锥3个物种由于边界扩张导致rps19基因部分序列进入到IR区;以榛为外类群构建的系统发育树,各进化支支持率较高,分辨率较好。研究结果表明,叶绿体基因组可以用于分析关系较近与进化较快物种的系统发生问题,为系统发育和进化研究提供依据。

We compared the differences in chloroplast genomes between 14 species of 6 genera in Fagaceae using bioinformatics methods, and constructed a phylogenetic tree based on the taxonomic group Corylus heterophylla to reveal the structural characteristics and variation patterns of chloroplast genomes in Fagaceae.The chloroplast genomes of 14 Fagaceae plants were double-stranded circular structure with a size of about 160 kB with a small difference, with a maximum difference of only 1 366 bp. The order of the genes was basically the same, but the number of genes was different. infA, petG, rpl22, ycf1, ycf15 and many other genes were lost in some species. There are mainly 32 protein gene length variation, the reason is the loss of introns, introns or length of coding region change, Castanopsis concinna gene length was quite variable. The 4 IR borders were relatively conservative. However, part of the rps19 gene sequence was inserted into the IR region due to the boundary expansion in 3 species of Castanea henryi, Castanea pumila and C.concinna . The phylogenetic tree constructed with C.heterophyllaas a taxon has higher support rate and better resolution.The chloroplast genome can be used to analyze the phylogenetic problems of the closely related and rapidly evolving species, and would provide the basis for phylogenetic and evolutional studies.