宁夏枸杞与茄科其他植物线粒体基因组的比较与系统进化分析

Comparison and Phylogenetic Analysis of Mitochondrial Genome Among Lycium barbarum and Other Solanaceae Plants

本研究以宁夏枸杞(Lycium barbarum)的主栽品种‘宁杞1号’为参照,分别从基因构成、内含子分布、同源共线性、保守基因簇、重复序列,以及系统进化等方面与目前已报道的辣椒(Capsicum annuum)、茄子(Solanum melongena)、马铃薯(S.tuberosum)、番茄(S.lycopersicum)、天仙子(Hyoscyamus niger)和烟草(Nicotiana tabacum)等六种茄科(Solanaceae)植物的线粒体基因组进行比较分析,以进一步了解它们的线粒体基因组在结构组成上的异同和亲缘关系。结果表明,茄科不同植物的线粒体基因组大小差异较大,从413881 bp(宁夏枸杞)到688698 bp(马铃薯)不等,基因数量在61~71个,其中的蛋白质编码基因除在宁夏枸杞和辣椒中为单拷贝以外,在茄科其他植物中均出现不同程度的多拷贝现象。宁夏枸杞分别与茄子(16个)、马铃薯(16个)和天仙子(15个)共有较多数量的保守基因簇。通过线粒体基因组重复序列分析发现,宁夏枸杞与辣椒的重复序列数量接近,但宁夏枸杞中的简单重复序列(simple sequence repeat)和长度大于1000 bp的散在重复序列(dispersed sequence repeat)在所比较的茄科植物中数量最少。进化分析结果显示,宁夏枸杞与天仙子亲缘关系最近,与烟草的亲缘关系最远。研究结果为进一步揭示茄科植物线粒体基因组在进化过程中的结构变化和功能研究提供参考。

This study used the main cultivated variety of Lycium barbarum‘Ningqi No.1'in Ningxia as the reference to compare the mitochondrial genome(mtDNA)of similarities and differences in structural composition and genetic relationship with that of other six Solanaceae plants reported in present,including Capsicum annuum,Solanum melongena,S.tuberosum,S.lycopersicum,Hyoscyamus niger and Nicotiana tabacum.The aspects of gene composition,intron distribution,homologous collinearity,conserved gene cluster,repeat sequence and phylogenetic evolution were compared.The results showed that the size of mtDNA among different species of Solanaceae plants varied greatly,ranged from 413881 bp(Lycium barbarum)to 688698 bp(Solanum tuberosum),the number of genes was between 61 and 71,the protein-coding genes contained in Lycium barbarum and Capsicum annuum showed single copy,while other Solanaceae plants showed different degrees of multiple copies.Lycium barbarum shared more conserved gene clusters with Solanum melongena(16),S.tuberosum(16)and Hyoscyamus niger(15).In the analysis of mtDNA repeat sequences,Lycium barbarum had similar number of repeat sequences with Capsicum annuum.However,the number of simple sequence repeat and dispersed sequence repeat with length>1000 bp in Lycium barbarum were the least in the Solanaceae plants compared.Phylogenetic analysis showed that Lycium barbarum had the closest genetic relationship with Hyoscyamus niger,and the furthest genetic relationship with Nicotiana tabacum.These results will provide a reference for further revealing the structural changes and functional studies of the mitochondrial genome during the Solanaceae plants evolution.