桑属IIS、trnL-F、rps16序列与进化分析

摘要

[Objective] In this research, the sequences ofMorus-ITS, trnL-F, and rps16 were analyzed to discuss the value of phylogeny. [Method] A total of 67 mulberry genotypes were analyzed (DNA extraction, PCR amplification, sequencing, software splicing, alignment, removing non-sequence bases, downloading Morus ITS, trnL-F, rps16 sequences from GenBank and analyzing percentidentity, calculating length and G+C (A+T) content, mutant sites and informative sites), then these three sequences were combined. A cladogram, generated using MP, was built by using B. papyrifera and C. tricuspidata as outgroup. [Result] The length of basic sequence of mulberry ITS (including 5.8S) is 576 bp, variation range of 576-590 bp, G+C 59.55％-62.25％, 40 informative sites. Mulberry trnL-F intergenic sequence (including the tRNA-Leu intron), the length of basic sequence is 923 bp, variation range of 920-924 bp, A +T 65.87％-66.31％, 23 informative sites. The length of basic sequence ofrps16 intron is 929 bp, variation range of 923-929 bp, A+T 67.28％-67.49％, 17 informative sites. The most possible evolutionary models were (GTR+G), (GTR) and (GTR+G), respectively. And the optimal evolutionary model of the 3-segment-combined analysis was (GTR+G). In the cladogram,Morus nigra is separated first, the rest is divided into two branches. Branch Ⅰ of this cladogram consists of 8 species, including M. wittorum, M. mizuho, M. mongolica, M. mongolica var. diabolica, M. Australis, M. Bombycis, M. Alba and M. atropurprea. Other three members ( M. cathayana, M. Macroura, M. notabilis) falls under branch Ⅱ. [Conclusion] trnL-F and rps16 sequence information sites of Morus is limited, but combined with the ITS sequences, it can improve the branch map information sites, and make branch map more reliable. Based on ITS, trnL-F, rps16 sequence MP, M. nigra (Xinjiang) is divided into a single branch, as the most primitive type, while cultivated species such as Ukraine is the most diverged.%[目的]分析桑属ITS、trnL-F、rps16序列,探讨系统学价值.[方法]67份桑资源,经DNA提取、PCR扩增、测序,测序结果用软件拼接、比对,并从GenBank下载桑属ITS、trnL-F、rps16序列进行同源性分析,计算其长度、G+C(或A+T)含量、变异位点、信息位点,将3个序列合并,以构树、柘树为外类群,采用MP法分析进化关系.[结果]桑ITS(包括5.8S)基本序列长度为576 bp,变异范围为576-590 bp,G+C含量为59.55%--62.25%,40个信息位点;trnL-F(包括tRNA-Leu内含子)基本序列长度为923 bp,变异范围为920-924 bp,A+T含量为65.87%-66.31%,23个信息位点;rps16内含子基本序列长度为929 bp,变异范围为923-929 bp,A+T含量为67.28%-67.49%,17个信息位点.3个序列的最适碱基进化模型分别为(GTR+G)、(GTR)和(GTR+G),可能的分支概率-混合卡方概率值分别为0.000001、0.027175和0.000222,3个片段合并最适碱基进化模型为(GTR+G),基于模型用MP法分析,在2 538个位点中,有80个信息位点.分支图结果表明,首先将黑桑(M.nigra)分出,其它桑种分成2支,第一支包括长穗桑、瑞穗桑、蒙桑、鬼桑、鸡桑、山桑、白桑和广东桑,第二支包括华桑、奶桑和川桑.[结论]桑属traL-F和rps16序列信,息位点有限,单独研究桑属系统学,价值不大,与ITS序列合并研究,则能增加分支图的信息位点,使分支图更近于似然.基于ITS、trnL-F、rps16序列MP分支图,新疆黑桑为最原始类型,乌克兰等栽培种为进化类型.