香蕉种质资源基于rDNA ITS序列的谱系分析

Genealogy Analysis of Banana Germplasm Based on rDNA ITS Sequences

本研究以10份M.acuminata不同亚种材料,6份不同地理来源的M.balbisiana材料及20份不同基因型的香蕉栽培品种为试材,进行r DNA ITS(internal transcribed spacers)序列的测序分析。利用MEGA6.0软件计算不同序列间的碱基组成频率、简约信息位点数,以邻接法进行系统发育分析。结果表明,供试材料的ITS序列长度为583~594 bp,含有169个简约信息位点。基于ITS序列的聚类分析表明,M.acuminata和M.balbisiana的品种间能相互集中分布,形成明显的两支,且具有强的支持率。M.acuminata subsp.errans,M.acuminta var.chinensis和来自斯里兰卡的M.balbisiana具有明显的遗传差异,应加强对上述材料的收集、鉴定和保护,从而为加大香蕉栽培品种的遗传基础,提高香蕉栽培品种的抗逆性提供更多的可能性。

Revealing the phylogenetic relationship among Musa spp. at molecular level would help identify the origin and taxonomy of bananas, and provide theoretical basis for preserving and utilizing wild banana resources.The sequence of ribosomal DNA internal transcribed spacers(ITS) were sequenced from 10 accessions of wild M.acuminata subspecies, 6 accessions of wild M. balbisiana and 20 accesions of banana cultivars with different genotype. The MEGA software(ver. 6.0) was used to analyze the divergences, variable sites and parsim-informative sites. The phylogenetic analysis was conducted by Neighbor-joining(NJ) methods. The results showed that the size of ITS sequences of banana germplasm ranged from 583 bp to 594 bp containing 169 parsim-informative sites.cluster analysis based on ITS sequence showed that M. acuminata complex and varieties of M.balbisiana can formed obviously two clade, and has strong support rate. M. cuminata subsp. errans, M. acuminta var. chinensis and M. balbisiana from Sri Lanka has obvious distant genetic relationships with other accessions. They should be strengthen the collection, identification and protection, to increase the genetic basis of banana cultivars, and provide more possibilities to improve the banana cultivars resistance.