白及种质资源及其近缘种的SSR指纹图谱研究

摘要

白及(Bletilla striata Rchb.)为中国珍稀濒危药用植物,野生资源枯竭,混伪种繁多.该研究基于SSR标记技术对16个地区48份白及(Bletilla striataRchb.)样品和4份黄花白及(Bletilla ochracea Schltr.)、4份小白及(Bletilla formosana (Hayata) Schltr.)、4份华白及(Bletilla sinensis (Rolfe) Schltr.)样品进行遗传多样性分析,构建白及种质资源的SSR指纹图谱,并对60份白及样品进行种质资源鉴定,分析白及属种内及其种间的遗传分化特征.结果表明:(1)20对白及SSR引物均能在4个白及属植物中成功扩增,条带清晰且多态性丰富,每对引物的复等位基因数(Na)在4～9之间,等位基因数(Na)总和为127,平均为6.35.(2)筛选出基因型丰富、多态性信息含量(PIC)高的7对白及SSR引物(BJSSR01、BJSSR14、BJSSR15、BJSSR16、BJSSR18、BJSSR19、BJSSR22)构建的白及SSR指纹图谱能将白及属各种质资源清楚分开.(3)白及属在种间水平均有较高的遗传多样性(Na=6.35,I =1.429 1,h=0.706 8),物种间遗传分化强烈(Gst=0.44),物种间的基因流较弱(Nm=0.475 3).(4) UPGMA聚类分析表明,60份供试样品明显聚为4大支,同一物种的个体首先聚在一起,这与形态学分类基本一致;不同来源地的样品种内和种间的亲缘关系有明显差异,地理距离较近的白及样品具有较近的遗传关系.%Bletilla striata Rchb.is an endangered plant with important medicinal values.It has many adulterants,while its wild resources was exhausted.In this study,48 individuals of B.striata sampled from 16 populations,and 4 individuals from its each 3 relatives,including B.ochracea,B.formosana and B.sinensis,were analyzed with SSR markers aiming to reveal their genetic diversity and relationship,to construct their SSR fingerprinting.The results showed that:(1) 20 pairs of primer performed high polymorphism,the alleles ranged from 4 to 9 with summary 127 and average of 6.35 per primer,all of 20 primer were proved amplifiable in 4 species;(2) 7 pairs of primers,BJSSR01,BJSSR14,BJSSR15,BJSSR16,BJSSR18,BJSSR19 and BJSSR22,which performed higher polymorphism,higher polymorphism information content (PIC),were used to build the SSR fingerprints of B.striata and its adulterants.(3)The study revealed that the genetic diversity of B.striata was high (Na =6.35,I=1.429 1,H =0.706 8),genetic differentiation was prominent among species (Gst =0.44),and the gene flow among species was limited (Nm =0.475 3).(4) 4 major groups were generated from 60 accessions tested by UPGMA clustering analyses.Samples from same species were cluster together firstly,which is matched with their morphological taxonomy.Significant differences were revealed not only among the species,but also among the germplasms from different regions.Those with shorter geographic distance performed a tighter genetic relationship.The selection and protection of the excellent varieties of B.striata were also discussed.