基于叶绿体DNA变异的湖北梨属种质系统进化及遗传多样性分析

Genetic Diversty and Phylogenetics of Pear( Pyrus L. )Germplasm Resources from Hubei Province Revealed by Chloroplast DNA Variation

利用trnL intron、trnL-trnF、trnS-psbC和accD-psa I等4个叶绿体DNA片段对来自湖北省的88份梨属种质资源进行系统进化和遗传多样性分析。结果表明,4个cpDNA片段共检测到变异位点11个,其中单一突变位点6个,插入/缺失(Indel)位点5个。acc D-psa I多态性最高,其变异位点数、核苷酸多态性和单倍型多样性均为最高。供试梨种质的核苷酸多样性和单倍型多样性分别为0.00112和0.769;Tajima's D检验值在P>0.10水平上均不显著,表明所检测的4个区域以及合并后的片段均遵循中性进化模型;4个序列合并共检测到叶绿体单倍型10个,其中兴山梨种质中检测到的单倍型最多,荆门其次;Hap2和Hap5是2个主要单倍型,分别占总样本数的31.82%和30.68%;中介邻接网络图显示东方梨和西洋梨独立进化,而较为原始的稀有单倍型Hap8和Hap9均位于荆门,暗示该地区可能为砂梨的起源中心或多样性中心之一。

Four non-coding chloroplast region,trn L intron,trn L-trn F,trn S-psb C and acc D-psa I were used to assay genetic diversity and phylogenetics of 88 pear accessions from Hubei province. A total of 11 variation sites included 6 SNP sites and 5 indel sites were recognized. Among 4 cpDNA regions,acc D-psa I exhibited highest polymorphism with the maximum number of variable site,the most abundant haplotype diversity and nucleotide diversity. The values of nucleotide diversity and haplotype diversity of pear accessions identified by four combined cpDNA fragments were 0. 00112 and 0. 769,respectively. All Tajima＇s D values showed no statistical significant differences（ P 0. 10）,which indicated that variation of those chloroplast regions followed natural theory of molecular evolution. A total of ten haplotypes were detected by four cpDNA regions merging analysis. The most haplotypes were derived from the germplasms of Jingmen and Xingshan among 13 collection sites. Hap2 and Hap5 were the two major haplotypes,which accounted for 31. 82% and 30. 68% of the total accessions,respectively. The network analysis of Pyrus L. cpDNA sequences showed that P. communis L. could be completely separated from oriental pear,and the rare haplotype Hap8 and Hap9 were both located in Jingmen,suggesting that Jingmen may be one of the centers oforigin or diversity of Pyrus L..