四川牡丹和圆裂四川牡丹遗传多样性的ISSR分析

Genetic Diversity of Paeonia decomposita and Paeonia decompositasubsp.rotundiloba Detected by ISSR Markers

利用9条ISSR引物对四川牡丹(Paeonia decomposita)5个居群和圆裂四川牡丹(Paeonia decomposita subsp.rotundiloba)4个居群的遗传多样性进行了初步检测。结果表明:(1)四川牡丹在物种水平上的多态位百分率(PPB)为89.36%,Neis基因多样度(H)为0.291 4,Shannons多样性信息指数(I)为0.441 3;圆裂四川牡丹在物种水平上的多态位百分率(PPB)为81.91%,Neis基因多样度(H)为0.285 7,Shannons多样性信息指数(I)为0.428 5;圆裂四川牡丹的各项多样性参数略低于四川牡丹,而且居群水平上,四川牡丹与圆裂四川牡丹的遗传多样性相对较低。(2)四川牡丹和圆裂四川牡丹居群间遗传分化系数(Gst)分别为0.355 5和0.379 1,2个物种居群内的遗传分化都大于居群间的遗传分化;这2个物种居群间的基因流(Nm)非常有限,其中四川牡丹为0.906 5,圆裂四川牡丹为0.819 0。(3)经Mantel检测,四川牡丹居群间遗传距离与地理距离具有显著正相关关系(r=0.776,P=0.01),而圆裂四川牡丹则不存在显著相关性(r=-0.344,P=0.402)。(4)UPGMA聚类结果显示,四川牡丹与圆裂四川牡丹在分子水平上出现了明显分化,二者为相互独立的物种。研究表明,四川牡丹受到的人为干扰和自然灾害是其濒危的重要原因,与四川牡丹相比,圆裂四川牡丹居群受到的破坏更为严重;建议及时就地保护四川牡丹和圆裂四川牡丹居群的所有个体,而在迁地保护时,因遗传变异主要存在于居群内,应尽可能大量采样,达到最大限度保存其遗传多样性的目的。

The genetic diversity of 5 populations of Paeonia decomposita and 4 populations of Paeonia de- composita subsp, rotundiloba was dectected by inter-simple sequence repeat markers（ISSR）. （1） For P. decomposita, the percentage of polymorphic loci（PPB） at the species level, Nei＇s gene diversity（H） and Shannon＇s information index（1） were 89.36%, 0. 291 4, 0. 441 3, respectively, while for P. decomposita subsp, rotundiloba, the three indices were 81.91%, 0. 285 7, 0. 428 5, respectively, all lower than that of P. decomposita＇s. The genetic variation of them were little lower at population level. （2） The coefficientof genetic differentiation among population（Gst） was 0. 355 5 for P. decomposita and 0. 379 1 for P. de- composita subsp, rotundiloba, suggesting that for both species there is a high genetic differention within population; the gene flow of the two species was 0. 906 5 and 0. 819 0, respectively and show that gene flow was limited among populations. （3） Mantel test indicated that there was a significant correlation be- tween genetic and geographic distances among P. decomposita populations, whereas no significant correla- tion between genetic and geographic distances of P. decomposita subsp, rotundiloba populations. （4） UP- GMA analysis showed significant genetic differention between the two species at molecular level, support- ing the view that they are two separate species. The study indicated that P. decomposita suffered human disturbance and natural disaster may be its endangered reasons. P. decomposita subsp, rotundiloba popu- lations are subjected to severe disruption as well, even more serious than P. decomposita populations. So all the individuals of populations should be protected in situ timely, and it is as large as possible to gain the sample in order to reserve their genetic diversity owning to the genetic variation mainly exist in population.