九寨沟县麦吊云杉(Picea brachytyla)群体遗传多样性

Population Genetic Diversity of Picea brachytyla in Jiuzhaigou County

研究麦吊云杉天然群体遗传多样性,为其种质资源遗传保育、资源利用提供参考依据。本研究以九寨沟地区的麦吊云杉天然群体为研究对象,根据其自然分布状况选择6个不同区域采集到90个样本,利用简化基因组测序(GBS)技术进行遗传多样性分析。结果显示,6个麦吊云杉天然群体可划分为高、中、低海拔3个亚群。群组1(POP1)主要为太平沟(TPG)和甲勿池(JWC)群体,属于低海拔亚群;群组2(POP2)主要为七寨沟(QZG)和亚隆沟(YLG)群体,属于中等海拔亚群;群组3(POP3)主要为神仙池(SXC)和贡岗岭(GGL)群体,属于高海拔亚群。SXC群体处于POP2和POP3亚群之间,与这两个亚群的遗传交流相对较为广泛。6个群体间的遗传分化系数均较低,表现出低水平的遗传分化。6个群体的多态信息(PIC)值均在0.900以上,说明6个群体均具有高的多态性。观测杂合度与期望杂合度的变化范围分别在0.232~0.244和0.190~0.199之间,各群体间无明显差异,表明麦吊云杉天然群体具有较低的遗传多样性水平。相关分析结果显示,九寨沟麦吊云杉天然群体的遗传多样性与海拔、纬度呈负相关,与经度相关性不明显。遗传多样性自JWC向GGL沿海拔梯度的升高而降低。本研究结果为麦吊云杉遗传保育提供依据,在进行种质资源保存时应尽量选择较低海拔的资源。

To study the genetic diversity and sampling strategy of natural Picea brachytyla populations and provide references for protecting their genetic diversity and resource utilization.In this study,the genetic diversity of six natural P.brachytyla population(90 individuals) were analyzed by genotyping-by-sequencing(GBS).The re sults showed that six populations could divided into three subsets with high,medium,and low elevation.POP1 belonged to low elevation subset,and mainly obtained individuals in TPG and JWC.POP2 belonged to medium elevation subset,which mainly obtained individuals in QZG and YLG.POP3 belonged to high elevation subset,and mainly obtained individuals in SXC and GGL.SXC was between subset POP2 and POP3,which had genetic communication with the two subsets.There were low genetic differentiation coefficient among six populations,showed a low level of genetic differentiation.The PIC value were all higher than 0.900,indicated that there were highly polymorphism in six populations.The observe heterozygosity and expect heterozygosity were 0.232~0.244 and0.190~0.199,respectively,and there were no difference between populations,indicated that there remained low level of genetic diversity in P.brachytyla natural populations.The results of correlation analysis showed that there were negative correlation between genetic diversity and altitude,and latitude,and there were no correlation between genetic diversity and longitude.The genetic diversity were decreased with the increase of altitude(From JWC to GGL).This study would provide basis for P.brachytyla genetic conservation.The collection of resources in low altitude would be necessary in germplasm conservation of P.brachytyla.