珍稀濒危植物石山苏铁的SSR引物设计和遗传多样性分析

SSR Primer Design and Genetic Diversity Analysis of the Rare and Endangered Plant Cycas sexseminifera

关键词:  石山苏铁  SSR分子标记  遗传多样性  遗传结构  保护策略

Key words:  Cycas sexseminifera  SSR molecular marker  genetic diversity  genetic structure  protection strategy

摘要:

揭示珍稀濒危植物石山苏铁(Cycas sexseminifera)种群的遗传多样性水平和遗传分化大小,确定优先保护种群,对石山苏铁的有效保护和管理策略的制定具有重要意义。本研究基于简化基因组序列分析设计Simple Sequence Repeats (SSR)引物,并利用SSR引物进行遗传多样性检测。实验共获得6对SSR引物,6对引物共检测出37个观测等位基因(Na),其中最小观测等位基因数目为3,最大观测等位基因数目为12,平均每个位点等位基因数目为6.167。位点GZST002、GZST055、GZST065、GZST088是高度多态性位点(PIC>0.5)。石山苏铁各种群期望杂合度(He)为0.330-0.533,平均值为0.444,表明石山苏铁遗传多样性处于中等水平;7个种群的He值大小顺序为广西植物研究所引种(ZWS)>崇左广河(GH)>崇左排汝(PR)>隆安陇怀(LH)>崇左中干(ZG)>百色作登(ZD)>隆安新会(XH)。固定系数(F)为-0.161-0.480,平均值为0.074,其中LH、PR、XH 3个野生种群为负值,GH、ZD、ZG 3个野生种群的固定系数则大于0;7个种群的F值大小顺序为百色作登(ZD)>广西植物研究所引种(ZWS)>崇左中干(ZG)>崇左广河(GH)>隆安陇怀(LH)>隆安新会(XH)>崇左排汝(PR)。因此,综合各个遗传指标,石山苏铁需要重点保护和引种的野生种群是遗传多样性相对较高的崇左广河(GH)种群。同时建议开发更多的SSR引物和采集更广范围的石山苏铁野生种群,精准筛选遗传多样性高的优良种群,以利于更全面和准确地评估石山苏铁的遗传多样性水平和濒危机制。

Abstract:

Revealing the level of genetic diversity and genetic differentiation of the rare and endangered plant Cycas sexseminifera population,and determining the priority populations for protection are of great significance for the effective protection and management strategy of C.sexseminifera.In this experiment,Simple Sequence Repeats (SSR) primers were designed based on simplified genome sequence analysis,and SSR primers were used to detect genetic diversity.A total of 6 pairs of SSR primers were obtained in the experiment,and a total of 37 observed alleles (Na) were detected by 6 pairs of primers.The minimum number of observed alleles was 3,the maximum number of observed alleles was 12,and the average number of alleles per locus was 6.167.GZST002,GZST055,GZST065 and GZST088 were highly polymorphic loci (PIC>0.5).The expected heterozygosity (He) of each population of C.sexseminifera was 0.330-0.533,with an average value of 0.444,indicating that the genetic diversity of C.sexseminifera was at a moderate level.The He values of 7 populations were in the order of Guangxi Botanical Research Institute (ZWS)>Chongzuo Guanghe (GH)>Chongzuo Pairu (PR)>Long'an Longhuai (LH)>Chongzuo Zhonggan (ZG)>Baise Zuodeng (ZD)>Long'an Xinhui (XH).The fixation coefficient (F) ranged from -0.161 to 0.480,with an average value of 0.074.Among them,the three wild populations of LH,PR and XH were negative,and the fixed coefficients of the three wild populations of GH,ZD and ZG were greater than 0.The order of F value of 7 populations was Baise Zuodeng (ZD)>Guangxi Botanical Research Institute (ZWS)>Chongzuo Zhonggan (ZG)>Chongzuo Guanghe (GH)>Long'an Longhuai (LH)>Long'an Xinhui (XH)>Chongzuo Pairu (PR).Therefore,based on various genetic indicators,the wild population of C.sexseminifera that needs to be protected and introduced is the Chongzuo Guanghe (GH) population,which has relatively high genetic diversity.At the same time,it is suggested to develop more SSR primers and collect a wider range of wild populations of C.sexseminifera,and accurately screen excellent populations with high genetic diversity,so as to facilitate a more comprehensive and accurate assessment of the genetic diversity level and endangered mechanism of C.sexseminifera.