伊犁绢蒿SRAP-PCR反应体系的优化及放牧干扰下的遗传多样性

Optimization of SRAP-PCR Reaction System and Study on Genetic Diversities of Seriphidium transiliense under Grazing Condition

为探明放牧干扰下伊犁绢蒿遗传适应机制,在利用正交设计优化伊犁绢蒿SRAP反应体系基础上,采用SRAP分子标记技术对不同放牧强度下伊犁绢蒿种群遗传多样性进行了研究。结果表明:伊犁绢蒿SRAP-PCR的20μl优化反应体系包括1.0mmol/L Mg2+、0.3mmol/L dNTP、0.75UTaq DNA聚合酶、0.45μmol/L引物和30ng模板DNA;19对引物的SRAP扩增共检测出195条清晰条带,其中171条为多态性条带,多态位点百分率为87.69%;伊犁绢蒿种群Nei’s遗传多样性指数、Shannon信息指数放牧后数值降低,随放牧强度增加种群内遗传一致度呈先减少后增加趋势;4个放牧强度上伊犁绢蒿种群总遗传多样度(Ht)为0.2528,种群内遗传多样性(Hs)为0.2201;不同放牧强度种群间基因分化系数(Gst)为0.1040,表明伊犁绢蒿种群大部分(89.60%)遗传变异产生于种群内;种群基因流(Nm)为11.3175,表明种群间有基因交流;以遗传距离构建的UPGMA聚类发现,首先轻牧与重牧聚为一类,然后与中牧聚为一类,随后4个种群聚在一起。

In order to find out the genetic adaptation mechanism of Seriphidium transiliense under grazing disturbance, on the basis of optimization of S. transiliense SRAP PCR system using orthogonal design, genetic diversity of S. transiliense under different grazing conditions was studied by using the technology of SRAP molecular markers. The results showed that optimized 20μ1 SRAP-PCR reaction sys- tem of S. transiliense was 1. 0mmol/L Mg2＋, 0. 3mmol/L dNTP, 0. 75U Taq DNA polymerase, 0.45μmol/L primer and 30ng DNA. 19 pairs of highly polymorphic primers which had good repeatability were selected from 400 pairs of random primers for SRAP amplification,195 clear bands had emerged, of which 171 were polymorphic, accounting for 87.69%. As grazing intensities increased, population Nei＇s genetic diversity index, Shannon information index and genetic identity within populations decreased first and then increased. The total genetic diversity （Ht） among S. transiliense populations under 4 grazing intensities was 0. 2528, genetic diversity within populations （Hs） was 0. 2201, genetic differentiation （Gst） among S. transiliense populations under 4 grazing intensities was 0. 1040, which suggested that 10. 40 percent of the total gene diversity in the S. transiliense＇s population belonged to genetic differences of ma- terials among populations. Majority （89.60%） of genetic variation came from individuals within popula- tions. And gene flow （Nm） was 11. 3715, which suggested that there were gene exchanges among populations. UPGMA cluster constructed by genetic distance demonstrated that light grazing group and over grazing group were clustered into one group first, then middle grazing group were clustered into one group with the new groups, finally the two new groups were clustered together.