石斛组培苗遗传差异性ISSR检测

Detecting Genetic Diversity of Dendrobium Tissue Culture Seedlings with ISSR Method

利用简单重复序列间分子标记(ISSR)方法对铁皮石斛、叠鞘石斛、金钗石斛3种石斛种间、同种石斛不同蒴果间、同一石斛蒴果不同植株间及同种石斛不同继代次数组培苗的遗传多样性进行分析.结果表明:(1)3种石斛组培苗种间多态性位点百分率为80.59%,相似系数为0.32,在物种水平上遗传多态性处较高水平.铁皮石斛与金钗石斛的遗传距离最小,为0.406;铁皮石斛与叠鞘石斛的遗传近距离次之,为0.965;金钗石斛与叠鞘石斛的遗传距离最大,为1.099.(2)在同种石斛不同蒴果间,金钗石斛组培苗间遗传差异性最大,多态性位点百分率为77.78%,铁皮石斛次之,为58.82%,叠鞘石斛最低,为28.57%.造成这一现象的原因可能是金钗石斛蒴果数量最多,铁皮石斛次之,叠鞘石斛数量最少.相应地,不同蒴果间的遗传距离分别为0.338、0.301、0.191.(3)同种石斛同一蒴果不同植株间亦存在遗传差异性,金钗石斛不同植株间多态性位点百分率为最大,为25.00%,叠鞘石斛次之,为11.11%,铁皮石斛最小,为7.14%.它们之间的遗传距离分别为0.207、0.047、0.030.(4)3种石斛组培苗在4次继代培养过程中电泳条带带型一致,并未发生质的变化,认为没有发生遗传变异.可见,ISSR分子标记方法可较好地应用于石斛组培苗遗传差异性研究.

In order to investigate the genetic diversity of the tissue culture seedlings of Dendrobium species, molecular marker ISSR was used to detect the interspecific genetic differences among D. officinale, D. denneanum and D. nobile. Genetic diversities of different capsules of the same plant, different plants of the same capsule and different subcultures of the same plant were analyzed. Results showed that： （1） the genetic variance among D. officinale, D. denneanum and D. nobile was at a higher level, with the polymorphism percentage and the similarity coefficient 80.59% and 0.32 respectively. The genetic distance between D. officinale and D. nobile was the smallest （0.406）, and the distance between D. denneanum and D. nobile the largest （1.099）. （2） For the different capsules of the same plant, POPGENE analysis showed that the largest genetic diversity existed within D. nobile （77.78%）, followed by D. officinale （58.82%） and D. denneanum （28.57%）. One possible reason was the larger number of capsules of D. nobile than of D. denneanum. The genetic distances were 0.338, 0.301 and 0.191, respectively. （3） Genetic diversity also existed between different plants of the same capsule. The polymorphism percentage of D. nobile was the largest （25.00%）, followed by D. denneanum （11.11%） and D. officinale （7.14%）. The genetic distances were 0.207, 0.047 and 0.030, respectively. （4） The electrophoresis strips of the 4 subcultures were consistent, with no variation in the process of cultivation. The results, therefore, suggested that ISSR method is suitable for studying the genetic diversity of Dendrobium species. Fig 4, Tab 7, Ref 12