勃氏甜龙竹6个云南地理种群的ISSR多样性分析

Genetic diversity analysis based on ISSR among six populations of Dendrocalamus brandisii in Yunnan Province,China

为了保护云南分布的勃氏甜龙竹种质资源,应用ISSR标记对勃氏甜龙竹6个云南代表性地理种群的遗传多样性和变异进行了研究。从80个引物中筛选出7个用于正式扩增,在调查的6个种群共84个样丛中检测到73个多态位点。研究结果表明:1)云南分布的勃氏甜龙竹遗传多样性较高,在种群水平上,平均多态位点百分率PPB=13.38%,有效等位标记数Ne=1.0906,平均Nei's等位标记多样性指数H=0.0507,平均Shannon信息指数I=0.0742;在物种水平上,PPB=96.05%,Ne=1.5304,H=0.3130,I=0.4714。2)种群间遗传分化水平高,种群间的遗传分化系数(Gst)为0.8427。3)Mantel检测结果显示种群间遗传距离和地理距离之间没有显著的正相关性(r=0.0244,P=0.5740)。推断人类活动的干扰、生境的片段化以及结实率低的生物学特性是导致勃氏甜龙竹种群稀少的主要因素。考虑到云南分布的勃氏甜龙竹遗传多样性和种群间遗传分化水平较高,但种群的个体数量较少,因此应该对勃氏甜龙竹所有种群以及个体实施及时的就地保护,在迁地保护时应在各种群内大量采样。

In order to protect native germplasm resources of Dendrocalamus brandisii in Yunnan Province, China,inter-simple sequence repeat（ISSR） markers were used to assess the genetic diversity and differentiation among 84 clumps from six representative populations of D.brandisii in Yunnan.Seven informative and reliable primers were selected from 80 pre-screened primers and 73 ISSR polymorphic loci were obtained.ISSR markers revealed high genetic diversity among the populations of D.brandisii.At the population level,the percentage of polymorphic loci（PPB） was 13.38% ,the effective number of alleles（Ne） 1.090 6,the average Nei＇s（1972） gene diversity（H） index was 0.050 7 and the average Shannon information index（I） 0.074 2.At the species level,the corresponding values were 96.05%（PPB）,1.5304（Ne）,0.313 0（H） and 0.471 4（I）.A high level of genetic differentiation among populations was detected based on Nei＇s genetic diversity（84.27% ）.There was no correlation between genetic and geographic distance among populations.The effect of human activities,forest fragmentation and low fruiting rates may play prominent roles in the current declining state of D.brandisii.Given this high genetic diversity and differentiation among the populations of D.brandisii in Yunnan,we suggest that all trees from all populations be protected for in situ conservation and enough samples be collected from all populations for ex situ conservation.