【作者】 邓艳芹；

【导师】 黄宏文；

【作者基本信息】 中国科学院研究生院（武汉植物园） ， 植物学， 2007， 硕士

【摘要】 共生或寄生物种成员间的相互作用可以通过循环应答使各成员产生交互的表型变异，受环境的影响还可能形成可塑的表型适应性变异，对物种成员性状表型变异的研究对理解物种间的协同进化及其环境适应性有着重要意义。本研究选取兰科植物-菌根真菌共生关系中的特殊案例——天麻-蜜环菌共生体为研究对象，采取一一对应的采样策略对西部湖北段7个地域不同天麻变型所共生的90株蜜环菌菌丝体6个质量性状和6个数量性状的表型变异进行了观察分析。结果表明：（1）根据6个质量性状的表型变异组合，发现该地区天麻共生蜜环菌菌株群体共有25个形态型，不同天麻变型共生蜜环菌群体间的主体形态型不同，各自特有形态型数目存在差异；（2）蜜环菌群体拥有较高的表型变异多态性(H_mt=3.009；H=0.9712)，各地域群体间表型多样性(H_mt：1.242—2.607；H：0.4736—0.9249)变化幅度大于不同天麻变型共生菌株群体间的变化幅度(H_mt：2.395—2.61；H：0.7723—0.930)，地域群体间的表型分化明显(V_st=0.2356)；（3）差异分析和相关分析结果表明部分蜜环菌表型性状在不同环境因子梯度上存在明显差异或呈显著性的相关；而另一些表型性状变异在不同天麻变型共生菌株群体间存在显著性差异或相关性；（4）聚类分析表明菌株按各形态型聚在一起，但地域群体或天麻变型共生菌株群体的菌株未按各自群体聚类，揭示出菌株表型变异的复杂性。进一步的分析表明，天麻共生蜜环菌菌株群体丰富的表型多样性可能是其长期适应多物种间的相互作用及复杂的生境变换所产生的适应性进化结果，对生境变化有着较强的适应性表型可塑性。相比于经度、纬度和土壤类型等环境因子，海拔梯度对蜜环菌菌株群体的表型性状变异的影响较弱，说明缺乏地理隔离的频繁基因流可能削弱表型生境适应性分化。天麻与蜜环菌间的非对称性相互作用可能是不同天麻变型共生蜜环菌群体间表型性状呈现倾向性的适应性变异的原因，天麻与蜜环菌间可能存在非对称性的协同进化。本研究同时采用ISSR分子标记对西部7个地理位置的与天麻共生的90个蜜环菌菌株进行遗传多样性以及遗传分化分析。6对ISSR引物共检测到169个位点，其中多态位点167个。在物种水平上，Nei的基因多样性指数H和Shannon多样性指数1分别为0.2616和10.4190。7个居群中，五峰居群具有最高水平的遗传多样性。7个地理居群间的遗传分化系数Gst为0.1863，居群间基因流Nm=2.1838。Mantel检验结果表明居群地理距离与遗传距离间无显著相关（r=0.09413，P=0.8292），表明蜜环菌居群的遗传分化符合Wright的地理距离分化模式。湖北西部天麻共生蜜环菌具有较高水平的遗传多样性，且在蜜环菌居群内发生了较大程度遗传分化（81.37％），表明这些天麻共生蜜环菌菌株进行无性克隆繁殖的几率较小。ISSR分子标记研究的三种天麻变型共生蜜环菌群体的遗传分化较小（Gst=0.0299），表明天麻变型对共生蜜环菌的遗传分化影响较小。ISSR分子标记与表型性状变异分析这两种方法检测出蜜环菌基因组的不同部分，结果可以互为补充。更多还原

【Abstract】 Abstract Reciprocal phenotypic change may arise from back-and-force interaction of the species in symbiotic relations or host-parasite pair. Besides, adaptive phenotypic plasticity can occur in fluctuating environment. Therefor, analysis about adaptive phenotypic variance is important for better understanding of flexibility in changeable environment and coevolutionary mechanism between the interactive species. Among many orchid-mycorrhizal fungi pair, Gastrodia elata - Armillaria mellea symbiont was studied in this text for the special relation between them. Using sampling strategy of one A.mellea individual mapping to another G. elata unit, phenotypic diversity of 6 qualitative characters and 6 quantitative characters of 90 A.mellea individuals were observed , which associated with three different G. elata forms in 7 divisions of the Three-Gorge reservoir area in Hubei province. Totally 25 morphological groups of A.mellea were described based on traits of the 6 qualitative characters. A.mellea groups coexisted with different G.elata forms were of distinct main morphology types and peculiar ones. The phenotypic diversity level of the total Armillaria mellea group was high (H_mt=3.009; H=0.9712). Phenotypic diversity level of the populations of the 7 divisions varies by a wider margin(H_mt:1.242-2.607; H: 0.4736-0.9249) than which of the groups coexisted with different G.elata forms(H_mt: 2.395-2.61; H: 0.7723-0.930), and phenotypic differentiation among populations of the 7 divisions was obvious. Variance analysis revealed signifiant phenotypic variance of A.mellea group classified by environment gradients, and there was significantly obvious correlation between phenotypic variance of these groups and environmental factors. Also, there was signifiantly phenotypic variance among the A.mellea group coexisted with different G.elata forms , and significantly obvious correlation between phenotypic variance of the three groups and environmental factors. Clustering analysis showed that A.mellea individuals were not clustered by distinct divisions of the sampling area, nor by G.elata forms in symbiosis . However, the A.mellea individuals of the same morphological types were grouped together. Further analysis results showed that the high phenotypic diversity of A.mellea group associated with G.elata may have resulted both from its long-term interaction with more other species and effects of fluctuating environment, consequently make the A.mellea group have the properties of adaptive phenotypic plasticity in complex and changeable environment. Compared to other environmental factors, such as longtitude, latitude ,and soil type, the effects of altitude gradients on phenotypic variance of A.mellea was weaker, indicating frequent gene flow of less geography isolation may weaken the adaptive phenotypic differentiation. The remarkable tendency of different G. elata forms toward A.mellea groups of different phenotypic variance may arised from the asymmetrical interacting effects of the two species, indicating the existence of asymmetrical coevolutionary relation between G.elata and A.mellea.The genetic polymorphisms and genetic differentiation of the 7 Armillaria mellea populations in Three-Gorge reservoir area, including 90 individuals, were analyzed using inter-simple sequence repeats （ISSR） markers. Totally 169 bands were obtained using 6 ISSR primers, of which 167 bands were polymorphic. At species level, Nei’s diversity index （H） and Shannon’s diversity index（I） were 0.3362 and 0.4976, respectively. The genetic diversity level of WF populaton was higher than other populations. Genetic differentiation coefficient and gene flow value among 7 populations was 0.1863（Gst） and 2.1838, respectively. Mantel test showed weak correlation between genetic and geographic distances among 7 populations（r=0.09413, P=0.8292）, not closing to the ’Isolation-by-distance Model’. In addition to high level of intraspecific diversity, 81.37% genetic differentiation within the populations , indicated that reproduction in Armillaria mellea which coexisted with Gastrodia elata in Three-Gorge reservoir area cannot be exclusively colonal. ISSR markers indicated very little molecular variance among the three Armillaria mellea groups which associated with different kinds of Gastrodia elata forms （Gst=0.0299） , suggesting weak effects of Gastrodia elata forms on Armillaria mellea ’s genetic differentiation .We also compared the results from two methods, i.e. ISSR markers and phenotypic variance analysis , which revealed different parts of genosome of Armillaria mellea and the results they revealed complemented each other.更多还原