高山流石滩两种伪装紫堇的表型变异与群体遗传结构

	高山流石滩两种伪装紫堇的表型变异与群体遗传结构
	郭泽敏
导师	牛洋
关键词	伪装植物 Plant camouflage 表型多样性 Phenotypic diversity 多态性 Polymorphism 自然选择 Natural selection 高山冰缘带 Alpine subnival zone
摘要	伪装是生物进化领域中颇受关注的问题之一，它是指生物体隐藏自己、避免自身被观测者（天敌/猎物）识别和发现的一系列策略，而色彩常是伪装成功与否的关键。随着近年来对植物色彩关注的增加，人们逐渐意识到，以伪装为代表的防御手段并不是动物的专利。分布于中国西南山地的两种紫堇属植物——半荷包紫堇（Corydalis hemidicentra）和囊距紫堇（C. benecincta），其叶片具有典型的隐蔽色特征，是研究植物防御色彩进化的理想类群。半荷包紫堇叶片与背景基质表现出较高程度的匹配，在群体间拥有显著的叶色变异，且该表型具有明显的地理特征。囊距紫堇的伪装表型略欠丰富，但不同色型组成使得群体状态更为多样，兼有单态群体（绿色型或伪装型）和二态群体（由绿色型和伪装型组成）。此前已有研究报道了两种紫堇叶片的特殊色彩在绢蝶属昆虫视角下的伪装特征，就地匹配的叶色有助于防御天敌取食和增加生存优势。在此基础上，本研究结合分子地理学和定量色彩研究方法，试图从谱系进化的角度进一步对半荷包紫堇伪装表型多样性的进化动力，以及囊距紫堇群体状态多样性的形成机制进行探讨，以期更加深入地理解植物防御色彩（伪装）进化。我们首先借助分子生物学手段，利用叶绿体基因组数据构建群体间系统发育关系，探讨物种的谱系结构样式及群体遗传分化格局。其次，收集光谱数据，分别从客观量化和加入动物（取食者）色觉模型两方面对物种的表型（叶色）分化格局进行探讨。为深入回答研究类群伪装表型多样性及群体状态多样性的起源问题，我们通过检验表型格局与遗传格局的关系，探讨物种谱系历史是否对不同水平（群体内、群体间）的表型多样性进化具有塑造作用。本研究的主要结果如下：（1）通过全面取样，在研究类群的分布区内各获得半荷包紫堇和囊距紫堇9个群体的分子材料。通过提取叶绿体基因组数据并进行群体遗传结构分析，分别在半荷包紫堇/囊距紫堇中检测到23/12种单倍型，大部分单倍型固定在特定群体中，呈现典型的“天空岛”（sky island）遗传分布格局。系统发育分析显示半荷包紫堇/囊距紫堇形成三/两大谱系分支。两种紫堇在物种及分组水平上均表现出丰富的遗传多样性和遗传分化水平，具有Isolation by distance (IBD) 扩散模式。（2）基于半荷包紫堇8个群体的叶色光谱数据，通过PCA分析和取食者色觉模型定量评估，表明了半荷包紫堇不同群体叶色表型具有显著差异，并在地理分布上表现出一定的连续变异特征。同时，半荷包紫堇大部分伪装群体与原生环境色彩极为匹配，具有就地伪装的适应特征。Mantel test分析显示表型距离与遗传距离不相关，表明表型多样性不是随机产生，而是由自然选择驱动的。（3）基于囊距紫堇6个群体的叶色光谱数据，通过PCA分析和动物色觉模型研究方法，定量评估了不同状态群体的表型变异格局与伪装水平。但由于囊距紫堇表型数据不够完善，且缺乏准确的群体进化时间信息，无法定量群体状态与群体起源时间的关系。囊距紫堇群体多态性问题尚需进一步研究。综上所述，本研究通过对西南山地高山流石滩两种伪装紫堇进行群体遗传格局与表型变异的研究，首次在伪装植物类群中证实了“自然选择过程是驱动伪装表型多样性进化的重要动力”。在此基础上，我们计划今后通过对半荷包紫堇进行全基因组水平的扫描，进一步识别受选择区域和位点，探究相关作用通路以及与伪装表型的关联。同时，未来将全面收集和调查囊距紫堇的表型数据以及群体的色型组成，运用更为可靠的研究方法进一步探讨群体状态多样性的形成机制。; Camouflage is one of the most fascinating topics in evolution. It refers to a series of strategies for organisms to avoid being discovered or identified by observers (natural enemies/prey), and the colour is the key to success. As interest in plant colour has increased recently, there has been a growing realization that camouflage is not exclusive to animals. Distributed in subnival zone of southwest China, Corydalis hemidicentra and C. benecincta are two ideal species for studying the evolution of plant defensive colour due to typical crypsis on leaves. The leaf colour of C. hemidicentra strongly resembles the habitat background of screes, showing significantly phenotypic variation among geographical populations. The camouflage phenotype of C. benecincta is relatively monotonous, but the population state is more diverse due to the composition of different colour morph, involving both monomorphic populations (green or cryptic morph) and dimorphic populations composed of two colour morphs. Previous studies had uncovered the camouflage and background-matching characteristics in situ of leaf colour in two species from the perspective of Parnassius spp., which was conducive to defence against herbivore and enhance survivorship. Here we intend to combine analysis of phylogeny and colour analyses to explore the forces of phenotypic diversity in C. hemidicentra and intrapopulation polymorphism in C. benecincta from the perspective of lineage evolution. Our study is hopeful of providing new insight into the defensive colour (camouflage) evolution in plants. Phylogenetic relationships among populations were constructed using chloroplast genomic data, and phylogenetic and genetic differentiation of populations were first discussed. Secondly, spectra were collected to investigate phenotypic (leaf colour) differentiation patterns based on objective colour analysis and from the vision of animals (herbivores). To further understand the origin of phenotypic diversity and population polymorphism of studied taxa, we examined the association between phenotypic variation and genetic variation, to explore whether the evolutionary history had shaped phenotypic diversity at different levels (interpopulation and intrapopulation). Main results of this study are as follows: (1) The molecular materials from nine populations of C. hemidicentra / C. benecincta were obtained with comprehensive sampling. Using chloroplast genomic data to analyze the genetic population structure, 23/12 haplotypes were detected respectively. Most of the haplotypes were fixed in specific populations, displaying a typical "sky island" genetic distribution pattern. Phylogenetic analysis showed that C. hemidicentra / C. benecincta formed three/two lineages. Both species showed rich genetic diversity and high genetic differentiation at species and grouping level, characterized by isolation by distance (IBD) dispersal pattern. (2) Based on the reflectance spectra of C. hemidicentra from eight popula
语种	中文
	2022-05
学位授予单位	中国科学院大学
文献类型	学位论文
条目标识符	http://ir.kib.ac.cn/handle/151853/75180
专题	昆明植物所硕博研究生毕业学位论文
推荐引用方式 GB/T 7714	郭泽敏. 高山流石滩两种伪装紫堇的表型变异与群体遗传结构[D]. 中国科学院大学,2022.

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