2024年2月25日 星期日
台湾含笑变异株群‘中山含笑’的形态特征和遗传变异分析
Analysis on morphological characteristics and genetic variation of Michelia compressa variants Michelia ‘Zhongshanhanxiao’
2022年 第31卷 第3期 页码[44-53]    下载全文[5.7MB]  
摘要

  从台湾含笑〔Michelia compressa (Maxim.) Sarg.〕自然授粉子代中发现18株表型明显变异单株,命名为‘中山含笑’(Michelia ‘Zhongshanhanxiao’)。为明确‘中山含笑’的表型变异及遗传变异状况,弄清其遗传背景和亲缘关系,以‘中山含笑’18株单株、台湾含笑母树及其表型无变异子代单株为样本,在表型特征观察基础上,采用荧光毛细管电泳技术,利用5对SSR引物进行扩增和分析。结果显示:与母树相比,‘中山含笑’的整株、叶片和花的形状均无明显变化,但叶片和花的大小却变化明显;4年生‘中山含笑’的株高、地径、胸径、冠幅、叶长和叶宽分别是同龄表型无变异子代的1.41~1.55、2.49~2.97、2.79~3.16、2.38~2.74、1.40~2.04和1.50~2.17倍,且‘中山含笑’的叶长和叶宽以及花被片的长度和宽度均大于母树,花被片的长度和宽度分别是母树的3.50~4.53和4.33~7.00倍。SSR标记分析结果表明:母树与表型无变异子代的扩增结果完全一致,但与‘中山含笑’18株单株的扩增结果存在明显差异。5个SSR位点中,有4个在母树与表型无变异子代中为纯合位点,而这5个位点在‘中山含笑’大部分单株中为杂合位点。‘中山含笑’供试单株的观测等位基因数、有效等位基因数、观测杂合度、期望杂合度、Shannon’s多样性指数和Nei’s基因多样性指数分别为表型无变异子代的2.50、1.67、3.44、4.06、5.73和4.74倍。母树与表型无变异子代单株的遗传距离均为0.000,表明二者间无遗传差异;‘中山含笑’单株间的遗传距离为0.000~0.539,‘中山含笑’与母树的遗传距离为0.192~0.399,说明‘中山含笑’单株之间、‘中山含笑’与母树之间均存在遗传分化。通过聚类分析,在遗传一致度0.50处,可将供试样本分成2组,其中母树与表型无变异子代单株聚为Ⅰ组,‘中山含笑’18株单株聚为Ⅱ组;在遗传一致度0.64处,‘中山含笑’18株单株还可进一步分为4个亚组。综合分析结果表明:‘中山含笑’供试单株在表型性状上具有明显的超亲特征,且较表型无变异子代具有更高的遗传多样性;除含有台湾含笑母树的遗传信息外,‘中山含笑’供试单株还含有来源于母树之外的遗传信息,据此推测‘中山含笑’为台湾含笑与其他木兰科植物的种间杂交后代。

Abstract

  Eighteen individuals with obvious phenotypic variations were found from progenies of Michelia compressa (Maxim.) Sarg. with natural pollination, and were named as Michelia ‘Zhongshanhanxiao’. To clarify the phenotypic and genetic variations of M. ‘Zhongshanhanxiao’ and figure out its genetic background and relationship, eighteen individuals of M. ‘Zhongshanhanxiao’, mother tree of M. compressa and its progenies without phenotypic variation were selected as samples, and amplification and analysis were carried out with five pairs of SSR primers by using fluorescence capillary electrophoresis technique based on observations of phenotypic characteristics. The results show that there is no significant variation in shape of whole plant, leaf, and flower of M. ‘Zhongshanhanxiao’ compared with the mother tree, but the sizes of leaf and flower vary obviously; the height, ground diameter, diameter at breast height, crown width, leaf length, and leaf width of four-year-old M. ‘Zhongshanhanxiao’ are 1.41-1.55, 2.49-2.97, 2.79-3.16, 2.38-2.74,1.40-2.04 and 1.50-2.17 times of the progenies without phenotypic variation with the same age, the leaf length, leaf width, and the length and width of perianth of M. ‘Zhongshanhanxiao’ are also larger than those of the mother tree, and the length and width of perianth of M. ‘Zhongshanhanxiao’ are 3.50-4.53 and 4.33-7.00 times of the mother tree, respectively.  The result of SSR marker analysis shows that the amplification results of the mother tree are completely consistent with those of the progenies without phenotypic variation, but are obviously different from those of the eighteen individuals of M. ‘Zhongshanhanxiao’. Among the five SSR loci, four loci are homozygous in the mother tree and the progenies without phenotypic variation, while the five loci are mostly heterozygous in the individuals of M. ‘Zhongshanhanxiao’. The number of observed alleles, number of effective alleles, observed heterozygosity, expected heterozygosity, Shannon’s diversity index, and Nei’s gene diversity index of test individuals of M. ‘Zhongshanhanxiao’ are 2.50, 1.67, 3.44, 4.06, 5.73, and 4.74 times of the progenies without phenotypic variation, respectively. The genetic distances between the mother tree and progenies without phenotypic variation are all 0.000, indicating that there is no genetic difference between them; the genetic distances among the individuals of M. ‘Zhongshanhanxiao’ are 0.000-0.539, and those between M. ‘Zhongshanhanxiao’ and the mother tree are 0.192-0.399, indicating that there are genetic differentiations among the individuals of M. ‘Zhongshanhanxiao’, also between M. ‘Zhongshanhanxiao’ and the mother tree. The test samples can be clustered into two groups at the genetic identity of 0.50 by clustering analysis, in which, the mother tree and progenies without phenotypic variation are clustered into group Ⅰ, and the eighteen individuals of M. ‘Zhongshanhanxiao’ are clustered into group Ⅱ; at the genetic identity of 0.64, the eighteen individuals of M. ‘Zhongshanhanxiao’ are further divided into four subgroups. The comprehensive analysis results show that the test individuals of M. ‘Zhongshanhanxiao’ exhibit obvious transgressive traits in phenotypic characteristics, and have higher genetic diversity than the progenies without phenotypic variation. In addition to the genetic information of the mother tree of M. compressa, the test individuals of M. ‘Zhongshanhanxiao’ also contain genetic information absent from the mother tree. It is speculated that M. ‘Zhongshanhanxiao’ is the interspecific hybrids between M. compressa and other species of Magnoliaceae.

关键词台湾含笑; ‘中山含笑’; 表型特征; SSR分子标记; 遗传变异; 遗传关系
Key wordsMichelia compressa (Maxim.) Sarg.; Michelia ‘Zhongshanhanxiao’; phenotypic characteristics; SSR molecular marker; genetic variation; genetic relationship
作者殷云龙, 王芝权, 杨颖, 刘向东, 於朝广
所在单位江苏省中国科学院植物研究所(南京中山植物园), 江苏 南京 210014
点击量930
下载次数815
基金项目江苏省农业科技自主创新资金资助项目〔CX(21)3044〕