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Evolution of morphology, ecology and chromosome in the genus Stevia : Molecular phylogenetic approaches

甜菊属形态、生态和染色体的进化：分子系统发育方法

基本信息

批准号：
07454235
负责人：
YAHARA Tetsukazu
金额：
$ 4.99万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

The purpose of this study is to estimate phylogenetic relationships among Stevia and its relatives using molecular data and examine evolutionary correlations of morphological, ecological and chromosomal traits based on the phylogenetic tree.The phylogenetic tree estimated from matK sequence data suggested that Carphocaete is a sister group of Stevia and n=12 is the ancestral chromosome number in the genus Stevia. Ageratum (n=10), which has been regarded as a relative of Stevia, was clustered not with Stevia but with genera with n=10. Morphological similarity between Stevia and Ageratum is considered to be a result of convergent evolution. Mcvaugiella (n=13), which has also been regarded as a relative of Stevia, was clustered not with Stevia but with Pachytamnus with n=17. This evidence suggests than n=12 in Stevia and n=13 in Mcvaugiella are independently derived from n=17.Phylogenetic relationships within the genus Stevia were examined using sequence data of ITS.An obtaiend tree showed that (1) an annual species S.aschenborniana (n=12) is basal to all other species examined, (2) a clade of shurubby species (n=12) is branched next, and then (3) perennial species diverged to two clades, one having n=12 and the other having n=11 and 12.Phylogenetic evidence showed that evolutionary changes in chromosome number and generation time are correlated, but those in chromosome number and genome size are not dorrelated.Evolutionary changes to annuality are correlated with those to self-pollination, but reduction in flower size was not correlated with changes to annuality or self-pollination.

本研究的目的是利用分子数据估计甜菊及其近缘种之间的系统发育关系，并基于系统发育树检查形态、生态和染色体性状的进化相关性。根据matK序列数据估计的系统发育树表明Carphocaete是甜菊的姐妹群，n=12是甜菊属的祖先染色体数。 Ageratum (n=10) 被认为是甜叶菊的近亲，它不与甜叶菊聚集在一起，而是与 n=10 的属聚集在一起。甜菊和Ageratum之间的形态相似性被认为是趋同进化的结果。 Mcvaugiella (n=13) 也被认为是甜叶菊的近亲，它不与甜叶菊聚集在一起，而是与 Pachytamnus 聚集在一起，n=17。该证据表明甜叶菊中的 n=12 和 Mcvaugiella 中的 n=13 独立地源自 n=17。使用 ITS 的序列数据检查了甜叶菊属内的系统发育关系。获得的树显示 (1) 一年生物种 S.aschenborniana (n=12) 是所有其他检查物种的基础，(2) 接下来分支的是灌木属物种 (n=12) 的分支，然后 (3) 多年生物种分化为两个分支，一个具有n=12，另一个具有n=11和12。系统发育证据表明，染色体数量和世代时间的进化变化是相关的，但染色体数量和基因组大小的进化变化不相关。一年生性的进化变化与自花授粉的进化变化相关，但花朵大小的减小与一年生或自花授粉的变化不相关。