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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分析甜菊属与其近缘种间的亲缘关系，并在系统发育树的基础上检验形态、生态和染色体性状的进化相关性。根据matK序列数据构建的系统发育树表明，石竹科是甜菊属的姊妹群，n=12是甜菊属的祖先染色体数目。10个菊科植物与甜菊属聚为一类，而不是与甜菊属聚为一类，而是与10个属聚为一类，认为甜菊和菊科植物的形态相似是趋同进化的结果。Mcvaugiella(n=13)也被认为是甜菊的近缘种，它不是与甜菊聚在一起，而是与Pachytannus聚在一起(n=17)。这一证据表明，甜菊中n=12和Mcvaugiella n=13是独立起源于n=17的。利用ITS序列数据分析了甜菊属内的系统发育关系。结果表明：(1)一个一年生物种S.aschenborniana(n=12)是所研究的所有其他物种的基础；(2)一个灌木亚种分支(n=12)其次被分枝，(3)多年生物种分成两个分支，系统发育证据表明，染色体数目和世代时间的进化变化是相关的，而染色体数目和基因组大小的进化变化是不相关的；年生和自花授粉的进化变化是相关的，但花大小的减小与年生和自花授粉的变化无关。