剪股颖属植物遗传分化及系统关系的分子标记研究

Genetic differentiation and systematic relationships of Agrostis based on multi-molecular marker evidence

剪股颖属植物形态变异大、倍性复杂、种间易于杂交,导致异名多、分类混乱。本研究采用4种分子标记技术,对包括匍茎剪股颖、巨序剪股颖及红顶草在内的7种剪股颖,共58个个体的遗传分化和系统关系进行研究。根据谱带清晰程度及多态性,筛选出9个RAPD引物、2个SSR引物、5个ISSR引物及1个SCAR标记,并建立了最适的PCR反应条件。采用最大简约法和距离法对7种剪股颖植物进行系统树分析,并用靴带检验法计算内部分支的支持率。启发式搜索得到的简约树和由UPGMA方法得到的表征树近乎相同,其中,匍茎剪股颖和红顶草构成单系类群并得到100%的置信支持。红顶草显示了匍茎剪股颖特异性特征谱带,但同时具有不同于匍茎剪股颖的遗传分化,支持将红顶草视为匍茎剪股颖一个变种的观点。对匍茎剪股颖与巨序剪股颖间的遗传分化进行了探讨。

Agrostis is a problematic genus because of difficulties in morphological characterization.These are largely subjected to environmental influences and have resulted in many synonymous species and uncertainties in phylogenetic relationships. Furthermore, Agrostis are normally outcrossing species and exhibit many ploidy levels, resulting in many interspecific hybrids. To study the genetic diversity and relationships between Agrostis, fifty-eight plants representing 7 Agrostis species, including A. stoloni f era, A. alba, and A. gigantea, were investigated using multi-molecular markers. Nine RAPD primers, two SSR primers, five ISSR primers and one SCAR marker were selected and optimal PCR programs were performed. Both maximum parsimony analysis with heuristic search and Unweighted Pair Group Method with Arithmetic Mean （UPGMA） dendrograms clearly distinguished three lineages. One, consisted of four native Agrostis species of Japan, a second included two species （A. stoloni fera and A. alba）, and the third consisted only of A. gigantea. A. stoloni fera and A. alba which formed a monophyletie group and was supported by a 100% strong bootstrap value. A. alba presented several unique A. stolonifera species-special bands so we support the opinion that A. alba is a variety of A. stolonifera. Possible genetic dissimilarities between A. stolonifera and A. gigantea are also discussed.