Mian M A Rouf, Saha Malay C, Hopkins Andrew A, Wang Zeng-Yu
Forage Improvement Division, Samuel Roberts Noble Foundation, Ardmore, OK 73401, USA.
Genome. 2005 Aug;48(4):637-47. doi: 10.1139/g05-029.
Microsatellites or simple sequence repeats (SSRs) are highly useful molecular markers for plant improvement. Expressed sequence tag (EST)-SSR markers have a higher rate of transferability across species than genomic SSR markers and are thus well suited for application in cross-species phylogenetic studies. Our objectives were to examine the amplification of tall fescue EST-SSR markers in 12 grass species representing 8 genera of 4 tribes from 2 subfamilies of Poaceae and the applicability of these markers for phylogenetic analysis of grass species. About 43% of the 145 EST-SSR primer pairs produced PCR bands in all 12 grass species and had high levels of polymorphism in all forage grasses studied. Thus, these markers will be useful in a variety of forage grass species, including the ones tested in this study. SSR marker data were useful in grouping genotypes within each species. Lolium temulentum, a potential model species for cool-season forage grasses, showed a close relation with the major Festuca-Lolium species in the study. Tall wheat grass was found to be closely related to hexaploid wheat, thereby confirming the known taxonomic relations between these species. While clustering of closely related species was found, the effectiveness of such data in evaluating distantly related species needs further investigations. The phylogenetic trees based on DNA sequences of selected SSR bands were in agreement with the phylogenetic relations based on length polymorphism of SSRs markers. Tall fescue EST-SSR markers depicted phylogenetic relations among a wide range of cool-season forage grass species and thus are an important resource for researchers working with such grass species.
微卫星或简单序列重复（SSR）是用于植物改良的非常有用的分子标记。表达序列标签（EST）-SSR标记在物种间的可转移性比基因组SSR标记更高，因此非常适合用于跨物种系统发育研究。我们的目标是检测高羊茅EST-SSR标记在代表禾本科2个亚科4个族8个属的12种草种中的扩增情况，以及这些标记在草种系统发育分析中的适用性。145对EST-SSR引物对中约43%在所有12种草种中都产生了PCR条带，并且在所研究的所有饲草中具有高水平的多态性。因此，这些标记将对多种饲草物种有用，包括本研究中测试的那些。SSR标记数据有助于对每个物种内的基因型进行分组。毒麦是冷季饲草的潜在模式物种，在研究中显示出与主要的羊茅属-黑麦草属物种关系密切。发现高冰草与六倍体小麦关系密切，从而证实了这些物种之间已知的分类关系。虽然发现了近缘物种的聚类，但此类数据在评估远缘物种方面的有效性需要进一步研究。基于所选SSR条带DNA序列的系统发育树与基于SSR标记长度多态性的系统发育关系一致。高羊茅EST-SSR标记描绘了广泛的冷季饲草物种之间的系统发育关系，因此对于研究此类草种的研究人员来说是一项重要资源。
