Raggi Lorenzo, Bitocchi Elena, Russi Luigi, Marconi Gianpiero, Sharbel Timothy F, Veronesi Fabio, Albertini Emidio
Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, Perugia, Italy.
Dipartimento di Scienze Agrarie, Alimentari ed Ambientali, Università Politecnica delle Marche, Ancona, Italy.
PLoS One. 2015 Apr 20;10(4):e0124709. doi: 10.1371/journal.pone.0124709. eCollection 2015.
Poa pratensis L. is a forage and turf grass species well adapted to a wide range of mesic to moist habitats. Due to its genome complexity little is known regarding evolution, genome composition and intraspecific phylogenetic relationships of this species. In the present study we investigated the morphological and genetic diversity of 33 P. pratensis accessions from 23 different countries using both nuclear and chloroplast molecular markers as well as flow cytometry of somatic tissues. This with the aim of shedding light on the genetic diversity and phylogenetic relationships of the collection that includes both cultivated and wild materials. Morphological characterization showed that the most relevant traits able to distinguish cultivated from wild forms were spring growth habit and leaf colour. The genome size analysis revealed high variability both within and between accessions in both wild and cultivated materials. The sequence analysis of the trnL-F chloroplast region revealed a low polymorphism level that could be the result of the complex mode of reproduction of this species. In addition, a strong reduction of chloroplast SSR variability was detected in cultivated materials, where only two alleles were conserved out of the four present in wild accessions. Contrarily, at nuclear level, high variability exist in the collection where the analysis of 11 SSR loci allowed the detection of a total of 91 different alleles. A Bayesian analysis performed on nuclear SSR data revealed that studied materials belong to two main clusters. While wild materials are equally represented in both clusters, the domesticated forms are mostly belonging to cluster P2 which is characterized by lower genetic diversity compared to the cluster P1. In the Neighbour Joining tree no clear distinction was found between accessions with the exception of those from China and Mongolia that were clearly separated from all the others.
草地早熟禾是一种适应广泛的中生至湿润生境的饲用和草坪草种。由于其基因组复杂性，关于该物种的进化、基因组组成和种内系统发育关系知之甚少。在本研究中，我们使用核分子标记和叶绿体分子标记以及体细胞组织的流式细胞术，研究了来自23个不同国家的33份草地早熟禾材料的形态和遗传多样性。目的是阐明包括栽培和野生材料在内的该收集物的遗传多样性和系统发育关系。形态特征表明，能够区分栽培型和野生型的最相关性状是春季生长习性和叶片颜色。基因组大小分析表明，野生和栽培材料在材料内部和材料之间都存在高度变异性。叶绿体trnL-F区域的序列分析显示多态性水平较低，这可能是该物种复杂繁殖方式的结果。此外，在栽培材料中检测到叶绿体SSR变异性大幅降低，野生材料中存在的四个等位基因在栽培材料中仅保留了两个。相反，在核水平上，该收集物中存在高度变异性，对11个SSR位点的分析共检测到91个不同等位基因。对核SSR数据进行的贝叶斯分析表明，研究材料属于两个主要类群。虽然野生材料在两个类群中分布均衡，但驯化形式大多属于类群P2，与类群P1相比，其遗传多样性较低。在邻接树中，除了来自中国和蒙古的材料明显与其他所有材料分开外，未发现材料之间有明显区分。
