González-Pérez Susana, Garcés-Claver Ana, Mallor Cristina, Sáenz de Miera Luis E, Fayos Oreto, Pomar Federico, Merino Fuencisla, Silvar Cristina
Department of Ecology, Plant and Animal Biology, University of Coruña, A Coruña, Spain.
Agrifood Research and Technology Centre of Aragón (CITA), Zaragoza, Spain.
PLoS One. 2014 Dec 29;9(12):e116276. doi: 10.1371/journal.pone.0116276. eCollection 2014.
The successful exploitation of germplasm banks, harbouring plant genetic resources indispensable for plant breeding, will depend on our ability to characterize their genetic diversity. The Vegetable Germplasm Bank of Zaragoza (BGHZ) (Spain) holds an important Capsicum annuum collection, where most of the Spanish pepper variability is represented, as well as several accessions of other domesticated and non-domesticated Capsicum spp from all over the five continents. In the present work, a total of 51 C. annuum landraces (mainly from Spain) and 51 accessions from nine Capsicum species maintained at the BGHZ were evaluated using 39 microsatellite (SSR) markers spanning the whole genome. The 39 polymorphic markers allowed the detection of 381 alleles, with an average of 9.8 alleles per locus. A sizeable proportion of alleles (41.2%) were recorded as specific alleles and the majority of these were present at very low frequencies (rare alleles). Multivariate and model-based analyses partitioned the collection in seven clusters comprising the ten different Capsicum spp analysed: C. annuum, C. chinense, C. frutescens, C. pubescens, C. bacatum, C. chacoense and C. eximium. The data clearly showed the close relationships between C. chinense and C. frutescens. C. cardenasii and C. eximium were indistinguishable as a single, morphologically variable species. Moreover, C. chacoense was placed between C. baccatum and C. pubescens complexes. The C. annuum group was structured into three main clusters, mostly according to the pepper fruit shape, size and potential pungency. Results suggest that the diversification of C. annuum in Spain may occur from a rather limited gene pool, still represented by few landraces with ancestral traits. This ancient population would suffer from local selection at the distinct geographical regions of Spain, giving way to pungent and elongated fruited peppers in the South and Center, while sweet blocky and triangular types in Northern Spain.
成功利用种质库（其中蕴藏着植物育种不可或缺的植物遗传资源）将取决于我们对其遗传多样性进行表征的能力。西班牙萨拉戈萨蔬菜种质库（BGHZ）保存着重要的辣椒（Capsicum annuum）种质收集品，其中代表了大部分西班牙辣椒的变异性，以及来自五大洲各地的其他几种已驯化和未驯化辣椒属物种的种质。在本研究中，使用覆盖整个基因组的39个微卫星（SSR）标记对保存在BGHZ的总共51个辣椒地方品种（主要来自西班牙）和9个辣椒物种的51份种质进行了评估。这39个多态性标记共检测到381个等位基因，每个位点平均有9.8个等位基因。相当一部分等位基因（41.2%）被记录为特异性等位基因，其中大多数以极低频率出现（稀有等位基因）。多变量和基于模型的分析将收集品划分为七个聚类，包括所分析的十个不同辣椒属物种：辣椒、中国辣椒、小米辣、毛辣椒、黄灯笼辣椒、查科辣椒和埃克西辣椒。数据清楚地显示了中国辣椒和小米辣之间的密切关系。卡德纳斯辣椒和埃克西辣椒作为一个单一的、形态上可变的物种无法区分。此外，查科辣椒位于黄灯笼辣椒和毛辣椒复合体之间。辣椒组主要根据辣椒果实形状、大小和潜在辣味分为三个主要聚类。结果表明，西班牙辣椒的多样化可能源于一个相当有限的基因库，目前仍由少数具有祖先特征的地方品种代表。这个古老的群体在西班牙不同地理区域会受到局部选择，从而在南部和中部产生辣味和长果形的辣椒，而在西班牙北部则产生甜块状和三角形的辣椒。
