Crataegus laevigata and C. monogyna sequences for SSRs development

Three Central European Crataegus species with natural occurance were investigated. C. monogyna and C. laevigata are predominantly diploid sexuals, while C. rhipidophylla is mainly polyploid with apomictic reproduction. These species hybridize in sympatry, resulting in hybrids such as C. x media (C. monogyna x C. laevigata), C. x macrocarpa (C. rhipidophylla x C. laevigata), and C. x subsphaerica (C. monogyna x C. rhipidophylla). The vast morphological variability makes it challenging to identify these taxa. To assess the relative contribution of hybridization, polyploidy and apomixis in shaping Central European Crataegi diversity, we collected leaves and fruits from 10 natural populations in areas where all three species coexist. We genotyped the mixed populations using nuclear microsatellites (SSRs) developed from High-throughput Sequencing and we estimated their ploidy levels using flow cytometry (FCM). A part of the study is also screening the seeds for the reproduction mode assessment (FCSS), and measuring of the morphological traits of leaves and fruits.

本研究针对3种自然分布于中欧的山楂属（Crataegus）物种展开了调查。其中单柱山楂（C. monogyna）与光果山楂（C. laevigata）以二倍体有性生殖为主要生殖方式，而复叶山楂（C. rhipidophylla）则多为具备无融合生殖特性的多倍体物种。上述物种在同域分布区域内可发生杂交，产生多个杂交类群，包括媒介山楂（C. × media，即C. monogyna × C. laevigata）、大果山楂（C. × macrocarpa，即C. rhipidophylla × C. laevigata）以及近球形山楂（C. × subsphaerica，即C. monogyna × C. rhipidophylla）。类群间丰富的形态变异为这些分类单元的鉴定带来了显著挑战。为解析杂交、多倍化与无融合生殖在塑造中欧山楂属物种多样性过程中的相对贡献，我们在3个物种同域共存的区域内，采集了10个自然种群的叶片与果实样本。我们利用高通量测序开发的核微卫星标记（Simple Sequence Repeats, SSRs）对混合种群进行了基因分型，并通过流式细胞术（Flow Cytometry, FCM）估算了各样本的倍性水平。此外，本研究还通过种子流式细胞术筛选（Flow Cytometry Seed Screening, FCSS）对种子的生殖模式进行评估，并测定了叶片与果实的多项形态性状。