Abstract：
The Greater Cape Floristic Region (GCFR) is renowned for its exceptional biodiversity, accommodating over 11 000 plant species, notable degree of endemism, and substantial diversification within limited plant lineages, a phenomenon ascribed to historical radiation events. While both abiotic and biotic factors contribute to this diversification, comprehensive genomic alterations, recognized as pivotal in the diversification of angiosperms, are perceived as uncommon. This investigation focuses on the genus Pteronia, a prominent representative of the Asteraceae family in the GCFR. Employing NGS-based HybSeq and RADSeq methodologies, flow cytometry, karyology, and ecological modeling, we scrutinize the intricacies of its polyploid evolution. Phylogenetic reconstructions using 951 low-copy nuclear genes confirm Pteronia as a well-supported, distinct clade within the tribe Astereae. The ingroup displays a structure indicative of rapid radiation likely antedating polyploid establishment, with the two main groups demarcated by their presence or absence in the fynbos biome. Genome size analysis encompasses 1293 individuals across 347 populations, elucidating significant variation ranging from 6.1 to 34.2 pg (2C-value). Pteronia demonstrates substantially large genome sizes within Astereae and phanerophytes. Polyploidy is identified in 31% of the studied species, with four discerned ploidy levels (2x, 4x, 6x, 8x). Cytotypes exhibit marked distinctions in environmental traits, influencing their distribution across biomes and augmenting their niche differentiation. These revelations challenge the presumed scarcity of polyploidy in the Cape flora, underscoring the imperative need for detailed population studies. The intricate evolutionary history of Pteronia, characterized by recent polyploidy and genome size variation, contributes substantially to the comprehension of diversification patterns within the GCFR biodiversity hotspot.
摘要：
大开普省植物区（GCFR）以其特殊的生物多样性而闻名。容纳超过11000种植物，值得注意的地方性程度，以及在有限的植物谱系内的大量多样化，归因于历史辐射事件的现象。虽然非生物和生物因素都有助于这种多样化，全面的基因组改变，被认为是被子植物多样化的关键，被认为是不寻常的。这项调查的重点是翼龙属，GCFR中菊科的杰出代表。采用基于NGS的HybSeq和RADSeq方法，流式细胞术,核子学,和生态建模，我们仔细研究其多倍体进化的复杂性。使用951个低拷贝核基因的系统发育重建证实了Pteronia是一个很好的支持，部落中不同的进化枝。内群显示出一种结构，表明快速辐射可能导致多倍体建立，两个主要群体根据它们在fynbos生物群落中的存在或不存在而划分。基因组大小分析涵盖了347个种群的1293个个体，阐明从6.1到34.2pg（2C值）的显着变化。蝶藻在Astereae和phana生体中显示出相当大的基因组大小。在31%的研究物种中发现了多倍体，具有四个明显的倍性水平(2x，4x,6x,8x）。细胞类型在环境特征上表现出明显的区别，影响它们在生物群落中的分布，并增强它们的生态位分化。这些启示挑战了开普植物区系多倍体的假定稀缺性，强调了对详细人口研究的迫切需要。翼龙的错综复杂的进化史,以最近的多倍体和基因组大小变异为特征，大大有助于理解GCFR生物多样性热点内的多样化模式。
