Nicotiana section Suaveolentes is the largest section of Nicotiana and is a monophyletic group of allotetraploid species. Most of the species are endemic to Australia, but three species occur on islands in the South Pacific as far east as French Polynesia and one species is native to Namibia. Here, we present phylogenetic results based on genome skimming, with near-complete taxon sampling and multiple accessions sampled for several species. These represent the first phylogenetic results for the section that include most recognized taxa, using wild-sourced material wherever possible. Despite known chromosome number and genome size changes in the section, there is little divergence in the ribosomal DNA operon (26S, 18.S and 5.8S plus associated spacers) and plastid genomes, with little to no taxonomic signal in plastome phylogenetic results and clear plastid-nuclear discordance. These results contrast with strong morphological differentiation (both floral and vegetative) between most of the core Australian taxa and obvious differences in ecological preferences. Together, these initial results portray Nicotiana section Suaveolentes as experiencing recent and ongoing radiation in the arid zone of Australia.

中文翻译：

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在最近的烟草部分Suaveolentes（茄科）放射中出现大量的质体-核不一致

烟草节Suaveolentes是最大的部分烟草并且是异源四倍体物种的单系群。大多数物种是澳大利亚特有的，但在远东至法属玻里尼西亚的南太平洋岛屿上有3种，而纳米比亚则有1种。在这里，我们介绍了基于基因组撇除的系统发育结果，包括接近完整的分类群采样和对几种物种的多份采样。这些代表了该部分的首次系统发育结果，其中包括大多数公认的分类单元，并尽可能使用野生来源的材料。尽管该部分的染色体数目和基因组大小已知变化，但核糖体DNA操纵子（26S，18.S和5.8S加上相关的间隔区）和质体基因组几乎没有差异，在质体组系统发育结果中几乎没有分类信号，并且清晰质体-核不一致。这些结果与大多数澳大利亚核心分类群之间的强烈形态差异（花卉和植物形态）以及生态偏好的明显差异形成鲜明对比。这些初步结果共同体现了烟草节Suaveolentes在澳大利亚干旱区经历了近期和持续的辐射。