Extensive allopolyploidy in the neotropical genus Lachemilla (Rosaceae) revealed by PCR-based target enrichment of the nuclear ribosomal DNA cistron and plastid phylogenomics.
Extensive allopolyploidy in the neotropical genus Lachemilla (Rosaceae) revealed by PCR-based target enrichment of the nuclear ribosomal DNA cistron and plastid phylogenomics.
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DOI：
10.1002/ajb2.1253
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发表时间：
2019-03
影响因子：
3
通讯作者：
Diego F. Morales‐Briones;David C. Tank
中科院分区：
文献类型：
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作者：
Diego F. Morales‐Briones;David C. Tank
研究前提多倍体长期以来一直被认为是植物进化的重要力量。以往的研究表明，在不同的新热带蔷薇属（蔷薇科）中，多倍体的广泛存在和异源多倍体的起源。尽管如此，这一证据主要依赖于细胞核不一致的模式，并且仍然需要核等位基因标记的直接证据。方法采用PCR靶富集与高通量测序相结合的方法，从48种拉克米拉（Lachemilla） 219份材料中获得核糖体（nr） DNA反链子的多个拷贝和45个质体基因组（cpDNA）区域，并探讨该群体物种的异源多倍体起源。我们鉴定出了33种Lachemilla的多个nrDNA核型，并建立了明确的异源多倍体证据，表明这种情况在Lachemilla属中是常见和广泛的。此外，我们还发现了三种自多倍体物种的证据。我们还建立了几个异源多倍体物种的多个独立起源。最后，仅基于cpDNA系统发育，我们确定单型属Farinopsis是Fragariinae亚族中Lachemilla的姊妹属和亲缘属。结论：我们的研究证明了核糖体DNA顺子在该区域协同进化未完成时检测同种异体多倍体的效用。此外，有了强健的叶绿体系统发育，可以确定杂交事件的方向，并可以确定多个独立的异源多倍体物种的起源。
PREMISE OF THE STUDY Polyploidy has been long recognized as an important force in plant evolution. Previous studies had suggested widespread occurrence of polyploidy and the allopolyploid origin of several species in the diverse neotropical genus Lachemilla (Rosaceae). Nonetheless, this evidence has relied mostly on patterns of cytonuclear discordance, and direct evidence from nuclear allelic markers is still needed. METHODS Here we used PCR target enrichment in combination with high throughput sequencing to obtain multiple copies of the nuclear ribosomal (nr) DNA cistron and 45 regions of the plastid genome (cpDNA) from 219 accessions representing 48 species of Lachemilla and to explore the allopolyploid origin of species in this group. KEY RESULTS We were able to identify multiple nrDNA ribotypes and establish clear evidence of allopolyploidy in 33 species of Lachemilla, showing that this condition is common and widespread in the genus. Additionally, we found evidence for three autopolyploid species. We also established multiple, independent origins of several allopolyploid species. Finally, based solely on the cpDNA phylogeny, we identified that the monotypic genus Farinopsis is the sister group of Lachemilla and allied genera within subtribe Fragariinae. CONCLUSIONS Our study demonstrates the utility of the nuclear ribosomal DNA cistron to detect allopolyploidy when concerted evolution of this region is not complete. Additionally, with a robust chloroplast phylogeny in place, the direction of hybridization events can be established, and multiple, independent origins of allopolyploid species can be identified.