Extensive allopolyploidy in the neotropical genus Lachemilla (Rosaceae) revealed by PCR ‐based target enrichment of the nuclear ribosomal DNA cistron and plastid phylogenomics

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 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 aut...研究背景：多倍体化长期以来被视为植物演化的重要驱动力。既往研究显示，在物种多样的新热带Lachemilla属（蔷薇科Rosaceae）中，多倍体化现象广泛分布，且该属多个物种为异源多倍体起源。不过，此前的相关证据多基于核质不一致（cytonuclear discordance）的模式，目前仍缺乏核等位基因标记层面的直接佐证。 研究方法：本研究结合PCR靶向富集与高通量测序技术，对涵盖48个物种的219份Lachemilla属样品开展测序，获取了核核糖体（nuclear ribosomal, nr）DNA顺反子的多个拷贝以及质体基因组（cpDNA）的45个区域序列，以此探究该属物种的异源多倍体起源机制。 主要结果：本研究成功鉴定出多种核核糖体DNA核糖体型，并在33个Lachemilla属物种中获得了明确的异源多倍化证据，证实该现象在该属中普遍且广泛存在。此外，本研究还发现了3个