Laboratório de Citogenética e Citometria, Departamento de Biologia Geral, Universidade Federal de Viçosa, Viçosa, MG, ZIP 36.570-900, Brazil.
Laboratório de Citogenética e Cultura de Tecidos Vegetais, Campus de Alegre, Universidade Federal Do Espírito Santo, Alegre, ES, ZIP 29.500-000, Brazil.
Planta. 2022 May 2;255(6):112. doi: 10.1007/s00425-022-03898-z.
Coffea karyotype organization and evolution has been uncovered by classical cytogenetics and cytogenomics. We revisit these discoveries and present new karyotype data. Coffea possesses ~ 124 species, including C. arabica and C. canephora responsible for commercial coffee production. We reviewed the Coffea cytogenetics, from the first chromosome counting, encompassing the karyotype characterization, chromosome DNA content, and mapping of chromosome portions and DNA sequences, until the integration with genomics. We also showed new data about Coffea karyotype. The 2n chromosome number evidenced the diploidy of almost all Coffea, and the C. arabica tetraploidy, as well as the polyploidy of other hybrids. Since then, other genomic similarities and divergences among the Coffea have been shown by karyotype morphology, nuclear and chromosomal C-value, AT and GC rich chromosome portions, and repetitive sequence and gene mapping. These cytogenomic data allowed us to know and understand the phylogenetic relations in Coffea, as well as their ploidy level and genomic origin, highlighting the relatively recent allopolyploidy. In addition to the euploidy, the role of the mobile elements in Coffea diversification is increasingly more evident, and the comparative analysis of their structure and distribution on the genome of different species is in the spotlight for future research. An integrative look at all these data is fundamental for a deeper understanding of Coffea karyotype evolution, including the key role of polyploidy in C. arabica origin. The 'Híbrido de Timor', a recent natural allotriploid, is also in the spotlight for its potential as a source of resistance genes and model for plant polyploidy research. Considering this, we also present some unprecedented results about the exciting evolutionary history of these polyploid Coffea.
经典细胞遗传学和细胞基因组学揭示了咖啡的核型组织和进化。我们重新审视这些发现并呈现新的核型数据。咖啡拥有约 124 个种，包括商业化咖啡生产的咖啡阿拉比卡和咖啡罗布斯塔。我们综述了咖啡的细胞遗传学，从最初的染色体计数开始，涵盖了核型特征、染色体 DNA 含量、染色体部分和 DNA 序列的作图，直至与基因组学的整合。我们还展示了有关咖啡核型的新数据。2n 染色体数证明了几乎所有咖啡都是二倍体，咖啡阿拉比卡是四倍体，以及其他杂种是多倍体。从那时起，核型形态、核和染色体 C 值、富含 AT 和 GC 的染色体部分以及重复序列和基因作图等方面显示了咖啡之间的其他基因组相似性和分化。这些细胞基因组学数据使我们能够了解和理解咖啡的系统发育关系，以及它们的倍性水平和基因组起源，突出了相对较新的异源多倍体。除了整倍体之外，移动元件在咖啡多样化中的作用越来越明显，不同物种基因组上的结构和分布的比较分析是未来研究的焦点。综合考虑所有这些数据对于深入了解咖啡核型进化至关重要，包括多倍体在咖啡阿拉比卡起源中的关键作用。最近的自然异源三倍体“帝汶杂种”因其作为抗性基因的来源和植物多倍体研究模型的潜力而备受关注。有鉴于此，我们还介绍了一些关于这些多倍体咖啡令人兴奋的进化历史的前所未有的结果。
