背景回顾：The Orchidaceae is of economic and ecological importance, and constitutes ~10% of all seed plant species. 

主要研究：Here, we report a genome physical map for Cymbidium sinense, a well-known species belonging to genus Cymbidium that has thousands of natural variation varieties of flower organs, flower and leaf colors, and also referred as the King of Fragrance, which make it arose into a unique cultural symbol in China. 

结果1-组装+注释：The high-quality chromosome-scale genome assembly was 3.52 Gb in size, 29,638 protein-coding genes were predicted, and evidence for whole-genome duplication shared with other orchids was provided. 

结果2-基因扩张：Marked amplification of cytochrome- and photosystem-related genes was observed, which was consistent with the shade tolerance and dark-green leaves of C. sinense. 

结果3-花性状与MADS基因：Extensive duplication of MADS-box genes, and the resulting subfunctional and expressional differentiation, were associated with regulation of species-specific flower traits, including wild-type and mutant-type floral patterning, seasonal flowering, and ecological adaption. CsSEP4 was originally found to positively regulate gynostemium development. The CsSVP genes and their interaction proteins CsAP1 and CsSOC1 were significantly expanded and involved in the regulation of low-temperature dependent flowering. 

结果4-其它重要性状：Important genetic clues to the colorful leaf traits, purple-black flowers and volatile trait in C. sinense were also found. 

结论：The results provide new insights into the molecular mechanisms of important phenotypic traits of Cymbidium and its evolution, and serve as a powerful platform for future evolutionary studies and molecular breeding of orchids.

 摘 要 

兰科植物具有重要的经济和生态价值，其物种数量约占整个种子植物的10%。本文中，作者报道了墨兰（Cymbidium sinense）的基因组物理图谱。墨兰是一种著名的兰属植物，具有数千种花器官、花色和叶色的自然变异品种，同时也被称为香水之王，使其成为了中国独特的文化象征。高质量的染色体级别墨兰基因组组装大小为3.52Gb，共预测了29638个蛋白编码基因，同时检测到了与其它兰花共享的全基因组复制事件。墨兰基因组中，与细胞色素和光系统相关的基因发生了显著的扩增，这与墨兰的耐阴性和深绿色叶片表型相一致。另外，作者发现墨兰的MADS-box基因发生了广泛的复制，以及随后发生了基因亚功能化和表达分化，这与物种特异性花性状的调节有关，包括野生型和突变体的成花模式、季节性开花以及生态适应。CsSEP4最初被发现能正向调节合蕊柱（兰科植物花中的雌蕊和雄蕊互相愈合所成的器官）的发育。CsSVP基因及其互作蛋白CsAP1和CsSOC1在墨兰基因组中发生了显著扩增，并参与了低温依赖性的开花调控。作者还鉴定了与墨兰彩色叶性状、紫黑色花以及花香味等重要性状相关的遗传基础。本文的研究结果为兰花重要表型性状的分子机制及其演化提供了新的见解，并为兰花未来的演化研究和分子育种提供了一个强有力的平台。