背景回顾：Bletilla striata, commonly known as baiji, is a species used in traditional Chinese medicine; it is highly regarded for its medicinal applications and therefore has high economic value. 

主要研究：Here, we report a high-quality haplotype-resolved genome of B.  striata, haplotype  A (2.37 Gb, with a scaffold N50 of 146.39 Mb and a contig N50 of 1.65 Mb) and haplotype  B (2.43 Gb, with a scaffold N50 of 150.22 Mb and a contig N50 of 1.66 Mb), assembled from high-fidelity (HiFi) reads and chromosome conformation capture (Hi-C) reads. 

结果1-基因组演化：We find evidence that B. striata has undergone two whole-genome duplication (WGD) events: an ancient WGD event shared by most monocots and a recent WGD event unique to all orchids. We also reconstructed the ancestral orchid karyotype (AOK) of 18 ancient chromosomes and the evolutionary trajectories of 16 modern B.  striata chromosomes. Comparative genomic analysis suggests that the expanded gene families of B.  striata might play important roles in secondary metabolite biosynthesis and environmental adaptation.

结果2-药用性状相关基因：By combining genomic and transcriptomic data, we identified the 10 core members from nine gene families that were probably involved in B.  striata polysaccharide(BSP) biosynthesis. Based on virus-induced gene silencing (VIGS) and yeast two-hybrid experiments, we present an MYB transcription factor (TF), BsMYB2, that can regulate BSP biosynthesis by directly interacting with eight key BSP-related genes: sacA1, HK1, scrK1, scrK2, GPI1, manA1, GMPP1 and UGP2_1.

结论：Our study will enhance the understanding of orchid evolution and accelerate the molecular-assisted breeding of B. striata for improving traits of medicinal value.

 摘 要 

白芨（Bletilla striata）是一个传统的中国药用植物，因其药用价值比较高，具有很高的经济价值。本文中，作者通过HiFi测序和Hi-C测序，获得了一个高质量、单倍型分辨率的白芨基因组，其中A和B套基因组分别大小为2.37Gb和2.43Gb，scaffold N50分别长146.39Mb和150.22Mb，contig N50分别长1.65Mb和1.66Mb。作者发现白芨基因组经历了两次全基因组复制事件，一次是由大多数单子叶植物共享的祖先WGD，一次是所有兰科植物共享的WGD。作者利用18个祖先染色体重构了兰科植物祖先染色体，以及16条现代白芨染色体的演化历史。比较基因组分析显示，白芨基因组上扩张的基因家族主要参与次生代谢物的生物合成和环境适应性。通过结合基因组和转录组分析，作者从9个基因家族中鉴定到了10个核心成员，可能参与白芨的多糖生物合成。基于病毒诱导的基因沉默VIGS和酵母双杂实验，作者发现了一个MYB转录因子BsMYB2能够直接促进8个多糖生物合成相关基因的表达，调控多糖的生物合成。本文的研究结果能够增加我们对于兰科植物演化的理解，加速白芨的分子辅助育种，提升药用价值相关的性状改良。