The honeysuckle genome provides insight into the molecular mechanism of carotenoid metabolism underlying dynamic flower coloration

First author: Xiangdong Pu; Affiliations: Chinese Academy of Medical Sciences & Peking Union Medical College (中国医学科学院 & 北京协和医学院): Beijing, China

Corresponding author: Jingyuan Song

Lonicera japonica is a wide‐spread member of the Caprifoliaceae (honeysuckle) family utilized in traditional medical practices. This twining vine honeysuckle is also a much‐sought ornamental, in part due to its dynamic flower coloration, which changes from white to gold during development. The molecular mechanism underlying dynamic flower coloration in L. japonica was elucidated by integrating whole genome sequencing, transcriptomic analysis, and biochemical assays. Here, we report a chromosome‐level genome assembly of L. japonica, comprising nine pseudo‐chromosomes with a total size of 843.2 Mb. We also provide evidence for a whole genome duplication event in the lineage leading to L. japonica, which occurred after its divergence from Dipsacales and Asterales. Moreover, gene expression analysis not only revealed correlated expression of the relevant biosynthetic genes with carotenoid accumulation, but also suggested a role for carotenoid degradation in L. japonica’s dynamic flower coloration. The variation of flower color is consistent with not only the observed carotenoid accumulation pattern, but also with the release of volatile apocarotenoids that presumably serve as pollinator attractants. Beyond novel insights into the evolution and dynamics of flower coloration, the high‐quality L. japonica genome sequence also provides a foundation for molecular breeding to improve desired characteristics.

忍冬（学名：Lonicera japonica），又叫金银花，属于忍冬科（Caprifoliaceae）下的一个植物物种，常用于传统医疗实践。忍冬属于缠绕的藤蔓，其同时也是一种备受欢迎的观赏植物，部分是由于其具有动态的花色，忍冬的花在发育过程中会逐渐从白色变成金色。通过全基因组测序、转录组分析以及生化试验，作者研究了忍冬的花动态着色的分子机制。本文中，作者报道了忍冬的染色体级别参考基因组组装，包含9条拟染色体，大小约为843.2 Mb。基于忍冬的全基因组序列，作者发现忍冬在与川续断目（Dipsacales）和菊目（Asterales）分化后，发生过一次支系特异性的全基因组复制事件。此外，基因表达分析不仅揭示了与类胡萝卜素积累相关生物合成基因的相关性表达，同时也说明了类胡萝卜素降解在忍冬的花动态着色方面扮演重要作用。忍冬花色的变异不仅与观测的类胡萝卜素积累模式一致，同时还与作为传粉者引诱剂的挥发性阿朴类胡萝卜素（apocarotenoids）的释放相一致。本文所报道的忍冬基因组不仅为植物花色演化和动态波动提供了新的视野，同时也为针对该重要中草药植物未来特定性状改良的分子育种奠定了基础。

p.s. 阿朴类胡萝卜素（apocarotenoids）是类胡萝卜素的衍生分子，包括类异戊二烯在内的阿朴类胡萝卜素在植物-环境相互作用中发挥非常重要的功能，例如对授粉者的引诱以及对病原菌和草食动物的防御。 阿朴类胡萝卜素还包括挥发性芳香族化合物，可作为驱虫剂、化学引诱剂、生长模拟剂和抑制剂，以及植物激素脱落酸（abscisic acid）和独角金内酯（strigolactones）。【参考：Beltran J.C.M., Stange C. (2016) Apocarotenoids: A New Carotenoid-Derived Pathway. In: Stange C. (eds) Carotenoids in Nature. Subcellular Biochemistry, vol 79. Springer, Cham】

通讯：宋经元 (http://124.17.107.22/#type=experts;part_id=1044;party_id=16161)

个人简介：1987-1991年，中国农业大学，学士；1995-1998年，北京协和医学院，硕士；1999-2002年，北京协和医学院，博士。

研究方向：药用植物功能基因组、结构基因组与生物信息学分析、细胞培养与活性成分生产调控、中药DNA条形码鉴定。

doi: https://doi.org/10.1111/nph.16552

Journal: New Phytologist

Published date: March 18, 2020