1Beijing Key Laboratory of Ornamental Plants Germplasm Innovation & Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of the Ministry of Education, School of Landscape Architecture, Beijing Forestry University, No. 35 East Qinghua Road, Beijing 100083, China 2Genomics and Genetic Engineering Laboratory of Ornamental Plants, Department of Horticulture, College of Agriculture and Biotechnology, Zhejiang University, No. 866 Yuhangtang Road, Hangzhou 310058, China 3Biomarker Technologies Co., Ltd, No. 12 Fuqian Street, Shunyi District, Beijing 101300, China 4State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, No. 20 Nanxincun, Beijing 100093, China 5University of Chinese Academy of Sciences, No.19(A) Yuquan Road, Beijing 100049, China 6State Key Laboratory of Crop Stress Adaptation and Improvement, Plant Germplasm Resources and Genetic Laboratory, Kaifeng Key Laboratory of Chrysanthemum Biology, School of Life Sciences, School of Agriculture, Henan University, Jinming Road, Kaifeng 475004, China *Corresponding author. E-mail: wzc@henu.edu.cn,jiaoyn@ibcas.ac.cn,zls83@zju.edu.cn,silandai@sina.com †Xiaohui Wen and Junzhuo Li,Lili Wang contributed equally to the study.
Received: 10 Apr 2021 Revised: 16 Sep 2021 Accepted: 17 Sep 2021 Published online: 20 Jan 2022
Abstract
Cultivated chrysanthemum (Chrysanthemum × morifolium Ramat.) is a beloved ornamental crop due to the diverse capitula types among varieties, but the molecular mechanism of capitulum development remains unclear. Here, we report a 2.60 Gb chromosome-scale reference genome of C. lavandulifolium, a wild Chrysanthemum species found in China, Korea and Japan. The evolutionary analysis of the genome revealed that only recent tandem duplications occurred in the C. lavandulifolium genome after the shared whole genome triplication (WGT) in Asteraceae. Based on the transcriptomic profiling of six important developmental stages of the radiate capitulum in C. lavandulifolium, we found genes in the MADS-box, TCP, NAC and LOB gene families that were involved in disc and ray floret primordia differentiation. Notably, NAM and LOB30 homologs were specifically expressed in the radiate capitulum, suggesting their pivotal roles in the genetic network of disc and ray floret primordia differentiation in chrysanthemum. The present study not only provides a high-quality reference genome of chrysanthemum but also provides insight into the molecular mechanism underlying the diverse capitulum types in chrysanthemum.
and Yuannian Jiao4,5 ,
