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Article|01 Jul 2020|OPEN
A chromosome-scale reference genome of Aquilegia oxysepala var. kansuensis
Jinghe Xie1,2, Haifeng Zhao1,2, Kunpeng Li1,2, Rui Zhang1, Yongchao Jiang1, Meimei Wang1,2, Xuelian Guo1, Ben Yu1,2, Hongzhi Kong1,2,, Yuannian Jiao1,2, & Guixia Xu1,2,
1State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
2University of Chinese Academy of Sciences, Beijing 100049, China

Horticulture Research 7,
Article number: 20113 (2020)
doi: 10.1038/hortres.2020.113
Views: 119

Received: 29 Feb 2020
Revised: 20 Apr 2020
Accepted: 05 May 2020
Published online: 01 Jul 2020

Abstract

The genus Aquilegia (Ranunculaceae) has been cultivated as ornamental and medicinal plants for centuries. With petal spurs of strikingly diverse size and shape, Aquilegia has also been recognized as an excellent system for evolutionary studies. Pollinator‐mediated selection for longer spurs is believed to have shaped the evolution of this genus, especially the North American taxa. Recently, however, an opposite evolutionary trend was reported in an Asian lineage, where multiple origins of mini- or even nonspurred morphs have occurred. Interesting as it is, the lack of genomic resources has limited our ability to decipher the molecular and evolutionary mechanisms underlying spur reduction in this special lineage. Using long-read sequencing (PacBio Sequel), in combination with optical maps (BioNano DLS) and Hi–C, we assembled a high-quality reference genome of A. oxysepala var. kansuensis, a sister species to the nonspurred taxon. The final assembly is approximately 293.2 Mb, 94.6% (277.4 Mb) of which has been anchored to 7 pseudochromosomes. A total of 25,571 protein-coding genes were predicted, with 97.2% being functionally annotated. When comparing this genome with that of A. coerulea, we detected a large rearrangement between Chr1 and Chr4, which might have caused the Chr4 of A. oxysepala var. kansuensis to partly deviate from the “decaying” path that was taken before the split of Aquilegia and Semiaquilegia. This high-quality reference genome is fundamental to further investigations on the development and evolution of petal spurs and provides a strong foundation for the breeding of new horticultural Aquilegia cultivars.