Articles
Two haplotype-resolved genomes of Hydrangea macrophylla reveal important flower traits for breeding improvement
Article number
1434_17
Pages
121 – 128
Language
English
Abstract
Hydrangeas are one of the most valuable woody plants in the nursery trade.
They are popular worldwide for their large, showy inflorescences.
Novel inflorescence shapes and flower forms are highly desired by breeders, producers, and retail consumers, yet little is known about the genetic regulation of inflorescence or flower development in hydrangea.
The objectives of this research are to 1) generate a high-quality, chromosome level genome assembly for bigleaf hydrangea, and 2) integrate this genome assembly with other genomic tools to identify candidate genes for inflorescence type and double-flowering in bigleaf hydrangea.
Two high-quality reference genomes of hydrangea cultivars ‘Veitchii’ and ‘Endless Summer’ were assembled using PacBio long read sequencing.
The ‘Veitchii’ and ‘Endless Summer’ genomes are 2.21 and 2.22 Gb, respectively, each scaffolded into 18 pseudochromosomes.
An F1 population between ’Veitchii’ and ‘Endless Summer’ was used for linkage mapping of the inflorescence shape trait using genotyping by sequencing.
By mapping highly selective markers associated with the inflorescence trait to both reference genomes, a gene located on chromosome 4 was identified as the candidate gene for inflorescence shape.
A novel gene located on chromosome 17 was identified as a candidate gene responsible for double flowering.
The genome resources and the candidate genes presented here will help researchers and breeders determine genetic mechanisms driving flowering characteristics and floral development to develop high-value hydrangea cultivars for the nursery industry and the public.
They are popular worldwide for their large, showy inflorescences.
Novel inflorescence shapes and flower forms are highly desired by breeders, producers, and retail consumers, yet little is known about the genetic regulation of inflorescence or flower development in hydrangea.
The objectives of this research are to 1) generate a high-quality, chromosome level genome assembly for bigleaf hydrangea, and 2) integrate this genome assembly with other genomic tools to identify candidate genes for inflorescence type and double-flowering in bigleaf hydrangea.
Two high-quality reference genomes of hydrangea cultivars ‘Veitchii’ and ‘Endless Summer’ were assembled using PacBio long read sequencing.
The ‘Veitchii’ and ‘Endless Summer’ genomes are 2.21 and 2.22 Gb, respectively, each scaffolded into 18 pseudochromosomes.
An F1 population between ’Veitchii’ and ‘Endless Summer’ was used for linkage mapping of the inflorescence shape trait using genotyping by sequencing.
By mapping highly selective markers associated with the inflorescence trait to both reference genomes, a gene located on chromosome 4 was identified as the candidate gene for inflorescence shape.
A novel gene located on chromosome 17 was identified as a candidate gene responsible for double flowering.
The genome resources and the candidate genes presented here will help researchers and breeders determine genetic mechanisms driving flowering characteristics and floral development to develop high-value hydrangea cultivars for the nursery industry and the public.
Authors
L.W. Alexander, X. Wu, A. Hulse-Kemp, S.A. Simpson, R.C. Youngblood, X.F. Liu, B.E. Scheffler, T.A. Rinehart
Keywords
bigleaf hydrangea, double flower, BAM3, CYP78A5, flower development, floral regulation
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