New genetic details may help roses come up smelling like, well, roses

‘Old Blush’ genes hold secrets to biochemistry of scent and long-lived blooms

heirloom rose called Old Blush

OLD BLUSH  An analysis of rose genes, including of those in this heirloom rose called Old Blush, identifies overlooked ways the plants make some of their sweet-smelling compounds.  

M. Bendahmane

There’s new hope for making modern roses smell sweeter than the florist paper they’re wrapped in.

By decoding the genetics of an heirloom variety, a fragrant pink China rose called “Old Blush,” an international team of researchers has uncovered some new targets to tweak. That roster of genes plus an analysis of scent revealed at least 22 previously uncharacterized biochemical steps the plants can use to make terpene compounds, which help give roses their perfume, researchers report April 30 in Nature Ge­­­netics.

Modern roses have had a crazy history of blending genes from eight to 20 species, so decoding the DNA hodgepodge has been difficult. Rose breeders have opted for “showy plants,” says molecular geneticist Mohammed Bendahmane of École Normale Supérieure in Lyon, France. In the process, fragrances dwindled, and efforts to build them back in have not been fabulous.

The new paper focused on Rosa chinensis, one of the major contributors to modern hybrids, now mixed with European and Middle Eastern lineages of roses. The study’s new details clarify that some of the rose’s genes work in opposition to one other, with some turning on to brew a scent component while others shut down manufacture of anthocyanin pigments needed for rosy petals. Knowing this could help modern rose breeders resolve a trade-off that has sacrificed scent for color.

Examining one of the early hybrids, called La France, also suggests the China rose contributed the genes for the prized trait of prolonged blooming. And the genetic survey turned up genes that might inspire ways to make the plants more water efficient and last longer in a vase.  

Susan Milius is the life sciences writer, covering organismal biology and evolution, and has a special passion for plants, fungi and invertebrates. She studied biology and English literature.

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