Species-specific genes account for the differences in floral transition between continuous-flowering and once-flowering roses

Abstract

Floral transitions in continuous-flowering Rosa chinensis ‘Old Blush’ and once-flowering R. odorata var. gigantea were analyzed using comparative transcriptome. In total, 3208 and 5825 species-specific unigenes were identified in the transcriptome profiles of ‘Old Blush’ and R. odorata var. gigantea, respectively. Furthermore, these species-specific unigenes were annotated by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis, and the Mercator web tool was used to mine vital metabolic processes. The contents of soluble sugar and starch in ‘Old Blush’ were higher than those in R. odorata var. gigantea at each stage during the floral transition process. The soluble sugar content was negatively correlated with the starch content in ‘Old Blush’. Therefore, we concluded that the vegetative-to-reproductive phase transition of ‘Old Blush’ was largely controlled by carbon metabolism, especially trehalose. In contrast, the floral transition of R. odorata var. gigantea was potentially mediated by low temperatures (vernalization) and the hexose-mediated miR156 pathway.