Lilium cultivars have a wide range of variation in floral scent phenotypes. Using gas chromatography–mass spectrometry (GC/MS) analyses of volatile emissions during the night, the floral scent compositions of 35 lily cultivars from seven different hybrid groups were studied. The results showed that there was a positive correlation between volatile emission levels and scent intensities. Nonscented lily cultivars belonging to Asiatic hybrids hardly emitted volatiles, light-scented Longiflorum × Asiatic hybrids emitted low levels of volatiles, and scented lily cultivars (belonging to Oriental, Trumpet, Longiflorum, Longiflorum × Oriental, and Oriental × Trumpet hybrids) emitted significantly high levels of volatiles. In general, the scent compositions of lily cultivars were similar within the same hybrid group, and the differences among hybrid groups reflect their pedigree. Monoterpenoids and benzenoids dominated the floral scents of most volatile-emitting lily cultivars, whereas monoterpenoids alone dominated the floral scents of some volatile-emitting lilies. Although various scent compounds were released from volatile-emitting lily cultivars, the dominant scent compounds were focused on three monoterpenoids [1.8-cineole, linalool, and (E)-β-ocimene] and one benzenoid (methyl benzoate). The scent traits of lily cultivars could be traced back to their parents.
Ying Kong, Jinrong Bai, Lixin Lang, Fang Bao, Xiaoying Dou, Huan Wang, and Hongzhong Shang
Xiaoying Dou, Jinrong Bai, Huan Wang, Ying Kong, Lixin Lang, Fang Bao, and Hongzhong Shang
Anthocyanins are major pigments responsible for the color of lily (Lilium sp.) flowers. Anthocyanin synthesis is part of the flavonoid metabolic pathway. Numerous transcription factors, including R2R3-MYBs, basic helix-loop-helix (bHLH), and tryptophan–aspartic acid repeat (also known as WD40 or WD repeat) proteins, known to regulate flavonoid biosynthesis have been identified in various plant species. However, there is limited information available on WD repeat proteins in lilies. In this study, we identified a WD repeat gene in the Oriental hybrid lily ‘Sorbonne’ (Lilium hybrid WD repeat, LhWDR). LhWDR contains no introns, and has a 1100–base pair open reading frame, encoding a putative protein of 370 amino acids. LhWDR was found to be localized in the cytoplasm of transgenic Arabidopsis thaliana root cells. Expression patterns of LhWDR in different organs and at different periods of lily tepal growth revealed that the expression levels of this gene are closely associated with anthocyanin accumulation. A yeast two-hybrid assay demonstrated that full-length LhWDR interacts with the 420 N-terminal amino acids of Lilium hybrid bHLH2. Interestingly, overexpression of LhWDR in A. thaliana led to an upregulation of the dihydroflavonol 4-reductase gene, which is an important structural gene downstream of the anthocyanin pathway. These results indicate that the WD repeat protein LhWDR might interact with a bHLH transcription factor to regulate anthocyanin biosynthesis.