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Flower color variation in Chrysanthemum × morifolium is an important horticultural trait. This study identifies a natural bud sprout mutant of chrysanthemum cultivar Hanluhong (HLH) which normally produces red flowers. In the mutant (hlh), the tip of the petals turn golden yellow and gradually turn yellow from tip to the base. After two years of consecutive propagation through cuttings, the mutant traits were stable. Here, the contents of carotenoids and anthocyanidins were determined by HPLC-MS/MS. Compared to HLH, the hlh displayed significantly higher contents of lutein. Then we comparatively analyzed the transcriptome of the ray florets tissues during three flower developmental stages. Higher number of stage specific DEGs were found in mutant cultivar as compared to wild type. About 200 DEGs were filtered related to the metabolism of flavonoids, carotenoids, terpenoids, and anthocyanins. Combined with weighted gene co-expression network analysis (WGCNA) and qRT-PCR verification, CHI, DFR, ANS and CCD4 genes involved in anthocyanins biosynthesis and carotenoids degradation were identified as candidate genes. Among the transcription factors, MYB, bHLH and WD40 members showed significant expression variations between the two cultivars. These results improve our understanding of flower color variation especially red and yellow color transition in chrysanthemum. |
