Gaillardia plants have been widely cultivated in China and have become an important component of garden landscaping. Different from the common ligulate ray floret, the cornflower-like (funnel-shaped) ray floret is a special phenotype variation in Gaillardia species. Previous studies revealed that CYC-like genes could shape the floret phenotype in Compositae. To reveal the molecular mechanism of the cornflower-like phenotype, we checked the capitulum transcriptomes of several cultivars of Gaillardia that possess different ray florets. As a result, we identified 11 CYC-like genes, of which five included complete coding region sequences. Phylogenetic analysis revealed that all five genes were CYC2-like genes. Relative expression analysis of RNA-resequencing reads, qRT-PCR comparison, and gene-silencing treatment all showed that the CYC2c gene is the main genetic mechanism responsible for the shaping of the cornflower-like ray floret phenotype in Gaillardia cultivars. This study expounded our understanding of flower morphology evolution and provides useful insights for improving Compositae breeding.
Keywords: Blanket flower; CYCLOIDEA gene; Funnel-shaped florets.
© 2022. The Author(s) under exclusive licence to The Botanical Society of Japan.