The core regulatory networks and hub genes regulating flower development inChrysanthemum morifolium

Key Message The study has facilitated important insights into the regulatory networks involved in flower development in chrysanthemum (Asteraceae), and is informative with respect to the mechanism of flower shape determination. Chrysanthemum morifolium, valued as an ornamental species given the diversity of its inflorescence form, is viewed as a model for understanding flower development in the Asteraceae. Yet, the underlying regulatory networks remain largely unexplored. Here, a transcriptomic survey of theChrysanthemum morifoliumvariety 'Jinba' was undertaken to uncover the global gene expression profiles and identify the modules of co-transcribed genes associated with flower development. The weighted gene coexpression network analysis revealed important networks and hub genes including ray floret petals-specific coexpression network, disc floret petals-specific network, B and E class genes involved network andCYC2genes network. Three ray floret petal-specific hub genes were also strongly transcribed in the ray florets of a selection of six diverse varieties and especially so in those which form ligulate ray floret petals.CmCYC2cwas strongly transcribed in the distal and lateral regions of the ray floret petals, and also, along withCmCYC2d,in the tubular ray florets. Furthermore, CmOFP, belonging to the family of ovate proteins, was identified in theCYC2genes network. CmOFP can interact with CmCYC2d that physically interact with CmCYC2c. This work provides important insights into the regulatory networks involved in flower development in chrysanthemum, and is informative with respect to the mechanistic basis of the regulation of flower shape.