Class B gene expression and the modified ABC model in nongrass monocots

Akira Kanno, Mutsumi Nakada, Yusuke Akita, Masayo Hirai

Research output: Contribution to journalReview articlepeer-review

52 Citations (Scopus)


The discovery of the MADS-box genes and the study of model plants such as Arabidopsis thaliana and Antirrhinum majus have greatly improved our understanding of the molecular mechanisms driving the diversity in floral development. The class B genes, which belong to the MADS-box gene family, are important regulators of the development of petals and stamens in flowering plants. Many nongrass monocot flowers have two whorls of petaloid organs, which are called tepals. To explain this floral morphology, the modified ABC model was proposed. This model was exemplified by the tulip, in which expansion and restriction of class B gene expression is linked to the transition of floral morphologies in whorl 1. The expression patterns of class B genes from many monocot species nicely fit this model; however, those from some species, such as asparagus, do not. In this review, we summarize the relationship between class B gene expression and floral morphology in nongrass monocots, such as Liliales (Liliaceae) and Asparagales species, and discuss the applicability of the modified ABC model to monocot flowers.

Original languageEnglish
Pages (from-to)268-279
Number of pages12
Publication statusPublished - 2007 Feb 19


  • Agapanthus praecox
  • Asparagus
  • Class B gene
  • Crocus sativus
  • Dendrobium crumenatum
  • Lily
  • Modified ABC model
  • Muscari armeniacum
  • Phalaenopsis equestris
  • Tricyrtis affinis
  • Tulip

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Environmental Science(all)


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