Regulation of compound leaf development in mungbean (Vigna radiata L.) by CUP-SHAPED COTYLEDON/NO APICAL MERISTEM (CUC/NAM) gene

Planta. 2019 Mar;249(3):765-774. doi: 10.1007/s00425-018-3038-z. Epub 2018 Nov 2.

Abstract

The results provide a significant verification of functional redundancy and diversity of CUC/NAM genes in legumes. The CUP-SHAPED COTYLEDON/NO APICAL MERISTEM (CUC/NAM) orthologs play key roles for plant organ boundary formation and organ development. Here, we performed a forward screen of the gamma irradiation mutagenesis population in mungbean and characterised a mutant, reduced rachis and fused leaflets (rrf1), which gave rise to the formation of compound leaves with reduced rachis and fused leaflets. Map-based cloning revealed that RRF1 encoded a CUC/NAM protein in mungbean. Phylogenetic analysis indicated that legume CUC1/CUC2 genes were classified as belonging to two subclades, and there are different copies of CUC1/CUC2 genes in legumes. Transcriptomic analysis showed that expression levels of a set of developmental regulators, including class I KNOTTED-LIKE HOMEOBOXI (KNOXI) gene and LATERAL ORGAN BOUNDARIES DOMAIN (LBD) gene, were altered in rrf1 mutants compared to the wild-type plants. Furthermore, rrf1 genetically interacted with heptafoliate leaflets1 (hel1), a mutant displaying a seven-leaflet compound leaf, to regulate leaf development in mungbean. Our results suggest functional redundancy and diversity of two subclades of CUC1/CUC2 genes in legumes, following the duplication of an ancestral gene.

Keywords: Compound leaf; Genetic interaction; Molecular cloning; Mungbean; Plant organ boundary.

MeSH terms

  • Cloning, Molecular
  • Gene Expression Profiling
  • Gene Expression Regulation, Developmental / genetics
  • Gene Expression Regulation, Plant / genetics
  • Genes, Plant / genetics
  • Genes, Plant / physiology*
  • Phylogeny
  • Plant Leaves / genetics
  • Plant Leaves / growth & development*
  • Plant Proteins / genetics
  • Plant Proteins / physiology*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Vigna / genetics
  • Vigna / growth & development*

Substances

  • Plant Proteins