A modified ABCDE model of flowering in orchids based on gene expression profiling studies of the moth orchid Phalaenopsis aphrodite

PLoS One. 2013 Nov 12;8(11):e80462. doi: 10.1371/journal.pone.0080462. eCollection 2013.

Abstract

Previously we developed genomic resources for orchids, including transcriptomic analyses using next-generation sequencing techniques and construction of a web-based orchid genomic database. Here, we report a modified molecular model of flower development in the Orchidaceae based on functional analysis of gene expression profiles in Phalaenopsis aphrodite (a moth orchid) that revealed novel roles for the transcription factors involved in floral organ pattern formation. Phalaenopsis orchid floral organ-specific genes were identified by microarray analysis. Several critical transcription factors including AP3, PI, AP1 and AGL6, displayed distinct spatial distribution patterns. Phylogenetic analysis of orchid MADS box genes was conducted to infer the evolutionary relationship among floral organ-specific genes. The results suggest that gene duplication MADS box genes in orchid may have resulted in their gaining novel functions during evolution. Based on these analyses, a modified model of orchid flowering was proposed. Comparison of the expression profiles of flowers of a peloric mutant and wild-type Phalaenopsis orchid further identified genes associated with lip morphology and peloric effects. Large scale investigation of gene expression profiles revealed that homeotic genes from the ABCDE model of flower development classes A and B in the Phalaenopsis orchid have novel functions due to evolutionary diversification, and display differential expression patterns.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cluster Analysis
  • Flowers / genetics*
  • Gene Expression Profiling*
  • Gene Expression Regulation, Plant*
  • MADS Domain Proteins / genetics
  • Models, Biological*
  • Multigene Family
  • Mutation
  • Orchidaceae / classification
  • Orchidaceae / genetics*
  • Organ Specificity / genetics
  • Phenotype
  • Phylogeny
  • Reproducibility of Results
  • Transcription Factors / genetics
  • Transcriptome*

Substances

  • MADS Domain Proteins
  • Transcription Factors

Grants and funding

This work was supported by funding from Academia Sinica (http://www.sinica.edu.tw), Taiwan, under the Development Program of Industrialization for Agricultural Biotechnology, project No. 102S0030008. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.