Bilateral symmetry of flowers is a relevant novelty that has occurred many times throughout the evolution of flowering plants. In Antirrhinum majus, establishment of flower dorso-ventral asymmetry is mainly due to interaction of TCP (CYC and DICH) and MYB (DIV, RAD and DRIF) transcription factors. In the present study, we characterized 8 DIV-, 4 RAD- and 2 DRIF-like genes from the transcriptome of Orchis italica, an orchid species with bilaterally symmetric and resupinate flowers. We found a similar number of DIV- and RAD-like genes within the genomes of Phalaenopsis equestris and Dendrobium catenatum orchids. Orchid DIV- and RAD-like proteins share conserved motifs whose distribution reflects their phylogeny and analysis of the genomic organization revealed a single intron containing many traces of transposable elements. Evolutionary analysis has shown that purifying selection acts on the DIV- and RAD-like coding regions in orchids, with relaxation of selective constraints in a branch of the DIV-like genes. Analysis of the expression patterns of DIV- and RAD-like genes in O. italica revealed possible redundant functions for some of them. In the perianth of O. italica, the ortholog of DIV and DRIF of A. majus are expressed in all tissues, whereas RAD is mainly expressed in the outer tepals and lip. These data allow for proposal of an evolutionary conserved model in which the expression of the orthologs of the DIV, RAD and DRIF genes might be related to establishment of flower bilateral symmetry in the non-model orchid species O. italica.

Transcriptome-wide identification and expression analysis of DIVARICATA- and RADIALIS-like genes of the Mediterranean orchid Orchis italica.

VALOROSO, MARIA CARMEN;DE PAOLO, SOFIA;IAZZETTI, GIOVANNI;ACETO, SERENA
2017

Abstract

Bilateral symmetry of flowers is a relevant novelty that has occurred many times throughout the evolution of flowering plants. In Antirrhinum majus, establishment of flower dorso-ventral asymmetry is mainly due to interaction of TCP (CYC and DICH) and MYB (DIV, RAD and DRIF) transcription factors. In the present study, we characterized 8 DIV-, 4 RAD- and 2 DRIF-like genes from the transcriptome of Orchis italica, an orchid species with bilaterally symmetric and resupinate flowers. We found a similar number of DIV- and RAD-like genes within the genomes of Phalaenopsis equestris and Dendrobium catenatum orchids. Orchid DIV- and RAD-like proteins share conserved motifs whose distribution reflects their phylogeny and analysis of the genomic organization revealed a single intron containing many traces of transposable elements. Evolutionary analysis has shown that purifying selection acts on the DIV- and RAD-like coding regions in orchids, with relaxation of selective constraints in a branch of the DIV-like genes. Analysis of the expression patterns of DIV- and RAD-like genes in O. italica revealed possible redundant functions for some of them. In the perianth of O. italica, the ortholog of DIV and DRIF of A. majus are expressed in all tissues, whereas RAD is mainly expressed in the outer tepals and lip. These data allow for proposal of an evolutionary conserved model in which the expression of the orthologs of the DIV, RAD and DRIF genes might be related to establishment of flower bilateral symmetry in the non-model orchid species O. italica.
File in questo prodotto:
File Dimensione Formato  
2017 Genome Biology and Evolution.pdf

accesso aperto

Licenza: Creative commons
Dimensione 1.53 MB
Formato Adobe PDF
1.53 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11588/677306
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 11
  • ???jsp.display-item.citation.isi??? 9
social impact