title: Expressions of ECE-CYC2 clade genes relating to abortion of both dorsal and ventral stamens in Opithandra (Gesneriaceae).
abstract: BACKGROUND
  ECE-CYC2 clade genes known in patterning floral dorsoventral asymmetry (zygomorphy) in Antirrhinum majus are conserved in the dorsal identity function including arresting the dorsal stamen. However, it remains uncertain whether the same mechanism underlies abortion of the ventral stamens, an important morphological trait related to evolution and diversification of zygomorphy in Lamiales sensu lato, a major clade of predominantly zygomorphically flowered angiosperms. Opithandra (Gesneriaceae) is of particular interests in addressing this question as it is in the base of Lamiales s.l., an early representative of this type zygomorphy.
  
  
  RESULTS
  We investigated the expression patterns of four ECE-CYC2 clade genes and two putative target cyclinD3 genes in Opithandra using RNA in situ hybridization and RT-PCR. OpdCYC gene expressions were correlated with abortion of both dorsal and ventral stamens in Opithandra, strengthened by the negatively correlated expression of their putative target OpdcyclinD3 genes. The complement of OpdcyclinD3 to OpdCYC expressions further indicated that OpdCYC expressions were related to the dorsal and ventral stamen abortion through negative effects on OpdcyclinD3 genes.
  
  
  CONCLUSIONS
  These results suggest that ECE-CYC2 clade TCP genes are not only functionally conserved in the dorsal stamen repression, but also involved in arresting ventral stamens, a genetic mechanism underlying the establishment of zygomorphy with abortion of both the dorsal and ventral stamens evolved in angiosperms, especially within Lamiales s.l.
authors.affiliation: State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Xiangshan, Beijing 100093, PR China. cfsong@ibcas.ac.cn
authors.forename: Chun-Feng
authors.initials: CF
authors.lastname: Song
authors.forename: Qi-Bing
authors.initials: QB
authors.lastname: Lin
authors.forename: Rong-Hua
authors.initials: RH
authors.lastname: Liang
authors.forename: Yin-Zheng
authors.initials: YZ
authors.lastname: Wang
mesh_terms: D003001:Cloning, Molecular; D056743:Cyclin D3; D016213:Cyclins / Q000235:genetics; D004268:DNA-Binding Proteins; D035264:Flowers / Q000235:genetics / Q000254:growth & development*; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D050437:Genes, Developmental; D017343:Genes, Plant; D017403:In Situ Hybridization; D019684:Magnoliopsida / Q000235:genetics* / Q000254:growth & development; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics*; D018749:RNA, Plant / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D014157:Transcription Factors
chemical_list: D056743:Cyclin D3; D016213:Cyclins; D004268:DNA-Binding Proteins; D010940:Plant Proteins; D018749:RNA, Plant; D014157:Transcription Factors; C101995:cycloidea protein, Antirrhinum