title: An allotetraploid Brassica napus early-flowering mutant has BnaFLC2-regulated flowering.
abstract: BACKGROUND
  Flowering time is an important agronomic trait, and wide variation in flowering time exists among Brassica napus accessions. GX50 early-flowering mutant, induced from Brassica napus by Ethyl Methane Sulfonate (EMS), exhibits a remarkable early transition from vegetative to reproductive growth.
  
  
  RESULTS
  GX50 plants flowered about 60 days earlier than the control wild-type plant B. napus XY15 under greenhouse conditions. Cytological examination revealed that the GX50 plants form inflorescences as early as from 5 weeks old, flower primordium from 6 weeks old, and siliques from 10 weeks old, whereas 10-week-old XY15 plants are still at vegetative growth stage. To unravel the molecular mechanisms underlying the GX50 flowering phenotype, we analyzed the expression of several key regulatory genes. Expressions of all five BnaFLCs (BnaFLC1 to BnaFLC5), BnaFT and BnaSOC1 were detected. Interestingly, BnaFLCs expression levels were lower in GX50 than those in XY15. Among the five BnaFLCs, only the expression pattern of BnaFLC2 corresponded to the timing of floral organ differentiation in GX50. In agreement with previous knowledge that BnaFLCs repress expression of BnaFT and BnaSOC1, increased levels of BnaFT and BnaSOC1 were observed in GX50 compared with XY15.
  
  
  CONCLUSIONS
  BnaFLC2, but not the other BnaFLC genes, plays an important role in B. napus GX50 floral transition.
authors.affiliation: Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Utilization, Hunan Agricultural University, Changsha, 410128, Hunan, China; College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, 410128, Hunan, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Huang
authors.forename: Ling
authors.initials: L
authors.lastname: Jiang
authors.forename: Ying
authors.initials: Y
authors.lastname: Ruan
authors.forename: Wenhui
authors.initials: W
authors.lastname: Shen
authors.forename: Chunlin
authors.initials: C
authors.lastname: Liu
mesh_terms: D029688:Brassica napus / Q000235:genetics* / Q000254:growth & development; D035264:Flowers / Q000254:growth & development*; D015870:Gene Expression; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D026161:MADS Domain Proteins / Q000235:genetics*; D009154:Mutation; D063246:Organogenesis, Plant / Q000235:genetics*; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics*; D057891:Tetraploidy
chemical_list: D026161:MADS Domain Proteins; D010940:Plant Proteins
keywords: BnaFLC2; Brassica napus; cytological observations; early-flowering mutant