title: Multiple loci and genetic interactions involving flowering time genes regulate stem branching among natural variants of Arabidopsis.
abstract: Shoot branching is a major determinant of plant architecture. Genetic variants for reduced stem branching in the axils of cauline leaves of Arabidopsis were found in some natural accessions and also at low frequency in the progeny of multiparent crosses. Detailed genetic analysis using segregating populations derived from backcrosses with the parental lines and bulked segregant analysis was used to identify the allelic variation controlling reduced stem branching. Eight quantitative trait loci (QTLs) contributing to natural variation for reduced stem branching were identified (REDUCED STEM BRANCHING 1-8 (RSB1-8)). Genetic analysis showed that RSB6 and RSB7, corresponding to flowering time genes FLOWERING LOCUS C (FLC) and FRIGIDA (FRI), epistatically regulate stem branching. Furthermore, FLOWERING LOCUS T (FT), which corresponds to RSB8 as demonstrated by fine-mapping, transgenic complementation and expression analysis, caused pleiotropic effects not only on flowering time, but, in the specific background of active FRI and FLC alleles, also on the RSB trait. The consequence of allelic variation only expressed in late-flowering genotypes revealed novel and thus far unsuspected roles of several genes well characterized for their roles in flowering time control.
authors.affiliation: State Key Laboratory of Genetic Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, China.
authors.forename: Xueqing
authors.initials: X
authors.lastname: Huang
authors.forename: Jia
authors.initials: J
authors.lastname: Ding
authors.forename: Sigi
authors.initials: S
authors.lastname: Effgen
authors.forename: Franziska
authors.initials: F
authors.lastname: Turck
authors.forename: Maarten
authors.initials: M
authors.lastname: Koornneef
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics; D001483:Base Sequence; D003433:Crosses, Genetic; D004843:Epistasis, Genetic; D035264:Flowers / Q000235:genetics* / Q000502:physiology*; D017343:Genes, Plant / Q000235:genetics*; D005819:Genetic Markers; D005838:Genotype; D007178:Inbreeding; D026161:MADS Domain Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D010641:Phenotype; D020161:Physical Chromosome Mapping; D018547:Plant Stems / Q000235:genetics / Q000254:growth & development*; D040641:Quantitative Trait Loci / Q000235:genetics*; D015203:Reproducibility of Results
chemical_list: D029681:Arabidopsis Proteins; C418902:At5g10140 protein, Arabidopsis; C414613:FRI protein, Arabidopsis; D005819:Genetic Markers; D026161:MADS Domain Proteins
keywords: QTL analysis; axillary meristems; epistasis; flowering time; natural variation