The S locus-linked Primula homeotic mutant sepaloid shows characteristics of a B-function mutant but does not result from mutation in a B-function gene.
Floral homeotic and flower development mutants of Primula, including double, Hose in Hose, Jack in the Green and Split Perianth, have been cultivated since the late 1500s as ornamental plants but until recently have attracted limited scientific attention. Here we describe the characterization of a new mutant phenotype, sepaloid, that produces flowers comprising only sepals and carpels. The sepaloid mutation is recessive, and is linked to the S locus that controls floral heteromorphy. The phenotype shows developmental variability, with flowers containing three whorls of sepals surrounding fertile carpels, two whorls of sepals with a diminished third whorl of sepals surrounding a fourth whorl of carpels, or three whorls of sepals surrounding abnormal carpels. In some respects, these phenotypes resemble the Arabidopsis and Antirrhinum homeotic B-function mutants apetala3/deficiens (ap3/def) and pistillata/globosa (pi/glo). We have isolated the Primula vulgaris B-function genes PvDEFICIENS (PvDEF) and PvGLOBOSA (PvGLO), expression of both of which is affected in the sepaloid mutant. PvGLO, like sepaloid, is linked to the S locus, whereas PvDEF is not. However, our analyses reveal that sepaloid and PvGLO represent different genes. We conclude that SEPALOID is an S-linked independent regulator of floral organ identity genes including PvDEF and PvGLO.
Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
Jinhong
J
Li
Margaret
M
Webster
Brigitta
B
Dudas
Holly
H
Cook
Iain
I
Manfield
Brendan
B
Davies
Philip M
PM
Gilmartin
D000483:Alleles; D003001:Cloning, Molecular; D026281:DEFICIENS Protein / Q000235:genetics*; D018076:DNA, Complementary / Q000235:genetics; D035264:Flowers / Q000033:anatomy & histology* / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D015723:Gene Library; D017343:Genes, Plant; D018398:Homeodomain Proteins / Q000235:genetics*; D040582:Inheritance Patterns; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics*; D031825:Primula / Q000235:genetics*; D018749:RNA, Plant / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020539:Sequence Analysis, Protein; D020798:Two-Hybrid System Techniques
D026281:DEFICIENS Protein; D018076:DNA, Complementary; C102172:GLOBOSA protein, plant; D018398:Homeodomain Proteins; D010940:Plant Proteins; D018749:RNA, Plant