Characterization of two SEPALLATA MADS-box genes from the dioecious plant Silene latifolia

Abstract

TwoSEPALLATAorthologs,SlSEP1andSlSEP3, were isolated from male flower buds of the dioecious plantSilene latifolia. Both genes are located on autosomes and not on the sex chromosomes.SlSEP1andSlSEP3transcripts were detected specifically in male and female flower buds. Quantitative RT-PCR and in situ hybridization revealed that both genes were expressed in young flower meristems, developing petals, male anthers, and female ovules. However, neither transcript was detected in suppressed gynoecia of male flower buds or suppressed anthers of female flower buds. The genes were differentially expressed during anther development, with theSlSEP1transcript accumulating in anther walls and tapetal cells, and theSlSEP3transcript accumulating in tetrads as well as anther walls and tapeta. Transcripts of both genes were also detected in flower buds of mutants with deletions of some parts of the Y chromosome, suggesting that neither gene is directly involved in sex determination.