title: A complement of ten essential and pleiotropic arabidopsis COP/DET/FUS genes is necessary for repression of photomorphogenesis in darkness.
abstract: Two genetic screens, one for mutations resulting in photomorphogenic development in darkness and the other for mutants with fusca phenotype, have thus far identified six pleiotropic Arabidopsis COP/DET/FUS genes. Here, we characterized representative mutants that define four additional pleiotropic photomorphogenic loci and a null mutant allele of the previously defined DET1 locus. Dark-grown seedlings homozygous for these recessive mutations exhibit short hypocotyls and expanded cotyledons and are lethal before reaching reproductive development. Dark-grown mutant seedlings also display characteristic photomorphogenic cellular differentiation and elevated expression of light-inducible genes. In addition, analyses of plastids from dark-grown mutants reveal partial chloroplast differentiation and absence of etioplast development. Root vascular bundle cells of light-grown mutant seedlings develop chloroplasts, suggesting that these FUS gene products are important for suppression of chloroplast differentiation in light-grown roots. Double-mutant analyses indicate that these pleiotropic cop/det/fus mutations are epistatic to mutations in phytochromes, a blue-light photoreceptor, and a downstream regulatory component, HY5. Therefore, there is a complement of at least 10 essential and pleiotropic Arabidopsis genes that are necessary for repression of photomorphogenic development.
authors.affiliation: Graduate Program of Genetics, Yale University School of Medicine, New Haven, Connecticut 06520-8005, USA.
authors.forename: S F
authors.initials: SF
authors.lastname: Kwok
authors.forename: B
authors.initials: B
authors.lastname: Piekos
authors.forename: S
authors.initials: S
authors.lastname: Misera
authors.forename: X W
authors.initials: XW
authors.lastname: Deng
mesh_terms: D017360:Arabidopsis / Q000254:growth & development* / Q000528:radiation effects; D002454:Cell Differentiation / Q000235:genetics; D018548:Cotyledon / Q000254:growth & development; D003624:Darkness; D018506:Gene Expression Regulation, Plant; D005804:Genes, Lethal; D017343:Genes, Plant; D018525:Germination; D006720:Homozygote; D008027:Light; D008957:Models, Genetic; D009024:Morphogenesis / Q000235:genetics; D009154:Mutation; D010834:Phytochrome / Q000378:metabolism; D018087:Plastids / Q000502:physiology; D012333:RNA, Messenger / Q000032:analysis; D018749:RNA, Plant / Q000032:analysis; D015398:Signal Transduction
chemical_list: D012333:RNA, Messenger; D018749:RNA, Plant; D010834:Phytochrome