title: Plastid gene expression and plant development require a plastidic protein of the mitochondrial transcription termination factor family.
abstract: Plastids are DNA-containing organelles unique to plant cells. In Arabidopsis, one-third of the genes required for embryo development encode plastid-localized proteins. To help understand the role of plastids in embryogenesis and postembryonic development, we characterized proteins of the mitochondrial transcription termination factor (mTERF) family, which in animal models, comprises DNA-binding regulators of mitochondrial transcription. Of 35 Arabidopsis mTERF proteins, 11 are plastid-localized. Genetic complementation shows that at least one plastidic mTERF, BELAYA SMERT' (BSM), is required for embryogenesis. The main postembryonic phenotypes of genetic mosaics with the bsm mutation are severe abnormalities in leaf development. Mutant bsm cells are albino, are compromised in growth, and suffer defects in global plastidic gene expression. The bsm phenotype could be phenocopied by inhibition of plastid translation with spectinomycin. Plastid translation is essential for cell viability in dicotyledonous species such as tobacco but not in monocotyledonous maize. Here, genetic interactions between BSM and the gene encoding plastid homomeric acetyl-CoA carboxylase ACC2 suggest that there is a functional redundancy in malonyl-CoA biosynthesis that permits bsm cell survival in Arabidopsis. Overall, our results indicate that biosynthesis of malonyl-CoA and plastid-derived systemic growth-promoting compounds are the processes that link plant development and plastid gene expression.
authors.affiliation: Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium.
authors.forename: Elena
authors.initials: E
authors.lastname: Babiychuk
authors.forename: Klaas
authors.initials: K
authors.lastname: Vandepoele
authors.forename: Josef
authors.initials: J
authors.lastname: Wissing
authors.forename: Miguel
authors.initials: M
authors.lastname: Garcia-Diaz
authors.forename: Riet
authors.initials: R
authors.lastname: De Rycke
authors.forename: Hana
authors.initials: H
authors.lastname: Akbari
authors.forename: Jérôme
authors.initials: J
authors.lastname: Joubès
authors.forename: Tom
authors.initials: T
authors.lastname: Beeckman
authors.forename: Lothar
authors.initials: L
authors.lastname: Jänsch
authors.forename: Margrit
authors.initials: M
authors.lastname: Frentzen
authors.forename: Marc C E
authors.initials: MC
authors.lastname: Van Montagu
authors.forename: Sergei
authors.initials: S
authors.lastname: Kushnir
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D050976:Basic-Leucine Zipper Transcription Factors; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D018087:Plastids / Q000235:genetics / Q000378:metabolism*; D014176:Protein Biosynthesis / Q000502:physiology; D014026:Nicotiana / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D003313:Zea mays / Q000235:genetics / Q000254:growth & development / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D050976:Basic-Leucine Zipper Transcription Factors