title: AGL23, a type I MADS-box gene that controls female gametophyte and embryo development in Arabidopsis.
abstract: MADS-box transcription factors are key regulators of plant developmental processes. While the function of MIKC (type II) MADS-box genes has been intensively studied, only limited data are available for the other more recently identified classes of MADS-box genes, despite these latter comprising more than 60% of the Arabidopsis MADS-box gene family. Here we describe the function of AGL23, an Arabidopsis type I MADS-box gene belonging to the Malpha subfamily. We show that AGL23 plays an important role during development of the female gametophyte and embryo. The agl23-1 mutant forms a functional megaspore. However, at this stage female gametophyte development is arrested and the megaspore persists during subsequent phases of ovule development. Despite the incomplete penetrance of the female gametophyte defect, plants homozygous for the agl23-1 mutation were never identified. Analysis of developing seeds showed that embryos homozygous for the agl23-1 allele are albino and unable to give rise to viable plants. Electron microscopy analysis revealed that this phenotype is due to the absence of chloroplasts, strongly suggesting that AGL23 is involved in controlling the biogenesis of organelles during embryo development.
authors.affiliation: Dipartimento di Biologia, Università degli Studi di Milano, via Celoria 26, 20133 Milano, Italy.
authors.forename: Monica
authors.initials: M
authors.lastname: Colombo
authors.forename: Simona
authors.initials: S
authors.lastname: Masiero
authors.forename: Silvia
authors.initials: S
authors.lastname: Vanzulli
authors.forename: Paolo
authors.initials: P
authors.lastname: Lardelli
authors.forename: Martin M
authors.initials: MM
authors.lastname: Kater
authors.forename: Lucia
authors.initials: L
authors.lastname: Colombo
mesh_terms: D017360:Arabidopsis / Q000196:embryology / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002736:Chloroplasts / Q000378:metabolism; D003001:Cloning, Molecular; D018744:DNA, Plant / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D026161:MADS Domain Proteins / Q000235:genetics / Q000378:metabolism*; D012639:Seeds / Q000196:embryology / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D018744:DNA, Plant; D026161:MADS Domain Proteins