title: The MADS box genes SEEDSTICK and ARABIDOPSIS Bsister play a maternal role in fertilization and seed development.
abstract: The haploid generation of flowering plants develops within the sporophytic tissues of the ovule. After fertilization, the maternal seed coat develops in a coordinated manner with formation of the embryo and endosperm. In the arabidopsis bsister (abs) mutant, the endothelium, which is the most inner cell layer of the integuments that surround the haploid embryo sac, does not accumulate proanthocyanidins and the cells have an abnormal morphology. However, fertility is not affected in abs single mutants. SEEDSTICK regulates ovule identity redundantly with SHATTERPROOF 1 (SHP1) and SHP2 while a role in the control of fertility was not reported previously. Here we describe the characterization of the abs stk double mutant. This double mutant develops very few seeds due to both a reduced number of fertilized ovules and seed abortions later during development. Morphological analysis revealed a total absence of endothelium in this double mutant. Additionally, massive starch accumulation was observed in the embryo sac. The phenotype of the abs stk double mutant highlights the importance of the maternal-derived tissues, particularly the endothelium, for the development of the next generation.
authors.affiliation: Dipartimento di Biologia, Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Mizzotti
authors.forename: Marta Adelina
authors.initials: MA
authors.lastname: Mendes
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Caporali
authors.forename: Arp
authors.initials: A
authors.lastname: Schnittger
authors.forename: Martin M
authors.initials: MM
authors.lastname: Kater
authors.forename: Raffaella
authors.initials: R
authors.lastname: Battaglia
authors.forename: Lucia
authors.initials: L
authors.lastname: Colombo
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D005838:Genotype; D018525:Germination; D017403:In Situ Hybridization; D026161:MADS Domain Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D056771:Ovule / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D010641:Phenotype; D030821:Plants, Genetically Modified; D011003:Ploidies; D053205:Pollen Tube / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D054817:Pollination; D044945:Proanthocyanidins / Q000378:metabolism; D012639:Seeds / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D026161:MADS Domain Proteins; D044945:Proanthocyanidins; C476012:SEEDSTICK protein, Arabidopsis; C470417:TT16 protein, Arabidopsis; D014157:Transcription Factors