title: Role of B3 domain transcription factors of the AFL family in maize kernel filling.
abstract: In the dicot Arabidopsis thaliana, the B3 transcription factors, ABA-INSENSITIVE 3 (ABI3), FUSCA 3 (FUS3) and LEAFY COTYLEDON 2 (LEC2) are key regulators of seed maturation. This raises the question of the role of ABI3/FUS3/LEC2 (AFL) proteins in cereals, where not only the embryo but also the persistent endosperm accumulates reserve substances. Among the five ZmAFL genes identified in the maize genome, ZmAFL2 and ZmAFL3/ZmVp1 closely resemble FUS3 and ABI3, respectively, in terms of their sequences, domain structure and gene activity profiles. Of the three genes that fall into the LEC2 phylogenetic sub-clade, ZmAFL5 and ZmAFL6 have constitutive gene activity, whereas ZmAFL4, like LEC2, has preferential gene activity in pollen and seed, although its seed gene activity is restricted to the endosperm during reserve accumulation. Knock down of ZmAFL4 gene activity perturbs carbon metabolism and reduces starch content in the developing endosperm at 20 DAP. ZmAFL4 and ZmAFL3/ZmVp1 trans-activate a maize oleosin promoter in a heterologous moss system. In conclusion our results suggest, based on gene activity profiles, that the functions of FUS3 and ABI3 could be conserved between dicot and monocot species. In contrast, LEC2 function may have partially diverged in cereals where our findings provide first evidence of the specialization of ZmAFL4 for roles in the endosperm.
authors.affiliation: Université de Lyon, Ecole Normale Supérieure de Lyon, Université Lyon 1, Unité Reproduction et Développement des Plantes, F-69364 Lyon, France; INRA, UMR 879, Reproduction et Développement des Plantes, F-69364 Lyon, France; CNRS, UMR 5667, Reproduction et Développement des Plantes, F-69364 Lyon, France.
authors.forename: Aurélie
authors.initials: A
authors.lastname: Grimault
authors.affiliation: Université de Lyon, Ecole Normale Supérieure de Lyon, Université Lyon 1, Unité Reproduction et Développement des Plantes, F-69364 Lyon, France; INRA, UMR 879, Reproduction et Développement des Plantes, F-69364 Lyon, France; CNRS, UMR 5667, Reproduction et Développement des Plantes, F-69364 Lyon, France.
authors.forename: Ghislaine
authors.initials: G
authors.lastname: Gendrot
authors.affiliation: Université de Lyon, Ecole Normale Supérieure de Lyon, Université Lyon 1, Unité Reproduction et Développement des Plantes, F-69364 Lyon, France; INRA, UMR 879, Reproduction et Développement des Plantes, F-69364 Lyon, France; CNRS, UMR 5667, Reproduction et Développement des Plantes, F-69364 Lyon, France.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Chaignon
authors.affiliation: CNRS, UMR 9213, Institute of Plant Sciences Paris-Saclay, F-91405 Orsay, France.
authors.forename: Françoise
authors.initials: F
authors.lastname: Gilard
authors.affiliation: CNRS, UMR 9213, Institute of Plant Sciences Paris-Saclay, F-91405 Orsay, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Tcherkez
authors.affiliation: INRA, UMR 1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, Versailles, France; AgroParisTech, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, Versailles, France.
authors.forename: Johanne
authors.initials: J
authors.lastname: Thévenin
authors.affiliation: INRA, UMR 1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, Versailles, France; AgroParisTech, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, Versailles, France.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Dubreucq
authors.affiliation: Université de Lyon, Ecole Normale Supérieure de Lyon, Université Lyon 1, Unité Reproduction et Développement des Plantes, F-69364 Lyon, France; INRA, UMR 879, Reproduction et Développement des Plantes, F-69364 Lyon, France; CNRS, UMR 5667, Reproduction et Développement des Plantes, F-69364 Lyon, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Depège-Fargeix
authors.affiliation: Université de Lyon, Ecole Normale Supérieure de Lyon, Université Lyon 1, Unité Reproduction et Développement des Plantes, F-69364 Lyon, France; INRA, UMR 879, Reproduction et Développement des Plantes, F-69364 Lyon, France; CNRS, UMR 5667, Reproduction et Développement des Plantes, F-69364 Lyon, France. Electronic address: peter.rogowsky@ens-lyon.fr.
authors.forename: Peter M
authors.initials: PM
authors.lastname: Rogowsky
mesh_terms: D000595:Amino Acid Sequence; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D012639:Seeds / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D003313:Zea mays / Q000235:genetics* / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D014157:Transcription Factors
keywords: AFL network; Endosperm; Maize; Starch; Transcription factor