title: SPL8 Acts Together with the Brassinosteroid-Signaling Component BIM1 in Controlling Arabidopsis thaliana Male Fertility.
abstract: The non-miR156 targeted SBP-box gene SQUAMOSA PROMOTER BINDING PROTEIN-LIKE 8 (SPL8), plays an important role in Arabidopsis anther development, where its loss-of-function results in a semi-sterile phenotype. Fully male-sterile plants are obtained when a spl8 loss-of-function mutation is introduced into a 35S:MIR156 genetic background, thereby revealing functional redundancy between SPL8 and miR156-targeted SBP-box genes. Here, we show that BIM1, a gene encoding a bHLH protein involved in brassinosteroid signaling and embryonic patterning, functions redundantly with SPL8 in its requirement for male fertility. Although bim1 single mutants displayed a mild fertility problem due to shortened filaments in some flowers, mutation of BIM1 significantly enhanced the semi-sterile phenotype of the spl8 mutant. Expression of both SPL8 and BIM1 was detected in overlapping expression domains during early anther developmental stages. Our data suggest that in regulating anther development, SPL8 and BIM1 function cooperatively in a common complex or in synergistic pathways. Phylogenetic analysis supports the idea of an evolutionary conserved function for both genes in angiosperm anther development.
authors.affiliation: Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Cologne 50829, Germany. xing@mpipz.mpg.de.
authors.forename: Shuping
authors.initials: S
authors.lastname: Xing
authors.affiliation: Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Cologne 50829, Germany.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Quodt
authors.affiliation: Institute of Developmental Biology, Cologne Biocenter, University of Cologne, Cologne 50674, Germany. john.chandler@uni-koeln.de.
authors.forename: John
authors.initials: J
authors.lastname: Chandler
authors.affiliation: Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Cologne 50829, Germany. hoehmann@mpipz.mpg.de.
authors.forename: Susanne
authors.initials: S
authors.lastname: Höhmann
authors.affiliation: Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Cologne 50829, Germany. berndtge@mpipz.mpg.de.
authors.forename: Rita
authors.initials: R
authors.lastname: Berndtgen
authors.affiliation: Department of Comparative Development and Genetics, Max Planck Institute for Plant Breeding Research, Cologne 50829, Germany. huijser@mpipz.mpg.de.
authors.forename: Peter
authors.initials: P
authors.lastname: Huijser
keywords: Arabidopsis thaliana; BIM1; SPL8; anther development; brassinosteroid signaling; male fertility