Arabidopsis F-box protein regulates tapetum degeneration and pollen maturation during anther development

• Published in: Planta 2010-07, Vol.232 (2), p.353-366
• Main Authors: Kim, Ok-Kyoung, Jung, Jae-Hoon, Park, Chung-Mo
• Format: Article
• Language: English
• Subjects: Agriculture; Anther dehiscence; Anthers; Arabidopsis; Arabidopsis - genetics; Arabidopsis - growth & development; Arabidopsis - metabolism; Arabidopsis - ultrastructure; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; ASK1; Biological and medical sciences; Biomedical and Life Sciences; Biosynthesis; Dehiscence; Developmental biology; Developmental stages; Ecology; Epidermis; F box proteins; F-Box Motifs - genetics; F-Box Motifs - physiology; F-box protein; Fertility; Flowers - genetics; Flowers - growth & development; Flowers - metabolism; Flowers - ultrastructure; Forestry; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Plant - genetics; Gene Expression Regulation, Plant - physiology; Genes; Life Sciences; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; Microspores; Original Article; Plant Sciences; Plants; Plants, Genetically Modified - genetics; Plants, Genetically Modified - growth & development; Plants, Genetically Modified - metabolism; Plants, Genetically Modified - ultrastructure; Pollen; Pollen - genetics; Pollen - growth & development; Pollen - metabolism; Pollen - ultrastructure; Protein Binding; Proteins; Tapetum degeneration; Two-Hybrid System Techniques
• ISSN: 0032-0935; 1432-2048
• DOI: 10.1007/s00425-010-1178-x

The Arabidopsis anther has a bilateral symmetry with four lobes, each consisting of four distinct layers of somatic cells from the outer to inner side: epidermis, endothecium, middle layer and tapetum. The tapetum is a layer of cells comprising the inner surface of the pollen wall. It plays an important role in anther development by providing enzymes, materials and nutrients required for pollen maturation. Genes and molecular mechanisms underlying tapetum formation and pollen wall biosynthesis have been studied in Arabidopsis. However, tapetum degeneration and anther dehiscence have not been well characterized at the molecular level. Here, we report that an Arabidopsis gene, designated reduced male fertility (RMF), regulates degeneration of tapetum and middle layer during anther development. The Arabidopsis dominant mutant rmf-1D overexpressing the RMF gene exhibited pleiotropic phenotypes, including dwarfed growth with small, dark-green leaves and low male fertility. Tapetum development and subsequent degeneration were impaired in the mutant. Accordingly, pollen maturation was disturbed, reducing the male fertility. In contrast, tapetum degeneration was somewhat accelerated in the RMF RNAi plants. The RMF gene was expressed predominantly in the anther, particularly in the pollen grains. Notably, the RMF protein contains an F-box motif and is localized to the nucleus. It physically interacts with the Arabidopsis-Skp1-like1 protein via the F-box motif. These observations indicate that the RMF gene encodes an F-box protein functioning in tapetum degeneration during anther development.