AtTMEM18 plays important roles in pollen tube and vegetative growth in Arabidopsis

• Published in: Journal of integrative plant biology 2016-07, Vol.58 (7), p.679-692
• Main Authors: Dou, Xiao-Ying, Yang, Ke-Zhen, Ma, Zhao-Xia, Chen, Li-Qun, Zhang, Xue-Qin, Bai, Jin-Rong, Ye, De
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Arabidopsis; Arabidopsis - genetics; Arabidopsis - growth & development; Arabidopsis - metabolism; Arabidopsis Proteins - chemistry; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Cell Nucleus - metabolism; Cell Proliferation; Gene Expression Regulation, Plant; Genetic Complementation Test; Germination; Green Fluorescent Proteins - metabolism; male gametophyte; Membrane Proteins - chemistry; Membrane Proteins - genetics; Membrane Proteins - metabolism; Mutation - genetics; Oryza - genetics; Phenotype; plant; Plants, Genetically Modified; pollen; Pollen Tube - growth & development; Pollen Tube - metabolism; Subcellular Fractions - metabolism; TMEM18; transmembrane protein
• ISSN: 1672-9072; 1744-7909
• DOI: 10.1111/jipb.12459

In flowering plants, pollen tube growth is essential for delivery of male gametes into the female gametophyte or embryo sac for double fertilization. Although many genes have been identified as being involved in the process, the molecular mechanisms of pollen tube growth remains poorly understood. In this study, we identified that the Arabidopsis Transmembrane Protein 18 (AtTMEM18) gene played important roles in pollen tube growth. The AtTMEM18 shares a high similarity with the Transmembrane 18 proteins (TMEM18s) that are conserved in most eukaryotes and may play important roles in obesity in humans. Mutation in the AtTMEM18 by a Ds insertion caused abnormal callose deposition in the pollen grains and had a significant impact on pollen germination and pollen tube growth. AtTMEM18 is expressed in pollen grains, pollen tubes, root tips and other vegetative tissues. The pollen‐rescued assays showed that the mutation in AtTMEM18 also caused defects in roots, stems, leaves and transmitting tracts. AtTMEM18‐GFP was located around the nuclei. Genetic assays demonstrated that the localization of AtTMEM18 around the nuclei in the generative cells of pollen grains was essential for the male fertility. Furthermore, expression of the rice TMEM18‐homologous protein (OsTMEM18) driven by LAT52 promoter could recover the fertility of the Arabidopsis attmem18 mutant. These results suggested that the TMEM18 is important for plant growth in Arabidopsis. The Transmembrane 18 proteins (TMEM18s) are conserved in most eukaryotes and may be related to obesity in humans. This study shows that Arabidopsis TMEM18 (AtTMEM18) plays important roles in plant growth. Mutation in AtTMEM18 affected callose deposition and caused defects in pollen tube and other plant tissues.