Exocyst subunit SEC3A marks the germination site and is essential for pollen germination in Arabidopsis thaliana

• Published in: Scientific reports 2017-01, Vol.7 (1), p.40279-40279, Article 40279
• Main Authors: Li, Yan, Tan, Xiaoyun, Wang, Mengru, Li, Bingxuan, Zhao, Yanxue, Wu, Chengyun, Rui, Qingchen, Wang, Junxia, Liu, Zhongyuan, Bao, Yiqun
• Format: Article
• Language: English
• Subjects: 13/44; 14/19; 45/22; 631/449/2653/2659; 631/449/448/2024; Arabidopsis - cytology; Arabidopsis - genetics; Arabidopsis - growth & development; Arabidopsis - metabolism; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Cell Wall - metabolism; Cellulose; Deoxyribonucleic acid; DNA; Gene Expression Regulation, Plant; Genetic Complementation Test; Genotype; Germination; Green Fluorescent Proteins - metabolism; Humanities and Social Sciences; Localization; multidisciplinary; Mutation - genetics; Nucleotide sequence; Pectin; Phenotype; Phosphatidylinositol 4,5-diphosphate; Phosphatidylinositol 4,5-Diphosphate - metabolism; Plants, Genetically Modified; Pollen; Pollen - cytology; Pollen - growth & development; Pollen - metabolism; Pollen tubes; Protein Subunits - metabolism; Science; Science (multidisciplinary); T-DNA; Transgenes; Vesicular Transport Proteins - genetics; Vesicular Transport Proteins - metabolism
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep40279

Arabidopsis exocyst subunit SEC3A has been reported to participate in embryo development. Here we report that SEC3A is involved during pollen germination. A T-DNA insertion in SEC3A leads to an absolute, male-specific transmission defect that can be complemented by the expression of SEC3A coding sequence from the LAT52 promoter or SEC3A genomic DNA. No obvious abnormalities in the microgametogenesis are observed in the sec3a/SEC3A mutant, however, in vitro and in vivo pollen germination are defective. Further studies reveal that the callose, pectin, and cellulose are apparently not deposited at the germination site during pollen germination. SEC3A is expressed ubiquitously, including in pollen grains and pollen tubes. Notably, SEC3A-GFP fusion proteins are specifically recruited to the future pollen germination site. This particular localization pattern is independent of phosphatidylinositol 4,5-bisphosphate (PI-4,5P 2 ), although SEC3-HIS fusion proteins are able to bind to several phosphoinositols in vitro . These results suggest that SEC3A plays an important role in the establishment of the polar site for pollen germination.