Arabidopsis Synaptotagmin 2 Participates in Pollen Germination and Tube Growth and Is Delivered to Plasma Membrane via Conventional Secretion

• Published in: Molecular plant Vol. 8; no. 12; pp. 1737 - 1750
• Main Author: Hui Wang Shengcheng Han Wei Siao Chunqing Song Yun Xiang Xiaorong Wu Pengyu Cheng Hongjuan Li JAn Jasik Karol Micieta JAn Turna Boris Voigtt Frantisek Baluska Jin Liu Yingdian Wang Heping Zhao
• Format: Journal Article
• Language: English
• Published: England Elsevier Inc 07.12.2015
• Subjects: Arabidopsis - genetics; Arabidopsis - growth & development; Arabidopsis - metabolism; Arabidopsis Proteins - chemistry; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; C2 domains; calcium-dependent phospholipid binding; Cell Membrane - genetics; Cell Membrane - metabolism; conventional secretion; Gene Expression Regulation, Plant; Germination; Golgi Apparatus - genetics; Golgi Apparatus - metabolism; Pollen - genetics; Pollen - growth & development; Pollen - metabolism; pollen germination; Pollen Tube - genetics; Pollen Tube - growth & development; Pollen Tube - metabolism; Protein Structure, Tertiary; Protein Transport; Synaptotagmin II - chemistry; Synaptotagmin II - genetics; Synaptotagmin II - metabolism; synaptotagmins; 下线; 服务; 迁移; pollen germination; synaptotagmins; C2 domains; calcium-dependent phospholipid binding; conventional secretion
• ISSN: 1674-2052; 1752-9867
• DOI: 10.1016/j.molp.2015.09.003

Arabidopsis synaptotagmin 2 （SYT2） has been reported to participate in an unconventional secretory pathway in somatic cells. Our results showed that SYT2 was expressed mainly in the pollen ofArabidopsis thaliana. The pollen of syt2 T-DNA and RNA interference mutant lines exhibited reduced total germination and impeded pollen tube growth. Analysis of the expression of SYT2-GFP fusion protein in the pollen tube indicates that SYT2 was localized to distinct, patchy compartments but could co-localize with the Golgi markers, BODIPY TR C5 ceramide and GmManl-mCherry. However, SYT2-DsRed-E5 was localized to the plasma membrane in Arabidopsis suspension cells, in addition to the Golgi apparatus. The localization of SYT2 at the plasma membrane was further supported by immunofluorescence staining in pollen tubes. Moreover, brefeldin A treatment inhibited the transport of SYT2 to the plasma membrane and caused SYT2 to aggregate and form enlarged compartments. Truncation of the SYT2-C2AB domains also resulted in retention of SYT2 in the Golgi apparatus. An in vitro phospholipid-binding assay showed that SYT2-C2AB domains bind to the phospholipid membrane in a calcium-dependent manner. Take together, our results indicated that SYT2 was required for pollen germination and pollen tube growth, and was involved in conventional exocytosis.