Differential Expression Control and Polarized Distribution of Plasma Membrane-Resident SYP1 SNAREs in Arabidopsis thaliana

Abstract

Membrane trafficking to the plasma membrane (PM) is a highly organized process which enables plant cells to build up their bodies. SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) genes, which encode the proteins involved in membrane trafficking, are much more abundant in the Arabidopsis genome than in that of any other eukaryote. We have previously shown that a large number of SNARE molecules in the Arabidopsis cell are localized predominantly on the PM. In the present study, in order to elucidate the physiological function of each PM-localized SNARE, we analyzed the spatiotemporal expression profiling of nine SYP1s that are resident in the PM of Arabidopsis, and used the information thus acquired to generate transgenic Arabidopsis plants expressing green fluorescent protein-fused Qa-SNAREs under control of their authentic promoters. Among the nine SYP1s, only SYP132 is expressed ubiquitously in all tissues throughout plant development. The expression patterns of the other SYP1s, in contrast, are tissue specific, and all different from one another. A particularly noteworthy example is SYP123, which is predominantly expressed in root hair cells during root development, and shows a focal accumulation pattern at the tip region of root hairs. These results suggest that SYP132 is involved in constitutive membrane trafficking to the PM throughout plant development, while the other SYP1s are involved in membrane trafficking events such as root formation or tip growth of root hair, with some redundancy.

Requirement of Vesicle-Associated Membrane Protein 721 and 722 for Sustained Growth during Immune Responses in Arabidopsis

“…The very low luciferase activity seen in protoplasts co-expressing Nluc-SYP132 and the Cluc-VAMP723 (Fig. 3C) suggests that PM-localized SYP132 predominantly interacts with PM-destined VAMP721/722 (Enami et al, 2009). …”

“…Since PEN1 in Arabidopsis appears to specifically limit the entry of non-adapted powdery mildew fungi into epidermal cells (Collins et al, 2003;Kwon et al, 2008c), NbSYP132 has been proposed to participate in SNARE complex-driven exocytosis required for resistance to bacteria. SYP132 is localized to the PM in Arabidopsis leaves and roots (Enami et al, 2009). Interestingly, the isolation of homozygous syp132 Arabidopsis plants failed and the NbSYT132 silencing resulted in severely growth-defective tobacco plants (Enami et al, 2009;Kalde et al, 2007), indicative of an additional SYP132 function in plant growth and development.…”

“…SYP132 is localized to the PM in Arabidopsis leaves and roots (Enami et al, 2009). Interestingly, the isolation of homozygous syp132 Arabidopsis plants failed and the NbSYT132 silencing resulted in severely growth-defective tobacco plants (Enami et al, 2009;Kalde et al, 2007), indicative of an additional SYP132 function in plant growth and development. We thus tested whether Arabidopsis SYP132 can form a ternary SNARE complex with SNAP33 and VAMP721/722 in vitro.…”

Vesicle Dynamics during Plant Cell Cytokinesis Reveals Distinct Developmental Phases

“…We thank Dr. Hugo Zhang and Dr. Masa H. Sato for providing p35s::ARA7-YFP and pSYP111::GFP-SYP111 (Enami et al, 2009) GFP-KN plasmids, respectively, Dr. Andreas Nebenführ for the G-RK plasmid (Nelson et al, 2007), and Dr. Richard Cyr for GFP-MBD (from MAP4; Granger and Cyr, 2000). LITERATURE CITED…”

Binding of SEC11 Indicates Its Role in SNARE Recycling after Vesicle Fusion and Identifies Two Pathways for Vesicular Traffic to the Plasma Membrane

“…Single mutations of these Qa-SNAREs have little effect on plant growth under many conditions, and reduced growth is normally evident only in the syp121/syp122 double mutant (Assaad et al, 2004;Zhang et al, 2007). Both SYP121 and SYP122 are expressed throughout the development of the plant and in most, if not all, tissues (Uemura et al, 2004;Enami et al, 2009). The Qa-SNAREs also share the cognate partner proteins SNAP33, VAMP721, and VAMP722 Rehman et al, 2008;Karnik et al, 2013b), indicating substantial mechanistic overlaps in driving vesicle fusion.…”