The use of quantitative imaging to investigate regulators of membrane trafficking in Arabidopsis stomatal closure

• DOI: 10.1111/tra.12625
• Publication Date: 2018-11-17T05:05:48Z
• Authors: Gildas Bourdais; Deirdre H. McLachlan; Lydia M. Rickett; Ji Zhou; Agnieszka Siwoszek; Heidrun Häweker; Matthew Hartley; Hannah Kuhn; Richard J. Morris; Dan MacLean; Silke Robatzek
• Keywords: 0301 basic medicine; 570; flg22; Arabidopsis; Endosomes; chitin; 03 medical and health sciences; Osmotic Pressure; endosome; ARA7; 580; 0303 health sciences; calcium; Arabidopsis Proteins; Cell Membrane; ROS; immunity; Protein Transport; ABA; rab GTP-Binding Proteins; Plant Stomata; Single-Cell Analysis; FLS2; SNARE Proteins; Protein Kinases; ARA6

Expansion of gene families facilitates robustness and evolvability of biological processes but impedes functional genetic dissection of signalling pathways. To address this, quantitative analysis of single cell responses can help characterize the redundancy within gene families. We developed high‐throughput quantitative imaging of stomatal closure, a response of plant guard cells, and performed a reverse genetic screen in a group of Arabidopsis mutants to five stimuli. Focussing on the intersection between guard cell signalling and the endomembrane system, we identified eight clusters based on the mutant stomatal responses. Mutants generally affected in stomatal closure were mostly in genes encoding SNARE and SCAMP membrane regulators. By contrast, mutants in RAB5 GTPase genes played specific roles in stomatal closure to microbial but not drought stress. Together with timed quantitative imaging of endosomes revealing sequential patterns in FLS2 trafficking, our imaging pipeline can resolve non‐redundant functions of the RAB5 GTPase gene family. Finally, we provide a valuable image‐based tool to dissect guard cell responses and outline a genetic framework of stomatal closure.