Submitted to: PLoS One
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/15/2012
Publication Date: 11/26/2012
Citation: Bates, G.W., Rosenthal, D.M., Sun, J., Chattopadhyay, M., Peffer, E., Jones, A.M., Ort, D.R. 2012. A comparative study of the Arabidopsis thaliana guard-cell transcriptome and its modulation by sucrose. PLoS One. 7(11):e49641. Interpretive Summary: The guard cell is the most dynamic cell type in higher plants. Guard cells function to regulate the pore size of stomates and in so doing control the flux of carbon dioxide into leaves and loss of water from leaves. How this dynamic balance of carbon dioxide uptake to supply photosynthesis carbon dioxide with water loss is regulated is not well understood. In this study it is shown that the sugar produced by photosynthesis is itself an important signal that plays a central role in the regulation.
Technical Abstract: To test the hypothesis that photosynthesis-derived sugar signals guard cells to adjust stomatal opening, we determined the profile of genes expressed in isolated guard cells. The results revealed that expression of 289 genes increased in guard cells in response to sucrose. Consistent with the hypothesis, these genes encoded cellular functions for photosynthesis and transport of sugars, water, amino acids, and ions. We genetically deleted an informative set of genes to determine whether their absence impaired guard-cell function. Thirteen genes not previously known to function in guard cells were shown to be important in leaf conductance, water-use efficiency, and/or stomate development. Of these, were LOX1 (At1g55020), a flavin monooxygenase (At1g62450), two putative protein kinases (At5g39030 and At4g38470), a WD repeat-containing protein (At1g15440), and trehalose phosphate synthase 5 (TPS5, At4g17770).