A Comparative Study of the Arabidopsis thaliana Guard-Cell Transcriptome and Its Modulation by Sucrose

Abstract

Microarray analysis was performed on RNA isolated from guard cells that were manually dissected from leaves of Arabidopsis. By pooling our data with those of two earlier studies on Arabidopsis guard cell protoplasts, we provide a robust view of the guard-cell transcriptome, which is rich in transcripts for transcription factors, signaling proteins, transporters, and carbohydrate-modifying enzymes. To test the hypothesis that photosynthesis-derived sugar signals guard cells to adjust stomatal opening, we determined the profile of genes expressed in guard cells from leaves that had been treated with sucrose. The results revealed that expression of 440 genes changed in guard cells in response to sucrose. Consistent with this hypothesis, these genes encoded cellular functions for photosynthesis and transport of sugars, water, amino acids, and ions. Plants of T-DNA insertion lines for 50 genes highly responsive to sucrose were examined for defects in guard cell function. Twelve 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, three are of particular interest, having shown effects in nearly every test of stomatal function without a change in stomatal density: TPS5 (At4g17770), a TRAF domain-containing protein (At1g65370), and a WD repeat–containing protein (At1g15440).

Functional Analysis of Cellulose and Xyloglucan in the Walls of Stomatal Guard Cells of Arabidopsis

“…FP-labeled CESA1, CESA3, and CESA6 particles show significant reductions in density in guard cells as plants mature (Supplemental Fig. S1), a finding that contrasts with previous guard cell-specific transcriptome data, in which primary wall CESAs were detected as being highly expressed in guard cells or guard cell protoplasts prepared from mature rosette leaves (Yang et al, 2008;Bates et al, 2012). A possible explanation for this inconsistency between CESA gene expression levels and our FP-CESA density data is that transcript abundance, protein abundance, protein stability, and protein localization are not always correlated with each other.…”

“…A possible explanation for this inconsistency between CESA gene expression levels and our FP-CESA density data is that transcript abundance, protein abundance, protein stability, and protein localization are not always correlated with each other. Alternatively, the transcriptome data might be confounded by changes in gene expression in response to stresses during sample preparation procedures, which involve cellulase treatment or freeze-drying (Yang et al, 2008;Bates et al, 2012). Another possibility is that CSCs containing the secondary wall-associated CESA isoform, CESA4, CESA7, or CESA8, generate additional cellulose to enable stomatal functions in mature plants, although CESA4, CESA7, or CESA8 has not been reported to be highly expressed in guard cells (Yang et al, 2008;Bates et al, 2012).…”

GOLDEN 2-LIKE transcription factors for chloroplast development affect ozone tolerance through the regulation of stomatal movement

“…Thermography monitoring also revealed that the leaf surface temperature of 35S:GLK1/2-SRDX plants was 1.5°C higher than that of WT and that the water loss of detached seedlings was 13% lower than WT ( We detected the expression of GLK1 and GLK2 in guard cells and mesophyll cells (Fig. S4), and our observations were consistent with the previously reported microarray data (29). To examine the possible mechanisms of the closed-stomata phenotype of 35S:GLK1/2-SRDX plants, we performed microarray experiments to find genes regulated by GLK1.…”

POLYGALACTURONASE INVOLVED IN EXPANSION3 Functions in Seedling Development, Rosette Growth, and Stomatal Dynamics in Arabidopsis thaliana

“…To identify pectin-modifying genes that are upregulated in guard cells, we mined stomatal transcriptome data sets (Bates et al, 2012;Hachez et al, 2011;Pandey et al, 2010;Yang et al, 2008). One gene, At1g48100, shows ;3-fold upregulation after 4 or 48 h of induction by FAMA (Hachez et al, 2011), a basic helix-loop-helix transcription factor that promotes guard cell identity (Ohashi-Ito and Bergmann, 2006), indicating that At1g48100 might function in guard cell differentiation.…”

“…Arabidopsis transcriptome data sets for developing and mature guard cells (Bates et al, 2012;Hachez et al, 2011;Pandey et al, 2010;Yang et al, 2008) contain many pectin-related genes, providing avenues for the identification of genes responsible for generating the unique structural and mechanical properties of guard cell walls. In this work, we identified one such gene, which we named POLYGALACTURONASE INVOLVED IN EXPANSION3 (PGX3).…”