Benchmarking the impact different osmotic assays have on Arabidopsis biomass and gene expression.

A: Arabidopsis growth on plates under low-water agar, PEG, mannitol and NaCl treatments. B: Dry weight of Arabidopsis seedlings under different doses of each stress treatment (n = 12, * t-test adj. p < 0.01). C: Arabidopsis rosette dry weight after 3 to 5 days of withholding water (n = 9 - 11, * paired t-test p < 0.01). D - E: Number and intersect of differentially expressed genes (DEGs) in response to each osmotic stress treatment within root and shoot tissue (adj. p-value < 0.05). F: Heatmap displaying the top 500 most significantly differentially expressed genes in each osmotic stress assay in the root. G: Heatmap displaying the top 500 most significantly differentially expressed genes in response to drought stress in the root.

Comparative transcriptomic analysis reveals PEG, mannitol and NaCl downregulate drought inducible genes in the root.

A: Overlap analysis of genes found differentially expressed under drought treatment, compared to those under either PEG, mannitol, NaCl or low-water agar assays in both root and shoot (Fisher exact test adj. p < 0.05). B: Heatmap displaying genes differentially expressed under drought stress in root or shoot tissue compared to their expression under the highest dose of each osmotic stress assay. C - H: Expression patterns of drought marker genes under low, medium and high doses of each assay (where drought doses were Day 3, Day 4 and Day 5 respectively): HB12 (AT3G61890), GCL1 (AT5G65280), LEA7 (AT1G52690), RAB18 (AT1G43890), RD21 (AT1G47128), ANNAT4 (AT2G38750). I: Total rosette area of 20 Arabidopsis lines grown under either 100 % or 50 % low-water agar treatment.

Images of plants grown under different doses of each osmotic stress assay.

Arabidopsis growth on plates under low-water (LW) agar, PEG-6000, mannitol and salt (NaCl) treatments.

Gene expression profiles of canonical drought markers in shoot tissue.

A - F: Expression patterns of drought marker genes under low, medium and high doses of each assay (where drought doses were Day 3, Day 4 and Day 5 respectively). RD29B (AT5G52300), RD20 (AT2G33380), HB7 (AT2G46680), NCED3 (AT3G14440), P5CS1 (AT2G39800), ALDH10A8 (AT1G74920).

Comparative transcriptomic analysis reveals ABA induced differential expression is comparable to drought and low-water (LW) agar signaling

A: Intersect analysis of genes found differentially expressed under drought treatment, compared to those under either ABA, PEG, mannitol, NaCl or low-water agar assays in the root (Fisher exact test adj. p < 0.05). B: Heatmap displaying genes differentially expressed under drought stress in root tissue compared to their expression under the highest dose of each osmotic stress assay.

Associating low-water agar’s impact on shoot size with plant fitness.

Comparing the impact low-water agar treatment has on shoot size of 20 different Arabidopsis accessions to the change in their fitness found under drought conditions in the field, as reported in (25).