Effect of temperature on the transcript abundance of the TAG pathway genes.

<p>Relative transcript abundance changes for the transcripts of the lipid biosynthesis pathway are provided in (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0127562#pone.0127562.s020" target="_blank">S7A Table</a>). Compounds include: G-3-P, glycerol-3-phosphate; Lyso-PA, lyso-phosphatidic acid; PA, phosphatidic acid; PG, phosphatidylglycerol, SQDG, sulfoquinovosyldiacylglycerol; MGDG, monogalactosyldiacylglycerol, DGDG, digalactosyldiacylglycel, DAG: diacylglycerol, TAG, triacylglycerol. Enzymes include: GPAT, glycerol-3-P acyltransferase; LPAT, lysophosphatidic acid acyltransferase; PAH, phosphatidate phosphatase; DGAT and DGTT, diacylglycerol acyltransferase; PCT, CDP-diacylglycerol synthase; PGP, phosphatidylglycerolphosphate synthase; SQD1, UDP-sulfoquinovose synthase; SGD2, sulfolipid synthase; MGD1, monogalactosyldiacylglycerol synthase; DGD1, digalactosyldiacyglycerol synthase; PGD1, plastid galactoglycerolipid degradation1; GGGT, galactolipid:galactolipid galactosyltransferase; PDAT1, phospholipid:diacylglycerol acyltransferase; MLDP, major lipid droplet protein; Kcs, β-ketoacyl-CoA synthase; CHAD, 3-hydroxyacyl-CoA dehydrogenase; TER, Trans-2-enoyl-CoA reductase; PCH, Palmitoyl-CoA hydrolase; FAD5, MGDG specific palmitate Δ-7 desaturase; FAD6, ω-6 fatty acid desaturase; FAD7, ω -3 fatty acid desaturase; LCIII, class 3 lipase, FAP, class 3 lipase, LIP, lipase; TAGL, triacylglycerol lipase.</p

TAG content increases under LL (A) and saturated FAs accumulate at 35°C in TAG (B).

<p><i>D</i>. <i>viridis</i> cultures were grown either under LD (dashed lines) or LL (solid lines). All cultures were grown at 25°C for the first 24 hours and then either remained at 25°C (blue lines) or the temperature in the growth chamber was raised to 35°C (red lines). The temperature shift is indicated by the black arrow. Total TAG content was calculated as the sum of the fatty acids from the TAG fraction. Total TAG content was normalized to 1 million cells. The error bars represent the standard deviation from three independent biological replicates. Statistical significance was assessed by unpaired, two-tailed, Student’s <i>t</i>-test. The values with the same letters are not significantly different at 54 hrs (p<0.05).</p

Cell cycle regulated genes show diurnal regulation under LD, but constant transcript levels in LL.

<p>Lines represent the changes in transcript abundance (RPKM) for each of the genes. Genes are: H2A, histone H2A; CYCA, A-type cyclin; CYCB1, B-type cyclin 1; CYCB2, B-type cyclin 2; cyclin dependent kinase B.</p

Changes in fatty acid composition of the TAG fraction.

<p>The error bars represent the standard deviation from three independent biological replicates. Statistical significance was assessed by unpaired, two-tailed, Student’s <i>t</i>-test. The values with the same letters are not significantly different at 54 hrs (p<0.05).</p

Categories enriched in differentially expressed transcripts under LL or high temperature.

<p>For each one of the two factors, the categories enriched are presented. The expected column presents the number of transcripts that were expected in a specific category based on the transcripts per GO and the number of differentially expressed transcripts. The count column presents the actual number of transcripts differentially expressed in that category. The third column shows the overrepresentation of a category calculated as the ratio of count/expected hits.</p><p>Categories enriched in differentially expressed transcripts under LL or high temperature.</p

Total chlorophyll (A) and soluble protein (B) content in <i>D</i>. <i>viridis</i> in response to light duration and temperature.

<p>While chlorophyll content increases in response to elevated temperature, soluble protein content in those cells decreases. <i>D</i>. <i>viridis</i> cultures were grown either under LD (dashed lines) or LL (solid lines). All cultures were grown at 25°C for the first 24 hours and then either remained at 25°C (blue lines) or the temperature in the growth chamber was raised to 35°C (red lines). Temperature shift is indicated by the black arrow. Total chlorophyll content, soluble protein and cell counts were measured in three biological replicates with three technical replicates each. The data were normalized to 1 million cells. The error bars represent the standard deviation. Statistical significance was assessed by unpaired, two-tailed, Student’s <i>t</i>-test. The values with the same letters are not significantly different at 54 hrs (p<0.05).</p

Major polar lipid classes responds to photoperiod and temperature changes.

<p>The cellular content of the major polar lipid classes DGDG (grey bars), MGDG (black bars) and PL (striped bars) responded to changes in temperature and light duration. The error bars represent the standard deviation from three independent biological replicates. Statistical significance was assessed by unpaired, two-tailed, Student’s <i>t</i>-test. The values with the same letters are not significantly different at 54 hrs (p<0.05).</p

Total starch in <i>D</i>. <i>viridis</i> cells in response to light duration and temperature.

<p><i>D</i>. <i>viridis</i> cultures were grown either under LD (dashed lines) or LL (solid lines). All cultures were grown at 25°C for the first 24 hours and then either remained at 25°C (blue lines) or the temperature in the growth chamber was raised to 35°C (red lines). The temperature shift is indicated by the black arrow. The data were normalized to 1 million cells. The error bars represent the standard deviation from three independent biological replicates. Statistical significance was assessed by unpaired, two-tailed, Student’s <i>t</i>-test. The values with the same letters are not significantly different at 54 hrs (p<0.05).</p

Cell division rate and cell size increases under LL versus LD cycles.

<p><i>D</i>. <i>viridis</i> cultures were grown either under LD (dashed lines) or LL (solid lines) at 25°C for the first 24 hours and then either remained at 25°C (blue lines) or the temperature was raised to 35°C (red lines). The temperature shift occurred after 24hrs (black arrow). Cell counts (A) and maximal cell diameters (B) were measured in three biological replicates with three technical replicates each. The error bars represent the standard deviation. Statistical significance was assessed by unpaired, two-tailed, Student’s <i>t</i>-test. The values with the same letters are not significantly different at 54 hrs (p<0.05).</p

Numbers of transcripts responding to changes in light duration and/or temperature at 30, 40 and 54 hours.

<p>The diagrams represent the number of transcripts differentially expressed either only in response to continuous light compared to light:dark cycles at 25°C (25°C-LL/LD) or only in response to increased temperature under continuous light (LL-35°C/25°C).</p