Figure legends
Figure 1: Maximum capacity of photosynthesis (a), measured at
20°C under CO2- and light-saturating conditions at the
end of each day of the acclimation period, for the Col-0 wild-type
(circles) and the fum2.1 mutant (triangles). Rates of net
photosynthesis at 20°C (b) and respiration (c) measured as
CO2 exchange in growth conditions on Col-0 andfum2.1 plants at 20°C (white) and at 4°C after the first day of
transfer (dashed) and after seven days of transfer (grey). Error bars
show standard mean error (n=3-5). Different labels on columns in (b) and
(c) indicate significantly different values (ANOVA, P<0.05)
Figure 2: Concentrations of starch (a), fumarate (b) and malate
(c) in leaves measured at the beginning (open symbols) and end (closed
symbols) of the photoperiod in Col-0 (circles) and fum2.1(triangles) plants. Error bars show standard mean error (n=5-7).
Figure 3: Pie charts summarizing the distribution of diurnally
fixed carbon, calculated from Figures 1-3 and data in Dyson et al.
(2016) for Col-0 (a-c) and fum2.1 (d-f) plants in control
conditions (a,d), on the first day of cold treatment (b,e) and after one
week of cold treatment (c,f). Beginning of day concentrations were
subtracted from end of day concentrations to estimate total diurnal
fluxes to different sinks. Values were normalized according to the
number of fixed carbons per metabolite. Export (and other) values were
calculated by subtracting all other values from the total diurnal carbon
capture via photosynthesis. Data for “sugar”, which include sucrose
and glucose, are included but are not visible on the scale of this
figure.
Figure 4: Total protein concentrations (a) as calculated from
Bradford assays. Different labels on columns indicate significantly
different values (ANOVA, P<0.05)Principal component analysis
(b) of the log2 scaled protein intensities in leaves of Col-0 (circles)
and fum2.1 (triangles) plants measured in control conditions
(open symbols) and after one week of cold treatment (closed symbols).
Hierarchical clustering and heat-maps (c) of the log2 scaled protein
values and their fold changes relative to Col-0 controls (indicated by
solid line), are shown for the two genotypes and conditions. Full
proteomic dataset is available in Supplementary Table S1.
Figure 5: Summary of the relative abundance of proteins for the
Benson-Calvin cycle enzymes of Col-0 (white bars) and fum2.1(grey bars) plants in control conditions (solid colours) and on Day 7 of
4°C treatment (hatched bars), as shown in the legend on the bottom left.
RuBP (ribulose bisphosphate), 3PG (3-phosphoglycerate), 1,3-BPG
(1,3-bisphosphoglycerate), GA3P (glyceraldehyde 3-phosphate), DHAP
(dihydroxy-acetone-phosphate), SDP (sedoheptulose-1,7-bisphosphate), FBP
(fructose-1,6-bisphosphate), F6P (fructose-6-phosphate), SDP
(sedoheptulose-1,7-bisphosphate), S7P (sedoheptulose-1-phosphate), Ru5P
(ribulose-5-phopshate), X5P (xylulose-5-phosphate). Data represent the
total summed signal for all unique detected peptides in each case,
normalised as described in the Methods. Error bars represent the
standard mean error, with different letters indicating significantly
different values
Figure 6: The two shortest feasible pathways for producing
fumarate in the cytosol, identified using a network analysis and flux
sampling (see Methods and Materials for more details). The two pathways
differ in the form of carbon exported from the chloroplast to the
cytosol compartments. RuBP (ribulose bisphosphate), PGA
(3-phosphoglyceric acid), DPGA (2,3-diphosphoglyverate), TP (triose
phosphate), 2PGA (2-phosphoglycerate), PEP (phosphoenolpyruvate
carboxylase), Pyr (Pyruvate), OAA (Oxaloacetate), Mal (Malate), Fum
(Fumarate).
Figure 7: Flux sampling results obtained from the Col-0 (black)
and fum2.1 (gray) models for the export of PGA (3-phosphoglyceric
acid ; a-d) and the export of TP (triose phosphate; e-h) from the
chloroplast. Models were constrained according to cold conditions (a,e),
to control conditions but with the rate of photosynthesis on the first
day of 4°C treatment (b,f) , to cold conditions on Day 7 of 4°C
treatment (c,g) and to control conditions with the production of NADPH
set to lowest feasible value (d,h). Each panel shows a frequency
diagram, representing the frequency with which each solution value was
achieved over repeated iterations of the modelling.