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 wild-type Col-0
(circles) and the fum2.2 mutant (triangles). Rates of net
photosynthesis (b) and respiration (c) measured as CO2exchange in growth conditions on Col-0 and fum2.2 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 fum2.2(triangles) plants. Error bars show standard mean error (n=5-7).
Figure 3: Distribution of diurnally fixed carbon, calculated
from Figures 1-3 and data in Dyson et al. (2016) for Col-0 (a,c) andfum2.2 (b,f) plants in control conditions, on the first day of
cold treatment (D0) and after one week of cold treatment (D7).
Beginning-of-day concentrations were subtracted from end-of-day
concentrations to estimate total diurnal fluxes to different sinks.
Measured carbon sinks are fumarate (orange), malate (green), diurnal
respiration (blue) and starch (purple). Export (and other) values (c,d)
were calculated by subtracting all other values from the total diurnal
carbon capture via photosynthesis. Data for “sugar”, which include
sucrose and glucose retained in the leaf, are included in the analysis
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 fum2.2 (triangles) plants measured .in control conditions
(open symbols) and after one week of cold treatment (closed symbols).
Hierarchical clustering and heat-map (c) of the log2 scaled protein
values. Fold changes for Cluster 1 (d), 2 (e), 3 (f) and 4 (g), relative
to Col-0 controls, are shown for the two genotypes and conditions. Full
proteomic dataset is available in Table S1.
Figure 5: Summary of the relative abundance of proteins for the
Benson-Calvin cycle enzymes of Col-0 (white bars) and fum2.2(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. 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 Materials and Methods 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 fum2.2 (red) 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.
Figure 8: Seed yield in plants of wild type Col-0 andfum2.2 grown for 8 weeks at 20oC and then
either maintained at 20oC for a further 7 days (white
bars), or transferred to 4oC for the same time (grey
bars), before being transferred to a 16h day, to induce flowering. For
each plant, the number of seeds per silique was counted for 10 siliques
per plant (a) and the number of siliques counted on 6 plants (b). Total
seed yield per plant was estimated as the product of these numbers (c).
Error bars shown represent the standard error of the mean. Different
letters on the bars indicate significantly different values (ANOVA,
P<0.05).