Figure 1.
Pathways of triacylglycerol biosynthesis.
Reactions in the formation of hydroxylated TAGs via the acyl-CoA dependent (solid arrows) and independent (dashed arrows) pathways are shown. Lipid substrates are abbreviated: 18:1, oleic acid; 18:1-OH, ricinoleic acid; LPC, lysophosphatidylcholine; DAG, diacylglycerol. Enzyme abbreviations are: Δ12-OHase, oleate-12-hydroxylase; LPCAT, 1-acylglycerol-3-phosphocholine acyltransferase; PL-A2, phospholipase A2; LACS, long chain acyl-CoA synthetase; GPAT, glycerol-3-phosphate acyltransferase; LPAT, lysophosphatidic acid acyltransferase; PAP, phosphatidic acid phosphatase; DGAT, diacylglycerol acyltransferase; CPT, CDP-choline:diacylglycerol cholinephosphotransferase; PL-C, phospholipase C; PDAT, phosphatidylcholine diacylglycerol acyltransferase.
Figure 2.
Acyl-CoA analysis of developing castor endosperm.
A chromatogram of fluorescent acyl-CoA derivatives from developing castor endosperm stage III is shown - dark trace. Results from analysis of synthesised 18:1-OH-CoA (green line) and other acyl-CoA standards (red trace) are superimposed to confirm the indicated peak identities in the endosperm sample.
Table 1.
Acyl-CoA levels in developing castor endosperm.
Figure 3.
TLC analysis of neutral lipids from castor developing male flowers and pollen.
Lipid extracts were applied to a silica TLC plate which was developed with hexane/diethyl ether/acetic acid (70∶30∶1) before iodine-staining. The position of lipid standard components (lane N) and proposed nature of resolved sample lipids are shown. Lipid X and proposed sterol esters were purified for further analysis.
Table 2.
Fatty acid analysis of castor tissues and purified lipid X.
Figure 4.
MS analysis of purified neutral lipids from pollen.
Purified neutral lipids from pollen were analysed by TLC and used for electrospray MS analysis in the presence of lithium (panel A). Ions between 830 and 900 amu in the lipid X fraction (highlighted in red and Panel B) were selected for fragmentation and the diagnostic fragments produced, such as those in Panel C from the 858 mass ion, allowed determination of fatty acid composition of proposed TAG species (Panel D).
Table 3.
Candidate genes that may be important in tri-ricinolein synthesis based on RNA-Seq data.