Fig. 8

Characterization of central metabolic model for controlling carbon and FA flux for high oil synthesis in L. glauca fruits. The constructed metabolism regulatory network of carbon flux allocation for high-quality oil production in L. glauca fruits represents the most relevant pathways (glycolysis, PPP, acetyl-CoA formation, de novo FA synthesis and its elongation, plastidic FA export and desaturation, and TAG assembly) and includes all identified regulators (enzymes, transcription factors and transporters) with strong correlation with carbon flux partitioning into FA synthesis and TAG assembly, all of which are characterized by the comparative analysis of cross-accessions association of gene transcription level (qRT-PCR detection) with oil accumulative amount in fruits across all accessions, together with our recent transcriptome sequencing data from developing L. glauca fruits. All enzymes presented here are shown in blue. The values generated from qRT-PCR indicate relative transcript levels in the fruits from high-oil accession LG06 (green values) and low-oil accession LG01 (red values), all of which are calculated by the standardized set of expression level for inner reference gene to 1.00. The background color distinguishes different subcellular locations or pathways for FA and TAG synthesis as follows: gray and bright blue signify cytosolic and plastidic glycolysis, respectively; light red refers to plastidic PPP; light green signifies de novo FA synthesis; light blue signifies TCA cycle in mitochondria; yellow signifies TAG assembly in ER. Black arrows represent all reactions for major carbon allocation into FA synthesis and TAG assembly, and brown arrows represent minor carbon allocation for FA and TAG synthesis. purple arrows represent metabolite transport across intracellular membrane by specific transporters. Abbreviations for main enzymes, metabolites and transporters are as follows: ACC, acetyl-CoA carboxylase; BASS, pyruvate (PYR) carrier; DGAT, diacylglycerol (DAG) acyltransferase; EAR, enoyl-ACP reductase; ER, endoplasmic reticulum; FAD, FA desaturase; FATA/B, fatty acyl-ACP thioesterase A/B; FAX, FA exporter; G6PDH, glucose-6-phosphate (G6P) dehydrogenase; GPAT, acyl-CoA:G3P acyltransferase; GPI, G6P isomerase; GPT, G6P transporter; HAD, hydroxyacyl-ACP dehydrase; HXK, hexokinase; INV, invertase; KAR, ketoacyl-ACP reductase; KAS, 3-ketoacyl ACP synthase; LACS, long-chain acyl-CoA synthase; LPAAT, lysoPA acyltransferase; LPCAT, lysoPC acyltransferases; 6PGDH, 6-phosphogluconate dehydrogenase; PAP, phosphatidic acid (PA) phosphohydrolases; PC, phosphatidylcholine; PDAT, phospholipid:DAG acyltransferase; PDC, pyruvate (PYR) dehydrogenase complex; PK, PYR kinase; PPP, pentose phosphate pathway; PPT, PEP transporter; TAG, triacylglycerol; TPT, triose phosphate transporters