Fig. 6

Mapping genes enriched in H4ac to secondary metabolism nodes. Mapping details for the A α -linolenic acid metabolism (α-LA) and B phenylpropanoid (PP) biosynthesis showing that MeJA caused the enrichment of the activating marker, H4ac, on specific genes for α-LA biosynthetic enzymes in a HDA6-dependent or HDA6-independent manner. In the first category were hydroperoxide lyase (HPL1; AT4G15440) and acetyl-CoA acyltransferase 1/peroxisomal 3-ketoacyl-CoA thiolase (PKT4; AT1G04710) (WT +MeJA). The H4ac enrichment of the phospholipase A1 (DAD1, AT2G44810); lipoxygenases LOX2 (AT3G45140) LOX3 (AT1G17420), LOX4 (AT1G72520), LOX6 (AT1G67560), allene oxide cyclases AOC1/2/3 (AT3G25760, AT3G25770, AT3G25780), and 12-oxophytodienoic acid reductase OPR2 (AT1G76690) was instead HDA6 independent. For PP, the activating marker was enriched by MeJA in WT, but not in an axe1-5 background, namely on hydroxycinnamoyl-CoA shikimate/quinate hydroxycinnamoyl transferase (HCT, AT5G48930) and CYP98A3 (AT2G40890). The H4ac enrichment of most enzymes in the pathway was instead axe1-5 independent. The following genes were specifically enriched: the ferulate-5-hydroxylase FAH1 (AT4G36220), the UDP-Glycosyltransferase UGT84A2 (AT3G21560); several 4-coumarate:CoA ligases (4CL1/2/3, AT1G51680, AT3G21240, AT1G65060); a member of the S-adenosyl-L-methionine-dependent methyltransferases superfamily (AT4G26220); FAD-binding Berberine family protein member, cinnamyl-alcohol dehydrogenases (AT1G30760) and ELI3-1 (cinnamyl-alcohol dehydrogenase 7 (AT4G37980). Several members of the peroxidase superfamily linked to phenylpropanoid/monolignols biosynthesis and stress responses [89, 90] were also enriched: PR9 (AT1G05240), PRX2 (AT1G05250), RCI3 (RARE COLD INDUCIBLE GENE 3; cationic peroxidase; AT1G05260) and several uncharacterized ones (AT2G18150, AT5G14130, AT5G17820, AT5G58390 and AT5G58400). Colours as described in the International Union of Biochemistry and Molecular Biology (IUBMB) enzyme nomenclature shown