Schematic view of lignin and lignan biosynthetic and polymerization genes up- and down-regulated in flax inner and outer stem tissues. CAD, Cinnamyl alcohol dehydrogenase; CCoAOMT, caffeoyl-CoA O-methyltransferase; CCR, cinnamoyl-CoA reductase; C3H, p-coumaroyl shikimate 3′-hydroxylase; C4H, cinnamate 4-hydroxylase; 4CL, 4-hydroxycinnamoyl-CoA ligase; COMT, caffeic acid O-methyltransferase; F5H, ferulic acid/coniferaldehyde/coniferyl alcohol 5-hydroxylase; HCT, hydroxycinnamoyl-CoA:shikimate hydroxycinnamoyl transferase; LAC, laccase; PAL, Phe ammonia lyase; PCBER, phenylcoumaran benzylic ether reducatse; PLR, pinoresinol lariciresinol reductase; POX, peroxidase. Heat map red squares show genes up-regulated in inner stem tissues as compared with outer stem tissues, and green squares show genes up-regulated in outer stem tissues as compared with inner stem tissues (log2 ratio > 1.5 and < −1.5). [See online article for color version of this figure.]