Table II. Lignin-associated changes in wild-type and ir-CAD plants when grown under PF and UF environments in their native habitat in southwestern Utah.
Values are means ± se. Asterisks indicate significant differences among the genotypes (paired t test: * P < 0.05, *** P < 0.001); n = 5 for transcript abundance quantification and enzymatic activity analysis, and n = 3 for all lignin analyses. n.d., Not detected.
| Parameter | Sample |
|||
|---|---|---|---|---|
| PF Wild Type | PF ir-CAD | UF Wild Type | UF ir-CAD | |
| Gene (transcript abundance %; relative to GH wild type; apical stem) | ||||
| NaCAD | 123.63 ± 15.61 | 4.40 ± 1.06*** | 119.82 ± 13.20 | 3.43 ± 0.31*** |
| NaCAD1 | 102.49 ± 12.03 | 6.55 ± 1.83*** | 87.50 ± 25.31 | 7.49 ± 2.49*** |
| Enzyme (nkat mg-1 protein; apical stem) | ||||
| CAD activity | 0.38 ± 0.02 | 0.036 ± 0.01*** | 0.3 ± 0.05 | 0.025 ± 0.00*** |
| SAD activity | 0.27 ± 0.03 | 0.03 ± 0.01*** | 0.25 ± 0.04 | 0.019 ± 0.01*** |
| Lignin composition | ||||
| Thioacidolysis-released (β-O-4-linked) monomers (µmol g-1 Klason lignin); basal stem and NMR data | ||||
| H units | 51.43 ± 4.25 | 34.28 ± 11.45 | 96.48 ± 13.94 | 59.12 ± 29.82 |
| G units | 1,119.20 ± 84.10 | 447.97 ± 62.24*** | 919.12 ± 102.63 | 487.50 ± 82.16*** |
| S units | 2,467.49 ± 82.30 | 304.10 ± 54.39*** | 2,401.2 ± 268.58 | 582.71 ± 182.75*** |
| S/G (thio) | 72.3:27.7 | 54.4:45.6 | ||
| S/G (thio) | 2.20 | 0.67 | 2.61 | 1.20 |
| S/G (NMR) | 56:44 | 48:52 | ||
| S/G (NMR) | 1.28 | 0.91 | ||
| Coniferaldehyde | n.d. | 7.83 ± 1.35 | n.d. | 11.07 ± 1.47 |
| Sinapaldehyde | n.d. | 48.97 ± 2.90 | n.d. | 53.48 ± 7.23 |
| End group monomers (thioacidolysis) | ||||
| Vanillin | n.d. | 6.02 ± 0.50 | n.d. | 2.16 ± 0.08 |
| Syringaldehyde | n.d. | 32.43 ± 2.01 | n.d. | 14.27 ± 1.27 |
| Klason lignin content (%; basal stem) | 26.07 ± 1.99 | 27.84 ± 3.27 | 26.60 ± 1.13 | 25.27 ± 1.56 |