Table 1. Phenotypes of monolignol biosynthesis pathway mutants in M. truncatula.
Data are averages ± sd for 16 biological replicates of each of two alleles (growth and reproduction) or three biological replicates of each of two alleles (lignin measurements). N/A, Not available due to developmental arrest. Stem tissue was harvested from plants that were beginning to produce their second flower. *, 0.001 < P < 0.01; **, 0.001 > P, Student’s t test.
| Parameter | Subparameter | Wild Type | cse | ccr1 | comt | ccoaomt | comt ccoaomt | hct |
|---|---|---|---|---|---|---|---|---|
| Growth | Plant height (cm) | 112.7 ± 11.2 | 12.2 ± 1.4** | 14.4 ± 1.3** | 109.6 ± 10.7 | 89.3 ± 8.5* | N/A | N/A |
| Leaf size (first leaf; mm) | 6.1 ± 0.4 | 4.2 ± 0.3** | 3.0 ± 0.3** | 6.1 ± 0.2 | 4.8 ± 0.8** | 3.0 ± 0.2** | 2.5 ± 0.2** | |
| Leaf size (cauline leaf; mm) | 17.5 ± 1.4 | 7.9 ± 0.4** | 5.5 ± 0.7** | 17.5 ± 1.3 | 10.9 ± 0.7** | N/A | N/A | |
| Reproduction | Flowering time (d after sowing) | 58.4 ± 1.9 | 75.9 ± 1.9** | 71.0 ± 2.9** | 63.6 ± 2.1** | 66.5 ± 2.5** | No flowering | No flowering |
| Seeds per pod | 7.1 ± 0.5 | 0.8 ± 0.6** | 0 | 7.0 ± 0.4 | 4.6 ± 1.2** | N/A | N/A | |
| Lignin amount | 10d plant (μmol g−1 dry wt) | 7.8 ± 0.1 | 3.9 ± 0.7** | 2.9 ± 0.7** | 3.4 ± 1.3** | 2.9 ± 0.6** | 1.9 ± 0.8** | 2.1 ± 0.0** |
| Stem tissue (μmol g−1 dry wt) | 161.9 ± 2.5 | 11.7 ± 1.0** | 6.6 ± 0.9** | 84.0 ± 7.3 | 73.3 ± 14.1** | N/A | N/A | |
| Lignin composition | 10d plant (H:G:S) | 6:80:14 | 39:44:17 | 9:78:13 | 8:89:3 | 13:70:16 | 20:76:4 | 65:30:4 |
| Stem tissue (H:G:S) | 0:87:13 | 55:33:11 | 4:87:8 | 1:99:0 | 2:81:17 | N/A | N/A | |
| Overall phenotype | Normal | Dwarf (strong) | Dwarf (strong) | Normal | Semidwarf | Dwarf (very strong) | Dwarf (very strong) | |
| Growth arrest | No | No | No | No | No | Yes | Yes | |