Skip to main content

Table 1 Examples of transgenic poplar lines targeting native monolignol synthesis genes

From: Use of the lignocellulose-degrading bacterium Caldicellulosiruptor bescii to assess recalcitrance and conversion of wild-type and transgenic poplar

Populus speciesTarget gene(s)Number transgenic lines reportedLignin (wt%)S/G ratioCarbohydrate content dataSource
Populus tremuloides Michx.4-Coumarate:CoA ligase (4CL1)811.84–20.60 (21.6)Cellulose (wt%)
45.95–50.83 (44.23)
[7]
Populus grandidentata x albap-Coumaryl-CoA 3′-hydroxylase (C3′H)910.51–21.03 (23.78)1.8– 3.1 (1.8)Glucose (wt%)
46.03–51.10 (45.69)
Xylose (wt%)
17.30–21.12 (17.87)
[4, 20]
Populus tremuloides4-Coumarate-CoA ligase (4CL1)513.1–16.0 (22.2)2.1–2.3 (2.2)Cellulose (wt%)
43.1–47.3 (41.4)
[12]
Coniferaldehyde 5-hydroxylase (CAld5H)519.7–22.4 (22.2)3.0–5.5 (2.2)Cellulose (wt%)
40.0–44.7 (41.4)
4CL1 Down-regulation and CAld5H Upregulation410.7–13.7 (22.2)2.6-3.6 (2.2)Cellulose (wt%)
49.2–53.3 (41.4)
Populus tremula x alba4-Coumarate:CoA ligase (4CL1)141.4–2.2 (1.8)[26]
Populus tremula x albaCinnamoyl-CoA reductase (CCR)2a19.1–19.6 (20.7)1.9 (1.9)Cellulose (wt%)
51.7–53.8 (50.9)
Hemi-cellulose (wt%)
19.7–20.9 (19.7)
[25]
2b16.6–19.8 (21.7)1.9–2.1 (2.0)Cellulose (wt%)
53.6–56.1 (52.4)
Hemi-cellulose (wt%)
19.7––20.7 (19.2)
Populus tremula x albaCaffeic acid/5-hydroxyferulic acid O-methyltransferase (COMT)2c19.3–19.5 (19.0)1.5 (2.2)[11]
Cinnamoyl alcohol dehydrogenase (CAD)3c18.0–18.3 (19.0)2.0 (2.2)
Populus tomentosa4-Coumarate:CoA ligase (4CL)222.16–22.68 (24.12)Cellulose (wt%)
49.58–51.53 (47.94)
[27]
Caffeoyl-CoA 3-O-methyltransferase (CCoAOMT)221.6–21.8 (24.1)Cellulose (wt%)
50.41–51.75 (47.94)
Populus nigra x maximowiczii4-Coumarate:CoA ligase (4CL)3d22.5–23.7 (23.6)S/V ratioe
0.6–1.9 (1.8)
Glucan (wt%)
36.1–39.7 (37.5)
Xylan (wt%)
13.8–14.9 (14.1)
[30]
  1. Values in parenthesis denote value reported for control/wild-type
  2. aField trial #1 (referred to as Belgian trial—10 month duration)
  3. bField trial #2 (referred to as French trial—20 month duration)
  4. cLapierre et al. reports data for various time periods in greenhouse and field trials. Data shown here for 6-month-old greenhouse grown trees
  5. dXiang et al. reports data for years 2 and 3 from lines grown in a mountain region and coastal region. Data reported here for year 3 trees grown in mountain region
  6. eS/V ratio is syringaldehyde to vanillin ratio