LIGNIFICATION REDUCTION IN PLANTS
The present invention provides an expression cassette containing a polynucleotide coding sequence for a hydroxycinnamoyl-CoA hydratase-lyase (HCHL), which is operably linked to a heterologous promoter. Also provided are methods of engineering plants that have reduced lignification, as well as cells, plant parts, and plant tissues from such engineered plants.
1 . An engineered plant comprising a heterologous hydroxycinnamoyl-CoA hydratase-lyase (HCHL) operably linked to a promoter.
2 . The engineered plant of claim 1 , wherein the promoter is a secondary cell wall-specific promoter.
3 . The engineered plant of claim 2 , wherein the secondary cell wall-specific promoter is an IRX5 promoter.
4 . The engineered plant of claim 1 wherein the HCHL is Pseudomonas fluorescens HCHL.
5 . (canceled)
6 . The engineered plant of claim 1 , wherein the plant is a dicot.
7 . The engineered plant of claim 1 wherein the plant is selected from the group consisting of Arabidopsis , poplar, eucalyptus, rice, corn, switchgrass, sorghum, millet, miscanthus, sugarcane, pine, alfalfa, wheat, soy, barley, turfgrass, tobacco, hemp, bamboo, rape, sunflower, willow, and Brachypodium.
8 . (canceled)
9 . A part of the plant of claim 1 .
10 . (canceled)
11 . Biomass comprising the plant, or part of the plant, of claim 1 .
12 . An isolated expression cassette comprising a polynucleotide sequence encoding a hydroxycinnamoyl-CoA hydratase-lyase (HCHL) and a heterologous promoter, the promoter operably linked to the polynucleotide sequence, wherein the promoter is a secondary cell wall-specific promoter.
13 . The expression cassette of claim 12 , wherein the HCHL is Pseudomonas fluorescens HCHL.
14 . The expression cassette of claim 12 , wherein the promoter is an IRX5 promoter.
15 . A plant cell comprising the expression cassette of claim 12 .
16 . A method for engineering a plant having reduced lignification, the method comprising:
(1) introducing a polynucleotide encoding a hydroxycinnamoyl-CoA hydratase-lyase (HCHL) into a plant, wherein the polynucleotide in the plant is operably linked to a promoter; and
(2) culturing the plant under conditions in which the HCHL is expressed, thereby reducing lignification in the plant.
17 . The method of claim 16 , wherein the promoter is heterologous to the plant.
18 . (canceled)
19 . The method of claim 16 , wherein the promoter is a secondary cell wall-specific promoter.
20 . The method of claim 19 , wherein the secondary cell wall-specific promoter is an IRX5 promoter.
21 . The method of claim 16 , wherein the HCHL is Pseudomonas fluorescens HCHL.
22 . (canceled)
23 . The method of claim 16 , wherein the plant is a dicot.
24 . The method of claim 16 , wherein the plant is selected from the group consisting of Arabidopsis , poplar, eucalyptus, rice, corn, switchgrass, sorghum, millet, miscanthus, sugarcane, pine, alfalfa, wheat, soy, barley, turfgrass, tobacco, hemp, bamboo, rape, sunflower, willow, and Brachypodium.
25 . A method of obtaining soluble sugars, the method comprising incubating the biomass of claim 11 in a saccharification reaction.