Modified plants and methods for producing modified lignin by modulating expression of acyltransferases

1. A cell wall or biomass obtained from a genetically modified plant comprising a nucleic acid encoding a promoter operatively linked to an open reading frame (ORF) encoding an exogenous acyltransferase wherein the acyltransferase catalyzes the addition of an acceptor to a lignin carrier moiety; and a lignin polymer comprising the lignin carrier moiety with the acceptor; wherein the promoter is a fiber-specific promoter, a vessel-specific promoter, or a secondary cell wall promoter; the acyltransferase is hydroxycinnamoyl/benzoyl-CoA:anthranilate N-hydroxycinnamoyl/benzoyltransferase (HCBT), or hydroxycinnamoyl-CoA:hydroxyanthranilate N-hydroxycinnamoyltransferase (HHT); and the acceptor is a (hydroxyl)anthranilate; and the lignin polymers have an average molecular weight that is lower than the average molecular weight of the lignin polymers of the plant that is not genetically modified.

2. A method to produce lignin modified with an acceptor, comprising: (a) providing a genetically modified plant comprising a nucleic acid encoding a promoter operatively linked to an open reading frame (ORF) encoding an exogenous acyltransferase wherein the acyltransferase catalyzes the addition of an acceptor to a lignin carrier moiety; and a lignin polymer comprising the lignin carrier moiety with the acceptor; wherein the promoter is a fiber-specific promoter, a vessel-specific promoter, or a secondary cell wall promoter; the acyltransferase is hydroxycinnamoyl/benzoyl-CoA:anthranilate N-hydroxycinnamoyl/benzoyltransferase (HCBT), or hydroxycinnamoyl-CoA:hydroxyanthranilate N-hydroxycinnamoyltransferase (HHT); and the acceptor is a (hydroxyl)anthranilate; and the lignin polymers have an average molecular weight that is lower than the average molecular weight of the lignin polymers of the plant that is not genetically modified, (b) growing the genetically modified plant, (c) isolating the lignin of the plant from the rest of the plant, and (d) separating the acceptors from the lignin.

3. The cell wall or biomass of claim 1 , wherein the promoter is the fiber-specific promoter.

4. The cell wall or biomass of claim 3 , wherein the fiber-specific promoter is pNST or pLAC17.

5. The cell wall or biomass of claim 1 , wherein the promoter is the vessel-specific promoter.

6. The cell wall or biomass of claim 1 , wherein the promoter is the secondary cell wall promoter.

7. The cell wall or biomass of claim 6 , wherein the secondary cell wall promoter is pIRX8 or pIRX5.

8. The method of claim 2 , wherein the promoter is the fiber-specific promoter.

9. The method of claim 8 , wherein the fiber-specific promoter is pNST or pLAC17.

10. The method of claim 2 , wherein the promoter is the vessel-specific promoter.

11. The method of claim 2 , wherein the promoter is the secondary cell wall promoter.

12. The method of claim 11 , wherein the secondary cell wall promoter is pIRX8 or pIRX5.