|Publication Type:||Journal Article|
|Year of Publication:||2011|
|Authors:||Berthet, S, Demont-Caulet, N, Pollet, B, Bidzinski, P, Cézard, L, Le Bris, P, Borrega, N, Hervé, J, Blondet, E, Balzergue, S, Lapierre, C, Jouanin, L|
|Journal:||The Plant Cell|
Peroxidases have been shown to be involved in the polymerization of lignin precursors, but it remains unclear whether laceases (EC 184.108.40.206) participate in constitutive lignification. We addressed this issue by studying lacease T-DNA insertion mutants in Arabidopsis thaliana. We identified two genes, LAC4 and LAC17, which are strongly expressed in stems. LAC17 was mainly expressed in the interfascicular fibers, whereas LAC4 was expressed in vascular bundles and interfascicular fibers. We produced two double mutants by crossing the LAC17 (lad 7) mutant with two LAC4 mutants (Iac4-1 and Iac4~ 2).The single and double mutants grew normally in greenhouse conditions. The single mutants had moderately low lignin levels, whereas the stems of Iac4-1 lad7 and lac4-2 lad7 mutants had lignin contents that were 20 and 40% lower than those of the control, respectively. These lower lignin levels resulted in higher saccharification yields. Thioacidolysis revealed that disrupting LAC17 principally affected the deposition of G lignin units in the interfascicular fibers and that complementation of Iad7 with LAC17 restored a normal lignin profile. This study provides evidence that both LAC4 and LAC17 contribute to the constitutive lignification of Arabidopsis stems and that LAC17 is involved in the deposition of G lignin units in fibers.
|Short Title:||The Plant Cell|