Field and saccharification performances of poplars severely downregulated in CAD1

• DOI: 10.1111/nph.18366
• Publication Date: 2022-07-09T06:49:02Z
• Authors: Barbara De Meester; Rebecca Van Acker; Marlies Wouters; Silvia Traversari; Marijke Steenackers; Jenny Neukermans; Frank Van Breusegem; Annabelle Déjardin; Gilles Pilate; Wout Boerjan
• Keywords: Cinnamyl-alcohol dehydrogenase; Monolignol; Cinnamyl alcohol; Lignocellulosic Biomass

Lignin is one of the main factors causing lignocellulosic biomass recalcitrance to enzymatic hydrolysis. Glasshouse-grown poplars severely downregulated for CINNAMYL ALCOHOL DEHYDROGENASE 1 (CAD1), enzyme catalysing last step in monolignol-specific branch lignin biosynthesis, have increased saccharification yields and normal growth. Here, we assess performance these hpCAD field under short rotation coppice culture two consecutive rotations yr 3 yr. While 1-yr-old wood had 10% less lignin, 3-yr-old wild-type levels. Because their altered cell wall composition, including elevated levels cinnamaldehydes, both showed enhanced upon harsh alkaline pretreatments (up +85% +77%, respectively). In contrast with previous trials (CAD), displayed leaning phenotypes, early bud set, flowering yield penalties. Moreover, enlarged vessels, decreased density reduced relative free water contents. Our data show that phenotypes CAD-deficient are strongly dependent on environment underpin importance translating basic research towards applications.