Impact of xylan on field productivity and wood saccharification properties in aspen

Xylan that comprises roughly 25% of hardwood biomass is undesirable in biorefinery applications involving saccharification and fermentation. Efforts to reduce xylan levels have therefore been made many species, usually resulting improved saccharification. However, such modified plants not yet tested under field conditions. Here we evaluate the performance transgenic hybrid aspen lines with reduced assess their usefulness as short-rotation feedstocks for biorefineries. Three types were four-year tests RNAi constructs targeting either Populus GT43 clades B C ( GT43BC) corresponding Arabidopsis IRX9 IRX14 , respectively, involved backbone biosynthesis, GATL1.1 AtGALT1 reducing end sequence or ASPR1 encoding an atypical aspartate protease. Their productivity, wood quality traits, efficiency analyzed. The only differing significantly from wild type respect growth biotic stress resistance lines, whose stems 10% shorter narrower leaves showed increased arthropod damage. GT43BC exhibited no advantage despite superior greenhouse experiments. Wood had slightly density due thinner cell walls and, case larger diameters. was less extractable by alkali but more hydrolysable acid, glucuronosylation, its content all three lines. hemicellulose size distribution GALT1.1 skewed towards higher molecular mass compared type. These results provide experimental evidence functions biosynthesis suggest may regulate this process. In without pretreatment, provided 8-11% average glucose yields than wild-type plants. acid construct a yield increase on average. best each are thus predicted modestly outperform terms per hectare. evaluation xylan-reduced represents important step productive