Article describes how the conversion of lignocellulosic feedstocks to fermentable sugar for biofuel production is inefficient, and most strategies to enhance efficiency directly target lignin biosynthesis, with associated negative growth impacts. The authors demonstrate, for both laboratory-and field-grown plants, that expression of Pag-miR408 in poplar significantly enhances saccharification, with no requirement for acid-pretreatment, while promoting plant growth.