Fig. 1

AnAXE1 overexpressing aspen exhibits normal growth and reduced cell wall acetyl content. a Appearance of 2-month-old trees of transgenic lines 8, 4, and 17 compared to WT. b Stem cross sections stained with phloroglucinol from representative line 17 and WT trees. Scale Bar 100 μm. c Acetyl esterase-specific activity observed in soluble and wall-bound protein fractions extracted from developing wood with p-naphthyl acetate used as substrate. d Cell wall acetyl content determined by acetic acid release after saponification. Data in c and d are mean ± SE, n = 5 biological replicates. Asterisks mark lines significantly different from WT: **P ≤ 0.05; ***P ≤ 0.01 (Student’s t test). e OPLS-DA scatter plot of FT-IR data obtained for wood powder from transgenic and WT trees. f Corresponding loading plot, showing variables that contributed to the separation. Signals assigned to acetyl esters (1240, 1370, and 1740), indicated by blue arrows, were more intense in the WT; signals assigned to absorbed water and lignin (1640 and 1596, respectively), indicated by orange arrows, were more intense in transgenic trees