On the Cover: Methyl jasmonate alters xylem differentiation in conifers. The cross section of a white spruce (Picea glauca) leader on the cover shows two concentric rings of traumatic resin ducts formed in response to feeding and oviposition by white pine weevil (Pissodes strobi). Martin et al. (pp. 1003–1018) showed that methyl jasmonate mimics the effect of stem-boring insects in Norway spruce (Picea abies), causing a complex, transient change in xylem development. The induced xylem defense response includes formation of resin canal cells instead of tracheids, xylem-specific differential induction of prenyltransferases and terpenoid synthases, and accumulation of resin diterpenoids and monoterpenoids (image by René I. Alfaro).