Induced defenses anatomical defense

Fig. 1.1 Induced anatomical defense responses in Norway spruce. (A, B) Formation of a ring of new, traumatic resin ducts (TD, arrowheads) in the xylem of 2-year-old Norway spruce saplings after application of methyl jasmonate. A large cortical resin duct (CD) can be observed in the phloem, but these ducts do not appear to respond to methyl jasmonate treatment. (C) Normal phloem and sapwood anatomy of an older tree, with concentric rings of polyphenolic parenchyma cells (PP) in the phloem above the cambium (X) and normal wood below. (D) After treatment with methyl jasmonate or fungal infection the PP cells increase greatly in size and traumatic resin ducts (arrowheads) forms in the wood.

HUDGINS, J.W., CHRISTIANSEN, E., FRANCESCHI, V.R., Methyl jasmonate induces changes mimicking anatomical defenses in diverse members of the Pinaceae, Tree Physiol, 2003,23,361-371. 

Recent studies have described the complex, constitutive, and MeJA- and insect-induced terpenoid defenses in Norway spruce and Sitka spruce at anatomical, chemical, and biochemical levels. " Miller et al. compared the effect of MeJA treatment and white pine weevil attack on induced terpenoid defenses in Sitka spruce. They found that MeJA and real insects induce very similar terpenoid responses at the biochemical and molecular levels. The cloning and functional characterization of a family of ten, functionally diverse Norway spruce TPS genes not only allowed an improved phylogeny of the conifer TPS-d gene family but also allowed a detailed molecular and biochemical characterization of induced changes in terpenoid metabolite profiles in spruce defense. Many of the products of the recently identified Norway spruce TPS genes correspond with components of terpenoid metabolite profiles after MeJA treatment or insect attack in species of spruce. Our work on Norway spruce terpenoid responses to MeJA treatment " is discussed here with an emphasis on those compounds that are products of the newly characterized spruce TPS genes. ... 

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