Traumatic resin ducts

Martin D., Tholl D., Gershenzon J. and Bohlmann J. (2002) Methyl jasmonate induces traumatic resin ducts, terpenoid resin biosynthesis and terpenoid accumulation in developing xylem of Norway spruce stems. Plant Physiol. 129, 100-1018. 

McKay, S.A., Hunter, W.L., Godard, K.A., Wang, S.X., Martin, D.M., Bohlmann, J. and Plant, A.L. (2003) Insect attack and wounding induce traumatic resin duct development and gene expression of (—)-pinene synthase in Sitka spruce. Plant Physiol, 133, 368-78. 

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.

NAGY, N.E., FRANCESCHI, V.R., SOLHEIM, H., KREKLING, T., CHRISTIANSEN, E., Wound-induced traumatic resin duct development in stems of Norway spruce (Pinaceae) anatomy and cytochemical traits., Amer. J. Bot., 2000, 87,302-313. 

HUDGINS, J.W., FRANCESCHI, V.R., Methyl jasmonate-induced ethylene production is responsible for conifer phloem defense responses and reprogramming of stem cambial zone for traumatic resin duct formation., Plant Physiol, 2004, 135, 2134-2149. 

Our recent research suggests organ-, tissue-, and cell-specific localization of constitutive and induced terpenoid defense pathways in conifers. For example, linalool synthase (PaTPS-Lin) seems to be preferentially expressed in needles of Norway spruce and Sitka spruce with little or no expression in sterns. ft is also likely that expression of PaTPS-Lin in spruce needles is not associated with resin ducts but could reside in other cells involved with induced terpenoid emission. In contrast, we can speculate that most other mono-TPS and di-TPS are associated with epithelial cells of constitutive and induced resin ducts. The possible localization of conifer sesqui-TPS is difficult to predict. Furthermore, the exact spatial and temporal patterns of terpenoid pathway gene expression associated with traumatic resin duct development in the cambium zone and outer xylem remain to be studied at the tissue and cell level. In situ hybridization and immuno-localization of TPS will address these open questions. These methods have worked well in identifying cell type specific gene and protein expression of alkaloid formation in opium poppy Papaver somniferum) As the biochemistry of induced terpene defenses and the development of traumatic resin ducts have been well described in spruce, this system is ideal for future studies of tissue- and cell-specific localization of transcripts and proteins associated with oleoresin defense and induced volatile emissions in conifers. In addition, the advent of laser dissection microscopy techniques presents a fascinating means by which to further address RNA and protein analysis in a tissue-and cell-specific manner. These techniques, when applied to the cambium zone, xylem mother cells, and the epithelial cells that surround traumatic resin ducts, and will allow a temporal and spatial analysis of cellular functions occurring in the traumatic resin response. 

Fahn A, WerkerE, BentzurP (1979) Seasonal effects of wounding and growth-substances on development of traumatic resin ducts in Cednis libani. New Phytol 82(2) 537... 

Luchi N, Ma R, Capretti P, Bonello P (2005) Systemic induction of traumatic resin ducts and resin flow in Austrian pine by wounding and inoculation with Sphaeropsis sapinea and Diplodia scrobiculata. Planta 221(l) 75-84. doi 10.1007/s00425-004-1414-3... 

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