Low-density Ceratocystis polonica inoculation of Norway spruce (Picea abies) triggers accumulation of monoterpenes with antifungal properties

The Differential Effects of the Blue-Stain Fungus Leptographium qinlingensis on Monoterpenes and Sesquiterpenes in the Stem of Chinese White Pine (Pinus armandi) Saplings

“…In our experiment, total monoterpene concentrations in the phloem and xylem in P. armandi saplings after inoculation of the blue-stain fungus L. qinlingensis were significantly higher than in both control and untreated saplings. The results are in accordance with several previous reports in conifers [19][20][21][22][23][24][25]31], where total monoterpene concentrations increased significantly after the inoculation of blue-stain fungi. However, the comparison of the increases in total monoterpene concentrations found in this study with the results of previous studies may be influenced by differences in experimental design, such as differences in the treatment type, the age of the tree, and the sampling time points [21,31].…”

“…Moreover, monoterpenes (α-pinene, β-pinene, myrcene, terpinolene, sabinene, ∆-3-carene or limonene) have been shown to increase in response to fungal inoculation [20,[35][36][37]. Limonene and β-pinene, produced in the defence response of P. abies, have been found to be the most potential inhibitors to the growth of the blue-stain fungus Ceratocystis polonica [21]. Similarly, our data suggest that β-pinene and limonene + β-phellandrene may play a critical role in inhibiting the spread of the blue-stain fungus L. qinlingenesis.…”

Defence reactions of mature Norway spruce (Picea abies) before and after inoculation of the blue-stain fungus Endoconidiophora polonica in a drought stress experiment

“…Likely, genetic variability in defence capacity apart from differences in water supply played an important role in constitutive defence characteristics of the sample trees. In response to fungal infection, conifers develop necrotic phloem lesions by impregnating affected tissues with resin, increasing monoterpene levels and changing the composition of phenols in the secondary phloem (Lieutier et al 1996;Novak et al 2014). In various inoculation experiments, resistant and more susceptible spruce clones were shown to differ in the stimulation of metabolic pathways leading to particular phenolic monomers after wounding and fungal attack (Brignolas et al 1995(Brignolas et al , 1998.…”

“…Such link between advanced physiological stress and limited constitutive defence capability in terms of less resin flow was recently demonstrated in response to drought-manipulation in stands of Pinus edulis (Pinyon pine) and P. abies (Gaylord et al 2013;Netherer et al 2015). Drought stress positively or negatively influences the capacity of conifers to prevent the spreading of microorganisms after invasion via hypersensitive wound reaction, which is characterised by the formation of necrotic areas and impregnation of tissues with resinous and phenolic compounds Novak et al 2014). Mild water deficiency causing only moderate stress even enhanced tree resistance of pines (P. yunnanensis) in response to inoculation of a bark beetle associated fungal pathogen (Leptographium yunnanense), which was indicated by limited fungus extension and reaction zone length in the phloem (Sallé et al 2008).…”

Electrophysiological and behavioural responses of Ips typographus (L.) to trans-4-thujanol—a host tree volatile compound

“…For instance, essential oil of marjoram contains trans-4-thujanol as one of the main components (Novak et al 2000), and the oil acts as a fungicide (Sharma et al 2011). We assume that trans-4-thujanol may have an antifungal property, like some Norway spruce monoterpenes, which can inhibit growth of the blue stain fungus, Ceratocystis polonica (Siem) C. Moreau (Novak et al 2014). As fungi within galleries excavated by bark beetles are important for I. typographus larval feeding (Lieutier et al 2009), the presence of a certain concentration of trans-4-thujanol might be unfavourable for bark beetle broods.…”