Induced responses in stilbenes and terpenes in fertilized Norway spruce after inoculation with blue-stain fungus, Ceratocystis polonica

Abstract

In conifers, attacks by bark beetles and associated pathogenic fungi cause an induced wound response, which is characterized by accumulation of antifungal compounds and morphological changes that aid wound healing. In this article the stilbene and terpene concentrations of Norway spruce phloem were monitored as symptoms of induced wound responses in relation to changed nutrient conditions caused by fertilization. Plots of mature Norway spruce were fertilized with N, P or NPK. One year after fertilization the trees were artificially infected with Ceratocystis polonica, a pathogenic fungus associated with the bark beetle Ips typographus. The response of stilbenes to fungal inoculation was mainly qualitative. The concentration of stilbene glycosides in the phloem decreased, and in the immediate vicinity of the site of fungal inoculation, stilbene glycosides were less frequent than in mechanically wounded or unwounded phloem. Corresponding stilbene aglycones were most frequent inside the reaction lesion. The concentration of total stilbene aglycones near the inoculation site was significantly lower in N-fertilized trees than in unfertilized trees. Fungal inoculation caused a strong quantitative response in terpenes. The total terpene concentration of the phloem increased significantly, to almost 100 times greater near the inoculation site compared to the constitutive values. N fertilization significantly reduced the total terpene and total stilbene aglycone concentrations near the inoculation sites. Thus, N fertilization may reduce the ability of Norway spruce to defend itself against fungal pathogens.

Strong Induction of Minor Terpenes in Italian Cypress, Cupressus sempervirens, in Response to Infection by the Fungus Seiridium cardinale

“…Concentrations also were within the ranges of those in similar studies of other conifers infected by fungal pathogens (Blodgett and Stanosz 1998;Raffa and Berryman 1982b;Viiri et al 2001).…”

“…This phenomenon has been observed in numerous studies that address the reaction of conifer phloem and xylem to infection by fungal pathogens (Blodgett and Stanosz 1998;Bonello et al 2008;Faldt et al 2006;Raffa and Smalley 1995;Viiri et al 2001). In our study, the monoterpenes, well-known inhibitors of fungi mycelial growth and spore germination (Bakkali et al 2008;Kalemba and Kunicka 2003), and diterpenes, which also have strong antifungal activity (Eberhardt et al 1994;Kopper et al 2005;Kusumoto et al 2014), were the most reactive terpenoid groups in the phloem.…”

“…The information available for α-thujene (Raffa and Berryman 1982a;Zhao et al 2010) suggests that conifers do not use it as a defensive compound, but it may have some antifungal activity (Bajpai et al 2007). Sabinene (De Alwis et al 2009;Espinosa-garcia and Langenheim 1991;Kohzaki et al 2009) and terpinolene (Davis and Hofstetter 2011;Viiri et al 2001) are among the most induced compounds in some conifers under fungal attack, and possess antifungal properties against several phytopathogens and fungal endophytes RT retention time. Numbers and letters in bold type indicate statistically significant differences (REML, fixed = treatment, random = genotype, paired Tukey's post-hoc test, P<0.05) RT retention time.…”

“…In addition to the local terpene reactions to fungal infection, systemic responses have been found in non-infected tissues. Systemic changes in phloem terpene concentrations (Viiri et al 2001), foliar terpene concentrations (Schiller and Madar 1991), and foliar terpene emission rates (Faldt et al 2006) have been observed in conifers infected by fungi. These phenomena could enhance the defense of undamaged plant tissues, prepare the plant for new attacks related to the infection, or activate indirect defense strategies (Bonello et al 2008).…”

Higher Allocation to Low Cost Chemical Defenses in Invasive Species of Hawaii

“…The higher or lower content of different chemical compounds does not depend only on a defense strategy. Other environmental factors such as temperature or drought could explain changes of secondary metabolites contents such as terpenes since they are also involved in protection mechanisms in the face of abiotic Llusià, 2003, 2004;Peñuelas and Munné-Bosch, 2005;Lewis et al, 2006) and biotic (Viiri et al, 2001;Gershenzon and Dudareva 2007) stressors. Volatile terpenes also are involved in plant defense by multitrophic signalling (Dicke and Baldwin, 2010).…”