Preliminary study of the monoterpene response of three pines to Ophiostoma clavigerum (Ascomycetes : Ophiostomatales) and two chemical elicitors

Abstract

Summary — The monoterpene response of phloem and sapwood of individual pines belonging to 3 species (Pinus contorta, Pinus ponderosa and Pinus monticola) to inoculation with Ophiostoma clavigerum and injection with chitosan, a proteinase inhibitor-inducing factor and a control buffer, was investigated quantitatively and qualitatively. The total quantity of monoterpene in the reactive tissues increased with each treatment but to different levels. In each tree, the monoterpene composition of the reactive tissues differed from that of the unwounded tissues, but was the same whatever the treatment, even in the case of an injection with buffer control. In addition, phloem and sapwood responses were qualitatively identical although constitutive compositions differed greatly. The composition of reactive tissues was not very different from that of unwounded sapwood. The direction of variation of each monoterpene from unwounded to reactive tissues differed according to the particular tree. Only phellandrene + limonene reacted consistently. From these results we cannot conclude that chitosan is a natural elicitor, and the non-specificity of the response for the aggression favors the hypothesis that an elicitor originates from the tree itself. Because of this non-specificity, and the fact that the three trees responded in a qualitatively different manner, we suggest that the qualitative monoterpene response of the tree is not adapted to any specific aggressor even though these trees are usually hosts of the same bark beetle-fungus complex. Thus, the role of monoterpenes in the induced defensive response is very likely a quantitative and dose-dependent relationship.

Origin identification of Pinus nigra populations in southwestern Europe using terpene composition variations

“…The compounds which were found in traces (x<0.05%, sensu von Rudloff 1975; Lieutier et al 1991) were eliminated, as were the compounds with unreliable arithmetic mean values (x<2.26 SE, t-distribution, n=10, df=9, P=0.05) and the compounds which did not show significant differences between mean values of populations (df 15 and 144; F exp = from 0.88 to 1.68; α>0.05). Seven compounds (camphene, trans-ocimene, methyl thymol, α-humulene, bicyclogermacrene+α-muurolene and γ -cadinene) were also eliminated, which with the selected components show high correlation coefficient values (r 2 >0.7).…”

“…Helium was the carrier gas and the velocity of the flow was 45 ml/min. The program MaximaBaseline 810 (1991, Millipore Corporation, Massachusetts, USA, 1991 15.6 (13.5) normal distribution (within populations) were repeated (rechromatographed) to monitor their accuracy, i.e. to avoid artefacts.…”

Mechanisms of Resistance in Conifers and Bark beetle Attack Strategies

“…This nonspecific response to various aggressors was observed by Reid et al (1967) and Wong and Berryman (1977) through similarities of the tree's response to wounding and fungus aggression, but they did not specifically mention it. It has now been clearly demonstrated at the chemical level through analyses of the monoterpene and phenol contents of the phloem reaction zones, in various conifer species (Cook and Hain, 1985;Delorme and Lieutier, 1990;Lieutier et al, 1991b;Raffa and Smalley, 1995;Popp et al, 1995;Brignolas et al, 1995a;Bois and Lieutier, 1997) and at the histological level (Lieutier and Berryman, 1988a;Franceschi et al, 1998). Changes in the nature of the aggressor elicit only quantitative variations in the tree's hypersensitive response.…”

Nitrogen Concentration in Mountain Pine Beetle Larvae Reflects Nitrogen Status of the Tree Host and Two Fungal Associates

“…Earlier work on bark beetle-fungal-tree interactions examined the direct effects of inoculating trees with bark beetle-associated fungi (i.e., Raffa and Berryman 1983, Cook and Hain 1986, Lieutier et al 1991. Both O. clavigerum and O. montium are capable of staining the sapwood of infected trees, and O. clavigerum was demonstrated to be capable of causing mortality of mature trees (Yamaoka et al 1995).…”