Oak powdery mildew (Erysiphe alphitoides)-induced volatile emissions scale with the degree of infection in Quercus robur.

Abstract

Oak powdery mildew (Erysiphe alphitoides) is a major foliar pathogen of Quercus robur often infecting entire tree stands. In this study, foliage photosynthetic characteristics and constitutive and induced volatile emissions were studied in Q. robur leaves, in order to determine whether the changes in foliage physiological traits are quantitatively associated with the degree of leaf infection, and whether infection changes the light responses of physiological traits. Infection by E. alphitoides reduced net assimilation rate by 3.5-fold and isoprene emission rate by 2.4-fold, and increased stomatal conductance by 1.6-fold in leaves with the largest degree of infection of ∼60%. These alterations in physiological activity were quantitatively associated with the fraction of leaf area infected. In addition, light saturation of net assimilation and isoprene emission was reached at lower light intensity in infected leaves, and infection also reduced the initial quantum yield of isoprene emission. Infection-induced emissions of lipoxygenase pathway volatiles and monoterpenes were light-dependent and scaled positively with the degree of infection. Overall, this study indicates that the reduction of foliage photosynthetic activity and constitutive emissions and the onset of stress volatile emissions scale with the degree of infection, but also that the infection modifies the light responses of foliage physiological activities.

• Authors: Lucian Copolovici, Fred Väärtnõu, Miguel Portillo Estrada, Ülo Niinemets
• Journal: Tree physiology (Tree Physiol) Vol. 34 Issue 12 Pg. 1399-410 (Dec 2014) ISSN: 1758-4469 [Electronic] Canada
• PMID: 25428827 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: [email protected].

Chemical References

• Butadienes
• Hemiterpenes
• Monoterpenes
• Oils, Volatile
• Pentanes
• Terpenes
• isoprene

Topics

• Ascomycota
• Butadienes (metabolism)
• Environment
• Hemiterpenes (metabolism)
• Light
• Monoterpenes (metabolism)
• Oils, Volatile (metabolism)
• Pentanes (metabolism)
• Photosynthesis
• Plant Diseases (microbiology)
• Plant Leaves (metabolism, microbiology, physiology)
• Quercus (metabolism, microbiology, physiology)
• Terpenes (metabolism)