title: 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.affiliation: Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, 1 Kreutzwaldi, 51014 Tartu, Estonia Institute of Research, Development, Innovation in Technical and Natural Sciences, 'Aurel Vlaicu' University, 2 Elena Dragoi, 310330 Arad, Romania lucian.copolovici@emu.ee.
authors.forename: Lucian
authors.initials: L
authors.lastname: Copolovici
authors.affiliation: Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, 1 Kreutzwaldi, 51014 Tartu, Estonia.
authors.forename: Fred
authors.initials: F
authors.lastname: Väärtnõu
authors.affiliation: Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, 1 Kreutzwaldi, 51014 Tartu, Estonia Centre of Excellence PLECO (Plant and Vegetation Ecology), Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610, Wilrijk, Belgium.
authors.forename: Miguel
authors.initials: M
authors.lastname: Portillo Estrada
authors.affiliation: Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, 1 Kreutzwaldi, 51014 Tartu, Estonia Estonian Academy of Sciences, 6 Kohtu, 10130 Tallinn, Estonia.
authors.forename: Ülo
authors.initials: Ü
authors.lastname: Niinemets
mesh_terms: D001203:Ascomycota; D002070:Butadienes / Q000378:metabolism; D004777:Environment; D045782:Hemiterpenes / Q000378:metabolism; D008027:Light; D039821:Monoterpenes / Q000378:metabolism; D009822:Oils, Volatile / Q000378:metabolism*; D010420:Pentanes / Q000378:metabolism; D010788:Photosynthesis; D010935:Plant Diseases / Q000382:microbiology*; D018515:Plant Leaves / Q000378:metabolism / Q000382:microbiology / Q000502:physiology; D029963:Quercus / Q000378:metabolism / Q000382:microbiology* / Q000502:physiology; D013729:Terpenes / Q000378:metabolism*
chemical_list: D002070:Butadienes; D045782:Hemiterpenes; D039821:Monoterpenes; D009822:Oils, Volatile; D010420:Pentanes; D013729:Terpenes; C005059:isoprene
keywords: green leaf volatiles; induced emissions; isoprene emission; light dependency; monoterpene emission; photosynthesis; quantitative responses; volatile organic compounds