title: Intra-specific variations in expression of stress-related genes in beech progenies are stronger than drought-induced responses.
abstract: Rapidly decreasing water availability as a consequence of climate change is likely to endanger the range of long-lived tree species. A pressing question is, therefore, whether adaptation to drought exists in important temperate tree species like European beech (Fagus sylvatica L.), a wide-spread, dominant forest tree in Central Europe. Here, five beech stands were selected along a precipitation gradient from moist to dry conditions. Neutral genetic markers revealed strong variation within and little differentiation between the populations. Natural regeneration from these stands was transferred to a common garden and used to investigate the expression of genes for abscisic acid (ABA)-related drought signaling [9-cis-epoxy-dioxygenase (NCED), protein phosphatase 2C (PP2C), early responsive to dehydration (ERD)] and stress protection [ascorbate peroxidase (APX), superoxide dismutase (SOD), aldehyde dehydrogenase (ALDH), glutamine amidotransferase (GAT)] that are involved in drought acclimation. We hypothesized that progenies from dry sites exhibit constitutively higher expression levels of ABA- and stress-related genes and are less drought responsive than progenies from moist sites. Transcript levels and stress responses (leaf area loss, membrane integrity) of well-irrigated and drought-stressed plants were measured during the early, mid- and late growing season. Principal component (PC) analysis ordered the beech progenies according to the mean annual precipitation at tree origin by the transcript levels of SOD, ALDH, GAT and ERD as major loadings along PC1. PC2 separated moist and drought treatments with PP2C levels as important loading. These results suggest that phosphatase-mediated signaling is flexibly acclimated to the current requirements, whereas stress compensatory measures exhibited genotypic variation, apparently underlying climate selection. In contrast to expectation, the drought responses were less pronounced than the progeny-related differences and the transcript levels were constitutively lower in beeches from dry than from moist sites. These results imply that beeches from dry origins may have evolved mechanisms to avoid oxidative stress.
authors.affiliation: Forstbotanik und Baumphysiologie, Büsgen-Institute, Georg-August Universität Göttingen, Büsgenweg 2, 37077 Göttingen, Germany.
authors.forename: Caroline
authors.initials: C
authors.lastname: Carsjens
authors.affiliation: Forstbotanik und Baumphysiologie, Büsgen-Institute, Georg-August Universität Göttingen, Büsgenweg 2, 37077 Göttingen, Germany.
authors.forename: Quynh
authors.initials: Q
authors.lastname: Nguyen Ngoc
authors.affiliation: Forstbotanik und Baumphysiologie, Büsgen-Institute, Georg-August Universität Göttingen, Büsgenweg 2, 37077 Göttingen, Germany.
authors.forename: Jonas
authors.initials: J
authors.lastname: Guzy
authors.affiliation: Plant Ecology, Albrecht von Haller Institute for Plant Sciences, Georg-August Universität Göttingen, Untere Karspüle 2, 37073 Göttingen, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Knutzen
authors.affiliation: Plant Ecology, Albrecht von Haller Institute for Plant Sciences, Georg-August Universität Göttingen, Untere Karspüle 2, 37073 Göttingen, Germany.
authors.forename: Ina Christin
authors.initials: IC
authors.lastname: Meier
authors.affiliation: Forstgenetik und Forstpflanzenzüchtung, Büsgen-Institute, Georg-August Universität Göttingen, Büsgenweg 2, 37077 Göttingen, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Müller
authors.affiliation: Forstgenetik und Forstpflanzenzüchtung, Büsgen-Institute, Georg-August Universität Göttingen, Büsgenweg 2, 37077 Göttingen, Germany.
authors.forename: Reiner
authors.initials: R
authors.lastname: Finkeldey
authors.affiliation: Plant Ecology, Albrecht von Haller Institute for Plant Sciences, Georg-August Universität Göttingen, Untere Karspüle 2, 37073 Göttingen, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Leuschner
authors.affiliation: Forstbotanik und Baumphysiologie, Büsgen-Institute, Georg-August Universität Göttingen, Büsgenweg 2, 37077 Göttingen, Germany apolle@gwdg.de.
authors.forename: Andrea
authors.initials: A
authors.lastname: Polle
mesh_terms: D000040:Abscisic Acid / Q000235:genetics / Q000378:metabolism; D000064:Acclimatization / Q000235:genetics*; D002980:Climate; D057231:Climate Change; D055864:Droughts; D029964:Fagus / Q000235:genetics* / Q000378:metabolism; D017343:Genes, Plant; D014644:Genetic Variation; D005838:Genotype; D018384:Oxidative Stress / Q000235:genetics; D011891:Rain; D015398:Signal Transduction; D013312:Stress, Physiological / Q000235:genetics*; D014158:Transcription, Genetic; D014197:Trees; D014867:Water
chemical_list: D014867:Water; D000040:Abscisic Acid
keywords: ABA; antioxidants; beech (Fagus sylvatica); drought; genetic distance; growing season; stress