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Research article - Peer-reviewed, 2022

Interaction of drought- and pathogen-induced mortality in Norway spruce and Scots pine

Gomez-Gallego, Mireia; Galiano, Lucia; Martinez-Vilalta, Jordi; Stenlid, Jan; Capador-Barreto, Hernan D.; Elfstrand, Malin; Camarero, J. Julio; Oliva, Jonas

Abstract

Pathogenic diseases frequently occur in drought-stressed trees. However, their contribution to the process of drought-induced mortality is poorly understood. We combined drought and stem inoculation treatments to study the physiological processes leading to drought-induced mortality in Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) saplings infected with Heterobasidion annosum s.s. We analysed the saplings' water status, gas exchange, nonstructural carbohydrates (NSCs) and defence responses, and how they related to mortality. Saplings were followed for two growing seasons, including an artificially induced 3-month dormancy period. The combined drought and pathogen treatment significantly increased spruce mortality; however, no interaction between these stressors was observed in pine, although individually each stressor caused mortality. Our results suggest that pathogen infection decreased carbon reserves in spruce, reducing the capacity of saplings to cope with drought, resulting in increased mortality rates. Defoliation, relative water content and the starch concentration of needles were predictors of mortality in both species under drought and pathogen infection. Infection and drought stress create conflicting needs for carbon to compartmentalize the pathogen and to avoid turgor loss, respectively. Heterobasidion annosum reduces the functional sapwood area and shifts NSC allocation patterns, reducing the capacity of trees to cope with drought.

Keywords

carbon starvation; conifer; drought-induced tree death; hydraulic failure; necrotrophic pathogen; sapwood

Published in

Plant, Cell and Environment
2022,
Publisher: WILEY

Authors' information

Gomez-Gallego, Mireia (Gomez-Gallego, Mireia )
Swedish University of Agricultural Sciences, Department of Forest Mycology and Plant Pathology
Gomez-Gallego, Mireia
INRAE
Galiano, Lucia
Centro de Investigacion Ecologica y Aplicaciones Forestales (CREAF)
Galiano, Lucia
Autonomous University of Barcelona
Martinez-Vilalta, Jordi
Centro de Investigacion Ecologica y Aplicaciones Forestales (CREAF)
Martinez-Vilalta, Jordi
Autonomous University of Barcelona
Swedish University of Agricultural Sciences, Department of Forest Mycology and Plant Pathology
Swedish University of Agricultural Sciences, Department of Forest Mycology and Plant Pathology
Camarero, J. Julio
Consejo Superior de Investigaciones Cientificas (CSIC)
Oliva, Jonas
Universitat de Lleida

UKÄ Subject classification

Forest Science

Publication Identifiers

DOI: https://doi.org/10.1111/pce.14360

URI (permanent link to this page)

https://res.slu.se/id/publ/117568