Adaptation of Trees to Climate Change: Mechanisms Behind Physiological and Ecological Resilience and Vulnerability

Climate change negatively affects forest health. The increasing occurrence of extreme climate events such as heatwaves, long periods of drought, and flooding episodes, followed by large and severe insect outbreaks and pathogen infestations, currently represent a severe threat for forests. Besides increases in intensity, frequency, and severity of these events, the often-quick succession of abiotic and biotic stresses make forests even more vulnerable. Under such pressure, climate change is forcing trees to cope, adapt, or die. Tree mortality may occur in response to pathogen infestations or result directly from hydraulic failure during acute and long-lasting droughts. However, trees may also cope with increasing abiotic and biotic stresses in the short-term, by metabolic responses involving an incredible array of chemicals, generally composed of constitutively produced and stress-induced secondary metabolites, for direct and indirect defense responses.

Furthermore, plants may adapt to climate change-driven stresses by long-term processes such as alterations in carbon allocation and growth rates, migration, natural selection of resistant genotypes, and phenotypic plasticity. Plant adjustments to environmental changes may also affect complex below and above ground multitrophic interactions within ecosystems. However, the processes controlling adjustments of plants to climate change are still poorly understood. Deciphering the mechanisms underpinning climate-resilience of trees is key to developing strategies for the amelioration of climate change effects and limiting future forest losses.

The special focus of this topic is the mechanistic and ecological understanding of processes behind responses of plants to abiotic and biotic stress, with extension to the effects on ecological interactions. Emphasis will be given to effects on stress-induced secondary compounds, mechanisms of volatile induction, processes triggering chemotypic or phenotypic change, and other metabolic and hydraulic responses that reduce or enhance stress susceptibility. Studies developing biomarkers for the selection of specific traits to cope with abiotic or biotic stresses are welcome as well as studies on plant associations with beneficial microbes that improve plant health and enhance stress-resistance. Studies addressing the genotypic variability and phenotypic plasticity of plants to produce susceptible and resistant chemotypes that can respond to climate change are desirable. Furthermore, because abiotic and biotic stresses negatively impact plant fitness and affect carbon availability for plant defense, studies on shifts of carbon allocation and translocation in respect to the biosynthesis of secondary metabolites are welcome.

This Research Topic welcomes original contributions that offer new and fundamental insights on plant interactions with the abiotic and biotic environments. We welcome studies on plant secondary metabolites involved in plant-atmosphere, plant-to-plant, plant-insect, and plant-microorganism interactions. ‘Omics’ studies (i.e., transcriptomics, proteomics, metabolomics) are strongly encouraged. We recommend empirical research based on field observations, laboratory or chamber experiments, and studies based on modeling approaches and elucidating mechanisms at molecular, cellular, or at organism levels. We welcome original research articles, short reports, mini-reviews, and comprehensive reviews, among others, that will provide a collection of recent advances in understanding the impacts of abiotic and biotic stresses to plants, and the mechanisms of plants to cope with or adapt to climate change.