Division of Biotechnology and Plant Health
PROTECT: Priming for Resistance Of Trees and its Effects on microbial CommuniTies
End: sep 2025
Start: oct 2021
To protect themselves from pests and pathogens, plants have evolved multi-layered resistance mechanisms that include both constitutive and inducible defenses. These defense mechanisms are not static, but are adaptive to environmental changes.
| Status | Active |
| Start - end date | 01.10.2021 - 30.09.2025 |
| Project manager | Melissa Magerøy |
| Division | Division of Biotechnology and Plant Health |
| Department | Molecular Plant Biology |
| Total budget | 12000000 |
| Funding source | Forskningsrådet (Research Council of Norway) |
Sensitizing of inducible defenses is an important adaptation that allows an organism to activate its defenses more quickly upon detecting a threat. In plants, this sensitization is called defense priming and is similar to immunological memory in animals. Epigenetic modifications is an important mechanism by which defense priming occurs. Plants also rely on beneficial microorganism to improve their stress tolerance and pathogen resistance. These symbiotic relationships both affect and can be affected by epigenetic changes to the plant genome.
In this project, we seek to better understand how defense priming of Norway spruce affects the establishment of beneficial microbial communities, and how these communities in turn affect spruce resistance to pests and pathogens. We will identify novel spruce priming chemicals that increase spruce resistance with minimal secondary effects, such as growth inhibition. We will also determine the effects of spruce defense priming on its microbiota diversity and the effects of microbiota diversity on spruce defense priming and resistance. Additionally, we will determine the effects of both defense priming and microbiota on the spruce epigenome, hormone signaling pathways, the accumulation of defensive molecules, and defense gene expression.
Knowledge gained from this project will deepen our understanding of the spruce holobiont (spruce and its microbiota) and help us to better assess the ecological implication of Norway spruce defense priming. Such knowledge is crucial if we are to utilize defense priming as an effective pest management strategy in forestry.
Publications in the project
Authors
Carl Gunnar Fossdal Paal Krokene Jorunn Elisabeth Olsen George Richard Strimbeck Marcos Viejo Igor A. Yakovlev Melissa MagerøyAbstract
No abstract has been registered
Abstract
• For more than 20 years, methyl jasmonate (MeJA) has been used to study inducible defenses in conifers and to increase tree resistance to pests and pathogens. Despite the numerous studies on the subject, no attempts have been made to summarize or quantify how MeJA affects resistance and growth in conifers. Here we present a quantitative meta-analysis of the effects of MeJA treatment on the conifer genera Pinus and Picea, two of the most economically and ecologically important tree genera in boreal, temperate, and alpine forests. • A literature search yielded 120 relevant papers. We summarized the key experimental methods used in these papers and performed a meta-analysis of how MeJA affects tree growth and resistance to pests and pathogens. • The results show that MeJA negatively affects tree growth, with an overall effect size of −0.63. The overall effect size of MeJA for tree resistance was −0.76, indicating that MeJA treatment significantly reduces tree damage caused by biotic stressors. • Although our meta-analysis shows that MeJA is effective in enhancing conifer defenses, there are still gaps in our understanding of the durability and ecological consequences of MeJA treatment. We provide suggestions for how future research should be conducted to address these gaps.
Authors
Melissa MagerøyAbstract
No abstract has been registered
Authors
Ngan Bao Huynh Paal Krokene Jorunn Elisabeth Olsen Taina Pennanen Adriana Puentes Vaida Sirgedaitė-Šėžienė Vytautas Čėsna Ieva Čėsnienė Melissa MagerøyAbstract
No abstract has been registered
Authors
Melissa MagerøyAbstract
No abstract has been registered
Authors
Ngan Bao HuynhAbstract
No abstract has been registered
Abstract
The large pine weevil (Hylobius abietis) is a major regeneration pest in commercial forestry. Pesticide application has historically been the preferred control method, but pesticides are now being phased out in several countries for environmental reasons. There is, thus, a need for alternative plant protection strategies. We applied methyl jasmonate (MeJA), salicylic acid (SA) or oxalic acid (OxA) on the stem of 2-year-old Norway spruce (Picea abies) plants to determine effects on inducible defenses and plant growth. Anatomical examination of stem cross-sections 9 weeks after application of 100 mM MeJA revealed massive formation of traumatic resin ducts and greatly reduced sapwood growth. Application of high concentrations of SA or OxA (500 and 200 mM, respectively) induced much weaker physiological responses than 100 mM MeJA. All three treatments reduced plant height growth significantly, but the reduction was larger for MeJA (~55%) than for SA and OxA (34-35%). Lower MeJA concentrations (5-50 mM) induced comparable traumatic resin duct formation as the high MeJA concentration but caused moderate (and non-significant) reductions in plant growth. Two-year-old spruce plants treated with 100 mM MeJA showed reduced mortality after exposure to pine weevils in the field, and this enhanced resistance-effect was statistically significant for three years after treatment.
Authors
Melissa MagerøyAbstract
No abstract has been registered
Authors
Melissa MagerøyAbstract
No abstract has been registered
Abstract
Purpose of Review Forestry in northern temperate and boreal regions relies heavily on conifers. Rapid climate change and associated increases in adverse growing conditions predispose conifers to pathogens and pests. The much longer generation time and presumably, therefore, lower adaptive capacity of conifers relative to their native or non-native biotic stressors may have devastating consequences. We provide an updated overview of conifer defences underlying pathogen and pest resistance and discuss how defence traits can be used in tree breeding and forest management to improve resistance. Recent Findings Breeding of more resilient and stress-resistant trees will benefit from new genomic tools, such as genotyping arrays with increased genomic coverage, which will aid in genomic and relationship-based selection strategies. However, to successfully increase the resilience of conifer forests, improved genetic materials from breeding programs must be combined with more flexible and site-specific adaptive forest management. Summary Successful breeding programs to improve conifer resistance to pathogens and pests provide hope as well as valuable lessons: with a coordinated and sustained effort, increased resistance can be achieved. However, mechanisms underlying resistance against one stressor, even if involving many genes, may not provide any protection against other sympatric stressors. To maintain the adaptive capacity of conifer forests, it is important to keep high genetic diversity in the tree breeding programs. Choosing forest management options that include diversification of tree-species and forest structure and are coupled with the use of genetically improved plants and assisted migration is a proactive measure to increase forest resistance and resilience to foreseen and unanticipated biotic stressors in a changing climate.
Abstract
No abstract has been registered
Authors
Melissa MagerøyAbstract
Epigenetic modification is an important mechanism that allows plants to rapidly adapt to changes in environment. This modification can provide long-term increased tolerance and resistance to abiotic and biotic stress and may even be transmittable to progeny. Knowledge on how epigenetic memory is established, maintained, triggered, and transmitted in plants with different evolutionary and life histories is important for understanding and utilizing epigenetic adaptation in plant protection. In this symposium, we welcome talks from those that provide insight into the molecular mechanism underlying epigenetic memory to those that present the practical aspects of implementing epigenetic adaptation in the field.
Authors
Melissa MagerøyAbstract
No abstract has been registered
Abstract
Defense priming, the sensitization of inducible defenses, has been extensively studied in annual angiosperms. However, we are just beginning to explore defense priming in woody, long-lived plants. The natural compound methyl jasmonate (MeJA) has been used for over 20 years to study spruce inducible defenses. Recently, it was discovered that MeJA not only directly induces defense, but also primes defense responses in spruce. Metabolite and transcriptional analyses of mature trees treated with MeJA and subsequently wounded showed that while terpenes accumulate at the wound site in a primed manner, terpene biosynthesis genes are directly induced by MeJA. Pathogen resistance (PR) genes, on the other hand, are primed. Sequencing of miRNAs suggests that miRNAs have a regulatory role in MeJA-induced defenses in spruce. Additionally, a detailed transcriptional time course of 2- year-old spruce treated with MeJA indicated that the RNA-directed DNA methylation (RdDM) pathway is involved in the establishment and maintenance of primed defenses. When comparing mechanisms of defense priming in spruce to those in Arabidopsis, it seems that many mechanisms are conserved. However, some aspects, such as jasmonic acid-salicylic acid crosstalk, may be different. Identifying these differences and how they affect forest species is important for practical application of defense priming in forest management.
Abstract
No abstract has been registered