New Phytologist

Journal: New Phytologist

Abbreviation

New Phytol.

Publisher

Wiley-Blackwell

ISSN

0028-646X
1469-8137

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Publications1 - 10 of 164

A glimmer of hope – ash genotypes with increased resistance to ash dieback pathogen show cross-resistance to emerald ash borer
Gossner, Martin M.; Perret-Gentil, Anouchka; Britt, Elisabeth; et al. (2023)
New Phytologist
Plants rely on cross-resistance traits to defend against multiple, phylogenetically distinct enemies. These traits are often the result of long co-evolutionary histories. Biological invasions can force naïve plants to cope with novel, coincident pests, and pathogens. For example, European ash (Fraxinus excelsior) is substantially threatened by the emerald ash borer (EAB), Agrilus planipennis, a wood-boring beetle, and the ash dieback (ADB) pathogen, Hymenoscyphus fraxineus. Yet, plant cross-resistance traits against novel enemies are poorly explored and it is unknown whether naïve ash trees can defend against novel enemy complexes via cross-resistance mechanisms. To gain mechanistic insights, we quantified EAB performance on grafted replicates of ash genotypes varying in ADB resistance and characterized ash phloem chemistry with targeted and untargeted metabolomics. Emerald ash borer performed better on ADB-susceptible than on ADB-resistant genotypes. Moreover, changes in EAB performance aligned with differences in phloem chemical profiles between ADB-susceptible and ADB-resistant genotypes. We show that intraspecific variation in phloem chemistry in European ash can confer increased cross-resistance to invasive antagonists from different taxonomic kingdoms. Our study suggests that promotion of ADB-resistant ash genotypes may simultaneously help to control the ADB disease and reduce EAB-caused ash losses, which may be critical for the long-term stability of this keystone tree species.
Legacy effects of premature defoliation in response to an extreme drought event modulate phytochemical profiles with subtle consequences for leaf herbivory in European beech
Eisenring, Michael; Gessler, Arthur; Frei, Esther R.; et al. (2024)
New Phytologist
Extreme droughts can have long-lasting effects on forest community dynamics and species interactions. Yet, our understanding of how drought legacy modulates ecological relationships is just unfolding. We tested the hypothesis that leaf chemistry and herbivory show long-term responses to premature defoliation caused by an extreme drought event in European beech (Fagus sylvatica L.). For two consecutive years after the extreme European summer drought in 2018, we collected leaves from the upper and lower canopy of adjacently growing drought-stressed and unstressed trees. Leaf chemistry was analyzed and leaf damage by different herbivore-feeding guilds was quantified. We found that drought had lasting impacts on leaf nutrients and on specialized metabolomic profiles. However, drought did not affect the primary metabolome. Drought-related phytochemical changes affected damage of leaf-chewing herbivores whereas damage caused by other herbivore-feeding guilds was largely unaffected. Drought legacy effects on phytochemistry and herbivory were often weaker than between-year or between-canopy strata variability. Our findings suggest that a single extreme drought event bears the potential to long-lastingly affect tree-herbivore interactions. Drought legacy effects likely become more important in modulating tree-herbivore interactions since drought frequency and severity are projected to globally increase in the coming decades.
Tree water uptake patterns across the globe
Bachofen, Christoph; Tumber-Dávila, Shersingh Joseph; Mackay, D. Scott; et al. (2024)
New Phytologist
Plant water uptake from the soil is a crucial element of the global hydrological cycle and essential for vegetation drought resilience. Yet, knowledge of how the distribution of water uptake depth (WUD) varies across species, climates, and seasons is scarce relative to our knowledge of aboveground plant functions. With a global literature review, we found that average WUD varied more among biomes than plant functional types (i.e. deciduous/evergreen broadleaves and conifers), illustrating the importance of the hydroclimate, especially precipitation seasonality, on WUD. By combining records of rooting depth with WUD, we observed a consistently deeper maximum rooting depth than WUD with the largest differences in arid regions - indicating that deep taproots act as lifelines while not contributing to the majority of water uptake. The most ubiquitous observation across the literature was that woody plants switch water sources to soil layers with the highest water availability within short timescales. Hence, seasonal shifts to deep soil layers occur across the globe when shallow soils are drying out, allowing continued transpiration and hydraulic safety. While there are still significant gaps in our understanding of WUD, the consistency across global ecosystems allows integration of existing knowledge into the next generation of vegetation process models.
Daytime stomatal regulation in mature temperate trees prioritizes stem rehydration at night
Peters, Richard L.; Steppe, Kathy; Pappas, Christoforos; et al. (2023)
New Phytologist
Trees remain sufficiently hydrated during drought by closing stomata and reducing canopy conductance (Gc) in response to variations in atmospheric water demand and soil water availability. Thresholds that control the reduction of Gc are proposed to optimize hydraulic safety against carbon assimilation efficiency. However, the link between Gc and the ability of stem tissues to rehydrate at night remains unclear. We investigated whether species-specific Gc responses aim to prevent branch embolisms, or enable night-time stem rehydration, which is critical for turgor-dependent growth. For this, we used a unique combination of concurrent dendrometer, sap flow and leaf water potential measurements and collected branch-vulnerability curves of six common European tree species. Species-specific Gc reduction was weakly related to the water potentials at which 50% of branch xylem conductivity is lost (P50). Instead, we found a stronger relationship with stem rehydration. Species with a stronger Gc control were less effective at refilling stem-water storage as the soil dries, which appeared related to their xylem architecture. Our findings highlight the importance of stem rehydration for water-use regulation in mature trees, which likely relates to the maintenance of adequate stem turgor. We thus conclude that stem rehydration must complement the widely accepted safety–efficiency stomatal control paradigm.
Mycorrhizas improve nitrogen nutrition of Trifolium repens after 8 yr of selection under elevated atmospheric CO2 partial pressure
Gamper, Hannes; Hartwig, Ueli A.; Leuchtmann, Adrian (2005)
New Phytologist
How can we achieve durable disease resistance in agricultural ecosystems?
McDonald, Bruce (2010)
New Phytologist
Genome-environment association study suggests local adaptation to climate at the regional scale in Fagus sylvatica
Pluess, Andrea R.; Frank, Aline; Heiri, Caroline; et al. (2016)
New Phytologist
Finding the balance between open access to forest data while safeguarding the integrity of National Forest Inventory-derived information
Gessler, Arthur; Schaub, Marcus; Bose, Arun; et al. (2024)
New Phytologist
Integration of attractive and defensive phytochemicals is unlikely to constrain chemical diversification in a perennial herb
Thosteman, Hanna Eriksdotter; Eisen, Katherine; Petren, Hampus; et al. (2024)
New Phytologist
Diversification of plant chemical phenotypes is typically associated with spatially and temporally variable plant-insect interactions. Floral scent is often assumed to be the target of pollinator-mediated selection, whereas foliar compounds are considered targets of antagonist-mediated selection. However, floral and vegetative phytochemicals can be biosynthetically linked and may thus evolve as integrated phenotypes. Utilizing a common garden of 28 populations of the perennial herb Arabis alpina (Brassicaceae), we investigated integration within and among floral scent compounds and foliar defense compounds (both volatile compounds and tissue-bound glucosinolates). Within floral scent volatiles, foliar volatile compounds, and glucosinolates, phytochemicals were often positively correlated, and correlations were stronger within these groups than between them. Thus, we found no evidence of integration between compound groups indicating that these are free to evolve independently. Relative to self-compatible populations, self-incompatible populations experienced stronger correlations between floral scent compounds, and a trend toward lower integration between floral scent and foliar volatiles.
Our study serves as a rare test of integration of multiple, physiologically related plant traits that each are potential targets of insect-mediated selection. Our results suggest that independent evolutionary forces are likely to diversify different axes of plant chemistry without major constraints.
High nitrogen
Güsewell, Sabine (2005)
New Phytologist

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