Biology subjects

Moralejo, E.

Publications and source records attributed to Moralejo, E..

5 recordsLinked to original sources

bioRxiv2026

Hidden biotic stress alters climate sensitivity in woody plants

Chronic infection by vascular pathogens is conventionally expected to severely constrain host biomass accumulation, yet empirical evidence from long-lived woody plants remains inconsistent. We investigated the long-term impacts of Xylella fastidiosa colonization on the radial growth and climate sensitivity of adult Mediterranean almond trees (Prunus dulcis), aiming to resolve how persistent vascular infections modulate tree performance and resilience under a changing climate. We coupled high-resolution dendrochronological analysis with a novel, ring-resolved molecular reconstruction of individual infection histories across 706 annual rings. This hindcasting approach allowed for the retrospective identification of precise colonization dates, bacterial loads (Ct values), and pathogen subspecies (subsp. fastidiosa vs. subsp. multiplex). Growth-climate relationships were modelled using standardized ring-width indices (RWI) against a crop-weighted water deficit index (CWDi). Intra-host colonization followed a steep radial gradient, with active bacterial abundance concentrated in newly formed, functional outer xylem. Surprisingly, chronic infection did not trigger a sustained reduction in baseline annual ring width. Instead, pathogens fundamentally reshaped climate-growth sensitivity. Hosts infected by subsp. fastidiosa maintained high plastic growth tracking during wet years, whereas this capacity was significantly attenuated in those harbouring subsp. multiplex. Despite the absence of a chronic signal in trunk radial growth, vascular impairment was tightly associated with severe retrograde canopy dieback. Our findings indicate that chronic infection by X. fastidiosa can act as a latent biotic stressor, altering host physiological sensitivity to environmental fluctuations without directly suppressing baseline stem growth. This pattern is consistent with the marked temporal decoupling between spring cambial activity and late-summer bacterial proliferation, together with progressive vascular dysfunction leading to severe canopy dieback. These results suggest that current abiotic-centred frameworks of drought-induced decline may underestimate the contribution of cryptic vascular pathogens to vegetation mortality under intensifying climate change.

plant biology↗

bioRxiv2024

High-resolution climate data reveals increased risk of Pierce's Disease for grapevines worldwide

Range shifts in plant disease distributions are sensitive to scaling processes, but few crop case studies have included these predictions under climate change. High-quality wines are increasingly produced in topographically heterogeneous river valleys, whereby disease models that capture steep relief gradients become especially relevant. Here we show how non-linear epidemiological models more accurately reflect the threat of an emerging grapevine pathogen in areas with significant spatial gradients. By comparing the results of simulations using climate data with different spatial resolutions, we identify an increased risk of Pierces disease (PD), caused by the vector-borne bacterium Xylella fastidiosa, in wine regions globally. Over 100,000 vine presence records worldwide were analysed with respect to their closer risk-grid cell, observing an increase from 21.8% to 41.2% of the area at risk in European vineyards, from 5.6% to 47.2% in South Africa and to a lesser extent in other wine-growing regions. This general trend has been preceded by an accelerating rate of increase in risk within wine-growing areas. Our analysis demonstrates the importance of microclimatic conditions, highlighting previously unresolved risk zones in areas close to rivers and valleys, and the insufficiency of lower resolution data sets to capture complex climatic variations.

ecology↗

bioRxiv2023

Contrasting Patterns of Pierce's Disease Risk in European Vineyards Under Global Warming

Pierces Disease (PD) is a vector-borne disease caused by the bacterium Xylella fastidiosa, which poses a significant threat to grapevines worldwide. Despite its importance, the risk of future PD establishment in Europe remains unclear due to previous incomplete methodologies followed by conflicting results. Here we present a comprehensive approach considering the compound effect of climate change on the pathosystem. Within the general trend of progressively increasing PD risk, we identified the +3{o}C scenario as a turning point for potential spreading beyond Mediterranean regions, representing a serious risk for French and Italian viticulture. Our innovative methodology reveals PD risk as a multi-factor multi-scale process, showing contrasting spatial patterns and different risk velocities across regions, as well as a high timing uncertainty. By overcoming previous limitations, our findings contribute to a better understanding of the potential spread of PD in Europe, supporting informed decision-making for disease management and prevention.

ecology↗

bioRxiv2022

A compartmental model for Xylella fastidiosa diseases with explicit vector seasonal dynamics

The bacterium Xylella fastidiosa (Xf) is mainly transmitted by the spittlebug, Philaenus spumarius, in Europe, where it has caused significant economic damage to olive and almond trees. Understanding the factors that determine disease dynamics in pathosystems that share similarities can help design control strategies focused on minimizing transmission chains. Here we introduce a compartmental model for Xf-caused diseases in Europe that accounts for the main relevant epidemiological processes, including the seasonal dynamics of P. spumarius. The model was confronted with epidemiological data from the two major outbreaks of Xf in Europe, the olive quick disease syndrome (OQDS) in Apulia, Italy, caused by the subspecies pauca, and the almond leaf scorch disease (ALSD) in Majorca, Spain, caused by subspecies multiplex and fastidiosa. Using a Bayesian inference framework, we show how the model successfully reproduces the general field data in both diseases. In a global sensitivity analysis, the vector-plant and plant-vector transmission rates, together with the vector removal rate, were the most influential parameters in determining the time of the infected host population peak, the incidence peak and the final number of dead hosts. We also used our model to check different vector-based control strategies, showing that a joint strategy focused on increasing the rate of vector removal while lowering the number of annual newborn vectors is optimal for disease control.

plant biology↗

bioRxiv2022

Global predictions for the risk of establishment of Pierce's disease of grapevines

The vector-borne bacterium Xylella fastidiosa is responsible for Pierces disease (PD), a lethal grapevine illness that originated in the Americas. The international plant trade is expanding the geographic range of this pathogen, posing a new threat to viticulture worldwide. To assess the potential incidence of PD, we have built a dynamic epidemiological model based on the response of 36-grapevine varieties to the pathogen in inoculation assays and on the vectors distribution when this information is available. Key temperature-driven epidemiological processes, such as PD symptom development and recovery, are mechanistically modelled. Integrating into the model highresolution spatiotemporal climatic data from 1981 onward and different infectivity (R0) scenarios, we show how the main wine-producing areas thrive mostly in non-risk, transient, or epidemic-risk zones with potentially low growth rates in PD incidence. Epidemic-risk zones with moderate to high growth rates are currently marginal outside the United States. However, a global expansion of epidemic-risk zones coupled with small increments in the disease growth rate is projected for 2050. Our study globally downscales the risk of PD establishment while highlighting the importance of considering climate variability, vector distribution and an invasive criterion in obtaining accurate risk maps to guide policy decision-making in plant health.

plant biology↗