Biology subjects

Deredec, A.

Publications and source records attributed to Deredec, A..

4 recordsLinked to original sources

bioRxiv2022

Preventing multiple resistance above all: new insights for managing fungal adaptation

Sustainable crop protection is crucial for food security, but is threatened by the adaptation of diverse, evolving pathogen population. Resistance can be managed by maximizing selection pressure diversity, by dose variation and the spatial and temporal combination of active ingredients. We explored the interplay between operational drivers for maximizing management strategy sustainability relative to the resistance status of fungal populations. We applied an experimental evolution approach to three artificial populations of an economically important wheat pathogen, Zymoseptoria tritici, differing in initial resistance status. We revealed that diversified selection pressure limited the selection of resistance in naive populations and those with low frequencies of single. Increasing the number of modes of action delayed resistance development most effectively -- ahead of increasing the number of fungicides, fungicide choice based on resistance risk and temporal variation in fungicide exposure -- but favored generalism in the evolved populations. However, the prior presence of multiple resistant resistant isolates and their subsequent selection in populations overrode the effects of diversity in management strategies, incidentally invalidating any universal ranking. Initial resistance composition must therefore be considered specifically in sustainable resistance management, to address real-world field situation. Abbreviated summaryExperimental evolution is a relevant tool for exploring the determinants of antifungal adaptation in fungi. Here, using the model species Z. tritici and two fungicidal modes of action associated with contrasting resistance risks, we have demonstrated that initial population composition, and in particular the presence of multiple resistance, represents the main determinant of adaptive trajectories. Originality-Significance StatementPesticides are part of microbe environment in agricultural systems and may select for resistance. This adaptation of pathogens is a burden for plant health. Using an original multicriteria assessment and experimental evolution, we revealed that multi-fungicide use, selecting for multiple resistance, trumped any other driver of selection, invalidating any universal ranking of management strategies, a dispute extensively illustrated in literature and still inconclusive, especially in agriculture. This outcome refocuses the debate on population diversity and evolution rather than on the intrinsic properties of strategies, as mostly acclaimed in literature. From a practical point of view, our results highlight the importance of considering local population composition when recommending spraying programs. This practice is currently not generalized in agriculture but may be timely to effectively delay resistance evolution and reduce pesticide load in agricultural systems, a growing social demand, since resistance monitoring at relatively fine spatial scales and at low frequency may become commonplace in a near future with the rise of new molecular biology technologies

evolutionary biology↗

bioRxiv2021

Why do fungicide mixtures delay the evolution of resistance? An experimental evolutionary approach

Pesticide resistance poses a critical threat to agriculture, human health and biodiversity. Mixtures of fungicides are recommended and widely used in resistance management strategies. However, the components of the efficiency of such mixtures remain unclear. We performed an experimental evolution study on the fungal pathogen Z. tritici, to determine how mixtures managed resistance. We compared the effect of the continuous use of single active ingredients to that of mixtures, at the minimal dose providing full control of the disease, which we refer to as the "efficient" dose. We found that the performance of efficient-dose mixtures against an initially susceptible population depended strongly on the components of the mixture. Such mixtures were either as durable as the best mixture component used alone, or worse than all components used alone. Moreover, efficient-dose mixture regimes probably select for generalist resistance profiles as a result of the combination of selection pressures exerted by the various components and their lower doses. Our results indicate that mixtures should not be considered a universal strategy. Experimental evaluations of specificities for the pathogens targeted, their interactions with fungicides and the interactions between fungicides are crucial for the design of sustainable resistance management strategies.

evolutionary biology↗

bioRxiv2021

I alternate therefore I generalize: how the intrinsic resistance risk of fungicides counterbalances their durability

The evolution of resistance to pesticides is a major burden in agriculture. Resistance management involves maximizing selection pressure heterogeneity, particularly by combining active ingredients with different modes of action. We tested the hypothesis that alternation may delay the build-up of resistance not only by spreading selection pressure over longer periods, but also by decreasing the rate of evolution of resistance to alternated fungicides, by applying an experimental evolution approach to the economically important crop pathogen Zymoseptoria tritici. Our results show that alternation is either neutral or slows the overall resistance evolution rate, relative to continuous fungicide use, but results in higher levels of generalism in evolved lines. We demonstrate that the nature of the fungicides, and therefore their relative intrinsic risk of resistance may underly this trade-off, more so than the number of fungicides and the rhythm of alternation. This trade-off is also dynamic over the course of resistance evolution. These findings open up new possibilities for tailoring resistance management effectively while optimizing interplay between alternation components.

evolutionary biology↗

bioRxiv2017

Self-limiting population genetic control with sex-linked genome editors

In male heterogametic species the Y chromosome is transmitted solely from fathers to sons, and is selected for based only on its impacts on male fitness. This fact can be exploited to develop efficient pest control strategies that use Y-linked editors to disrupt the fitness of female descendants. In simple \"strategic\" population models we show that Y-linked editors can be substantially more efficient than other self-limiting strategies and, while not as efficient as gene drive approaches, are expected to have less impact on non-target populations with which there is some gene flow. Efficiency can be further augmented by simultaneously releasing an autosomal X-shredder construct, in either the same or different males. Y-linked editors may be attractive option to consider when efficient control of a species is desired in some locales but not others.

synthetic biology↗