Biology subjects

Suffert, F.

Publications and source records attributed to Suffert, F..

At least 19 recordsLinked to original sources

bioRxiv2025

Off-season sex in Zymoseptoria tritici: little room for late encounters

This study complements a substantial body of experimental work on the model fungal pathogen Zymoseptoria tritici by exploring marginal processes and conditions of sexual reproduction. Recent findings have shown that avirulent strains can engage in sexual reproduction on resistant host plants, even when they fail to cause visible symptoms during the biotrophic phase. The objective was here to examine the (de)coupling of various processes operating during the epidemic period (living plants) and the interepidemic period (crop residues). We assessed whether various encounter scenarios between parental strains, involving co-inoculations performed either simultaneously or sequentially on live and dead wheat plants, could result in successful mating. A two-year experiment accounted for the compatibility between wheat varieties (one carrying the resistance gene Stb16q, the other not) and the strains (virulent or avirulent), and the nature of the inoculum (blastospores or pycnidiospores). The intensity of sexual reproduction was assessed for each scenario through quantification of ascospore production, complemented by genotyping of offspring to confirm their parental origin. The main result is that a Z. tritici strain arriving late on dead host tissues can still mate with a compatible strain that previously colonized the plant, whereas sexual reproduction does not occur if both strains arrive after the plant has dried. Quantitative analysis suggests that although matings initiated by late encounters on wheat residues are possible, they contribute very little to the overall offspring population (< 2%). We discuss the epidemiological implications of this finding for disease management, highlighting both fundamental and applied questions it raises. HighlightsO_LIConfirms avirulent Z. tritici strains reproduce sexually on resistant wheat. C_LIO_LILate-arriving strains on dead tissues can mate with strains that infected earlier. C_LIO_LISex from such late encounters on wheat residues contributes little to offspring. C_LIO_LIFindings could impact understanding of pathogen lifecycle and disease control. C_LI

microbiology↗

bioRxiv2025

Uromyces plumbarius first reported on Oenothera lindheimeri in Europe with widespread distribution and association with the rust hyperparasite Sphaerellopsis sp.

The rust fungus Uromyces plumbarius Peck was reported in Europe for the first time on Oenothera lindheimeri (Engelm. & A. Gray) W.L. Wagner & Hoch (Lindheimers beeblossom), a highly popular ornamental plant widely cultivated since the 2000s. The fungus was found in 11 locations across France and two locations in the Netherlands. The identification was based on an analysis of morphological characteristics and 28S rDNA sequences. The pathogenicity was confirmed through reinoculation using fresh urediniospores. This represents the first record of U. plumbarius outside its native range in North America. Its widespread distribution in France appears to result from rapid dissemination, likely facilitated by the plant trade between nursery gardeners. The discovery of U. plumbarius was accompanied by the detection of the hyperparasitic fungus Sphaerellopsis sp. and fungivorous larvae of Mycodiplosis sp.--two native, non-specific natural enemies which may play a role in limiting the impact of rust infections.

microbiology↗

bioRxiv2024

Disruptive effect of rainfalls on the diurnal periodicity of airborne wheat rust spore under field conditions

Stripe rust and leaf rust, caused by Puccinia striiformis f. sp. tritici (Pst) and Puccinia triticina (Pt), respectively, are major threats to wheat production. Forecasting epidemics requires a deeper understanding of the mechanisms driving spore dispersal. Many studies have either employed field data for purely correlative approaches without incorporating established knowledge on physical mechanisms or, conversely, relied on specific physical approaches in controlled environments focusing on only a few mechanisms or factors. Little emphasis has been placed on holistic field-based studies, where wind and rain play crucial roles. This study fills that gap by attempting to unravel the processes by which rainfall affects airborne spore concentrations over a wheat canopy during active rust epidemics. Over more than two months, bi-hourly spore counts from Burkard traps were integrated with detailed meteorological data, revealing both seasonal and diurnal trends. Diurnal peaks in airborne spore concentrations, typically driven by cyclic changes in wind and humidity, were dramatically altered by rain. Rain events either amplified spore concentrations by up to 25-fold through rain-puff and/or depletes them via wash-out and wash-off. Rains events from the dataset were classified into categories with distinct impacts: precursor rains often trigger spore release, while follower (and prolonged rains) reduce airborne spore concentrations. Moreover, differences in the dispersal dynamics of Pst and Pt were observed, and some were linked to how humidity and wind influence spore clustering. These results provide valuable insights for a more integrated understanding of the effect of rain and in order to enhance forecasting models.

pathology↗

bioRxiv2023

Estimating the frequency of virulence against an Stb gene in Zymoseptoria tritici populations by bulk phenotyping on checkerboard microcanopies of wheat NILs

Monitoring virulent strains within fungal pathogen populations is crucial to improve host resistance deployment strategies. Such monitoring increasingly involves field pathogenomics studies of molecular polymorphisms in genomes based on high-throughput screening technologies. However, it is not always straightforward to predict virulence phenotypes from these polymorphisms and in planta phenotyping remains necessary. We developed a method for bulk phenotyping on checkerboard microcanopies of wheat near-isogenic lines (BPC) for estimating the frequency of virulence against an Stb gene in populations of Zymoseptoria tritici, the causal agent of Septoria tritici blotch in wheat, without the need for strain-by-strain phenotyping. Our method involves the uniform inoculation of a microcanopy of two wheat lines - one with the resistance gene and the other without it - with a multi-strain cocktail representative of the population to be characterized, followed by the differential quantification of infection points (lesions). Using Stb16q, a resistance gene that has recently broken down in Europe, we found a robust correlation between the ratio of the mean number of lesions on each wheat line and the frequency of virulent strains in the inoculum. Using pairs of virulent and avirulent strains, and synthetic populations consisting of 10 virulent strains and 10 avirulent strains mixed in different proportions, we validated the principle of the method and established standard curves at virulence frequencies close to those observed in natural conditions. We discuss the potential of this method for virulence monitoring in combination with recently developed molecular methods.

microbiology↗

bioRxiv2023

Can higher aggressiveness effectively compensate for a virulence deficiency in plant pathogen? A case study of Puccinia triticina's fitness evolution in a diversified varietal landscape

Plant resistances impose strong selective pressure on plant pathogen populations through the deployment of resistance genes, which leads to the emergence of new virulences. The pathogen adaptation also involves other parasitic fitness traits, especially aggressiveness components. A previous study on Puccinia triticina, the causal agent of wheat leaf rust, revealed that the distribution frequency of virulences in the French pathogen population cannot be fully explained by the major resistance genes deployed in the landscape. From 2012 to 2015, two dominant pathotypes (distinguished by their combination of virulences) were equally frequent despite the theoretical advantage conferred to one pathotype (166 317 0) by its virulence to Lr3, frequent in the cultivated landscape, whereas the other (106 314 0) is avirulent to this gene. To explain this apparent contradiction, we assessed three components of aggressiveness -- infection efficiency, latency period and sporulation capacity -- for 23 isolates representative of the most frequent genotype within each pathotype (106 314 0-G2 and 166 317 0-G1, identified by their combination of microsatellite markers). We tested these isolates on seedlings of Michigan Amber, a naive wheat cultivar that has never been grown in the landscape, Apache, a neutral cultivar with no selection effect on the landscape-pathotype pattern, and several cultivars that were frequently grown. We found that 106 314 0-G2 was more aggressive than 166 317 0-G1, with a consistency for the three components of aggressiveness. Our results show that aggressiveness plays a significant role in driving evolution in pathogen populations by acting as a selective advantage, even offsetting the disadvantage of lacking virulence towards a major Lr gene. Higher aggressiveness represents a competitive advantage that is likely even more pronounced when exhibited at the landscape scale as the expression of its multiple components is amplified by the polycyclic nature of epidemics.

plant biology↗

bioRxiv2022

A thousand-genome panel retraces the global spread and climatic adaptation of a major crop pathogen

Human activity impacts the evolutionary trajectories of many species worldwide. Global trade of agricultural goods contributes to the dispersal of pathogens reshaping their genetic makeup and providing opportunities for virulence gains. Understanding how pathogens surmount control strategies and cope with new climates is crucial to predicting the future impact of crop pathogens. Here, we address this by assembling a global thousand-genome panel of Zymoseptoria tritici, a major fungal pathogen of wheat reported in all production areas worldwide. We identify the global invasion routes and ongoing genetic exchange of the pathogen among wheat-growing regions. We find that the global expansion was accompanied by increased activity of transposable elements and weakened genomic defenses. Finally, we find significant standing variation for adaptation to new climates encountered during the global spread. Our work shows how large population genomic panels enable deep insights into the evolutionary trajectory of a major crop pathogen.

genomics↗

bioRxiv2022

Is virulence phenotype evolution driven exclusively by Lr gene deployment in French Puccinia triticina populations?

Puccinia triticina is a highly damaging wheat pathogen. The efficacy of leaf rust control by genetic resistance is mitigated by the adaptive capacity of the pathogen, expressed as changes in its virulence combinations (pathotypes). An extensive P. triticina population survey has been carried out in France over the last 30 years, describing the evolution dynamics of this pathogen in response to cultivar deployment. We analyzed the dataset for the 2006-2016 period to determine the relationship between the Lr genes in the cultivars and virulence in the pathotypes. Rust populations were dominated by a small number of pathotypes, with variations in most of the virulence frequencies related to the corresponding Lr gene frequencies in the cultivated landscape. Furthermore, the emergence and spread of a new virulence matched the introduction and use of the corresponding Lr gene (Lr28), confirming that the deployment of qualitative resistance genes is an essential driver of evolution in P. triticina populations. However, PCA revealed that certain pathotype-cultivar associations cannot be explained solely by the distribution of Lr genes in the landscape. This conclusion is supported by the predominance of a few pathotypes on some cultivars, with the persistence of several other compatible pathotypes at low frequencies. Specific interactions are not, therefore, sufficient to explain the distribution of virulence in rust populations. Our findings suggest that aggressiveness is a driver of changes in pathotype frequencies. Accordingly, the hypothesis of "dual selection", based on both qualitative and quantitative interactions between P. triticina populations and bread wheat cultivars, is favored.

microbiology↗

bioRxiv2022

How large and diverse are field populations of fungal plant pathogens? The case of Zymoseptoria tritici

Pathogen populations differ in the amount of genetic diversity they contain. Populations carrying higher genetic diversity are thought to have a greater evolutionary potential than populations carrying less diversity. We used published studies to estimate the range of values associated with two critical components of genetic diversity, the number of unique pathogen genotypes and the number of spores produced during an epidemic, for the septoria tritici blotch pathogen Zymoseptoria tritici. We found that wheat fields experiencing typical levels of infection are likely to carry between 3.2 and 14.9 million pathogen genotypes per hectare and produce at least 2.3 to 10.5 trillion pycnidiospores per hectare. Given the experimentally derived mutation rate of 3 x 10-10 substitutions per site per cell division, we estimate that between 28 and 130 million pathogen spores carrying adaptive mutations to counteract fungicides and resistant cultivars will be produced per hectare during a growing season. This suggests that most of the adaptive mutations that have been observed in Z. tritici populations can emerge through local selection from standing genetic variation that already exists within each field. The consequences of these findings for disease management strategies are discussed.

microbiology↗

bioRxiv2022

Multiple scenarios for sexual crosses in the fungal pathogen Zymoseptoria tritici on wheat residues: potential consequences for virulence gene transmission

Little is known about the impact of host immunity on sexual reproduction in fungal pathogens. In particular, it is unclear whether crossing requires both sexual partners to infect living plant tissues. We addressed this issue in a three-year experiment investigating different scenarios of Zymoseptoria tritici crosses on wheat according to the virulence ( vir) or avirulence ( avr) of the parents against a qualitative resistance gene. Co-inoculations ( vir x vir, avr x vir, avr x avr) and single inoculations were performed on a cultivar carrying the resistance gene (Cellule) and a susceptible cultivar (Apache), in the greenhouse. We assessed the intensity of asexual multiplication by scoring disease severity, and the intensity of sexual reproduction by counting the ascospores discharged from wheat residues. As expected, disease severity was more intense on Cellule for vir x vir co-inoculations than for avr x vir co-inoculations, with no disease for avr x avr. However, all types of co-inoculation yielded sexual offspring, whether or not the parental strains caused plant symptoms. Parenthood was confirmed by genotyping (SSR markers), and the occurrence of crosses between (co-)inoculated and exogenous strains (other strains from the experiment, or from far away) was determined. We found that symptomatic asexual infection was not required for a strain to participate in sexual reproduction, and that avirulent strains could be maintained asymptomatically "on" or "in" leaf tissues of plants carrying the corresponding resistant gene for long enough to reproduce sexually. In two of the three years, the intensity of sexual reproduction did not differ significantly between the three types of co-inoculation in Cellule, suggesting that crosses involving avirulent strains are not anecdotal. We discuss the possible mechanisms explaining the maintenance of avirulence in Z. tritici populations and supporting the potential efficacy of cultivar mixtures for limiting resistance gene breakdown. HighlightsO_LIAvirulent Zymoseptoria tritici strains can reproduce sexually in wheat plants carrying the corresponding resistant gene. C_LIO_LISymptomatic infection of plant tissues is not essential for a strain to reproduce sexually. C_LIO_LIAvirulent strains can be maintained asymptomatically "on" or "in" leaf tissues of plants carrying the corresponding resistant gene for long enough to reproduce sexually. C_LIO_LICrosses of virulent strains with virulent and avirulent strains in a plant host carrying the corresponding resistance gene can produce offspring with similar population sizes. C_LIO_LISeveral possible scenarios for sexual crosses can explain the maintenance of avirulence in Zymoseptoria tritici populations evolving in a wheat canopy, particular in cultivar mixtures. C_LI

microbiology↗

bioRxiv2022

NGS data reveals the phyllosphere microbiome of wheat plants infected by the fungal pathogen Zymoseptoria tritici

The fungal pathogen Zymoseptoria tritici is the causal agent of Septoria tritici blotch (STB), a major wheat disease in Western Europe. Microorganisms inhabiting wheat leaves might act as beneficial, biocontrol or facilitating agents that could limit or stimulate the development of Z. tritici. Improving our understanding of microbial communities in the wheat phyllosphere would lead to new insights into STB management. This resource announcement provides fungal and bacterial metabarcoding datasets obtained by sampling wheat leaves differing in the presence of symptoms caused by Z. tritici. Tissues were sampled from three wheat commercial varieties on three sampling dates during a cropping season. Weeds around wheat fields were sampled as well. In total, more than 450 leaf samples were collected. The pathogen Z. tritici was quantified using qPCR. We provide the raw metabarcoding datasets, the Amplicon Sequence Variant (ASV) tables obtained after bioinformatic processing, the metadata associated to each sample (sampling date, wheat variety and tissue health condition), a preliminary descriptive analysis of the data, and the code used for bioinformatic and descriptive statistical analysis.

microbiology↗

bioRxiv2022

Does the impact of cultivar mixtures on virulence dynamics in Zymoseptoria tritici populations persist after interseason sexual reproduction?

This study follows on from a previous study showing that binary mixtures of wheat cultivars affect the evolution of Zymoseptoria tritici populations within a field epidemic from the beginning (t1) to the end (t2) of a growing season. Here, we focused on the impact of interseason sexual reproduction on this evolution. We studied mixtures of susceptible and resistant cultivars (carrying Stb16q, a recently broken-down resistance gene) in proportions of 0.25, 0.5 and 0.75, and their pure stands. We determined the virulence status of 1440 ascospore-derived strains collected from residues of each cultivar by phenotyping on seedlings. Virulence frequencies were lower in mixtures than in pure stands of the resistant cultivar, as at t2, revealing that the impact of mixtures persisted until the beginning of the next epidemic (t3). The frequency of virulence was lower in the offspring population on the susceptible cultivar and, more surprisingly, the frequency of avirulence on the resistant cultivar increased after sexual reproduction. Our findings highlight two epidemiological processes in mixtures: selection within the local pathogen population between t1 and t2 driven by asexual cross-contamination between cultivars (previous study) and sexual crosses between avirulent and virulent strains between t2 and t3 driven by changes in the probabilities of physical encounters (this study). Mixtures therefore appear to be a promising strategy for the deployment of qualitative resistances, not only to limit the intensity of Septoria tritici blotch epidemics, but also to reduce the erosion of resistances by managing evolution of the pathogen population at a pluriannual scale.

ecology↗

bioRxiv2021

Measuring splash-dispersal of a major wheat pathogen in the field

Capacity for dispersal is a fundamental fitness component of plant pathogens. Empirical characterization of plant pathogen dispersal is of prime importance for understanding how plant pathogen populations change in time and space. We measured dispersal of Zymoseptoria tritici in natural environment. Primary disease gradients were produced by rain-splash driven dispersal and subsequent transmission via asexual pycnidiospores from infected source. To achieve this, we inoculated field plots of wheat (Triticum aestivum) with two distinct Z. tritici strains and a 50/50 mixture of the two strains. We measured effective dispersal of the Z. tritici population based on pycnidia counts using automated image analysis. The data were analyzed using a spatially-explicit mathematical model that takes into account the spatial extent of the source. We employed robust bootstrapping methods for statistical testing and adopted a two-dimensional hypotheses test based on the kernel density estimation of the bootstrap distribution of parameter values. Genotyping of re-isolated pathogen strains with strain-specific PCR-reaction further confirmed the conclusions drawn from the phenotypic data. The methodology presented here can be applied to other plant pathosystems. We achieved the first estimates of the dispersal kernel of the pathogen in field conditions. The characteristic spatial scale of dispersal is tens of centimeters - consistent with previous studies in controlled conditions. Our estimation of the dispersal kernel can be used to parameterize epidemiological models that describe spatial-temporal disease dynamics within individual wheat fields. The results have the potential to inform spatially targeted control of crop diseases in the context of precision agriculture.

plant biology↗

bioRxiv2021

Synergy of culture-dependent molecular identification and whole-community metabarcode sequencing for characterizing the microbiota of arable crop residues

This study is the first to compare culture-dependent (strain isolation plus molecular identification) and culture-independent (whole-community metabarcode sequencing) approaches for characterizing the microbiota of crop residues. We investigated the diversity of fungal and bacterial communities in wheat and oilseed rape residues, using two different culture-dependent strategies to cover the maximum diversity for each kingdom: broad substrate sampling coupled with low-throughput isolation and diversity analysis for fungi, and reduced substrate sampling coupled with high-throughput isolation and diversity analysis for bacteria. The proportion of cultivable microorganisms was neither as low as the 1% paradigm long associated with the rhizosphere microflora, nor as high as the 50% sometimes reported for the phyllosphere microflora. It was, thus, intermediate between the values for soil and plants. This finding is consistent with residues being considered to constitute an ecotone, at the interface between soil and phyllosphere. Isolation and metabarcoding provided consistent complementary information: they revealed close community profiles, leading to the identification of several common and specific amplicon sequence variants (ASVs). The power of the culture-independent approach was thus confirmed. By contrast the culture-dependent approach was less weak than anticipated. Firstly, it provided complementary information about microbial diversity, with several ASVs not retrieved by metabarcoding being identified after isolation in the community-based culture collection. Secondly, this approach made it possible to preserve and test different taxa either individually or after the creation of synthetic communities, for deciphering the ecological functions of communities beyond merely descriptive aspects.

microbiology↗

bioRxiv2021

'Phytopathological strolls' in the dual context of COVID-19 lockdown and IYPH2020: transforming constraints into an opportunity for public education about plant pathogens

The experience presented here relates to 2020, a particularly timely year for plant disease-related communication ( International Year of Plant Health IYPH2020), but also a unique year because of the COVID-19 pandemic. Our goal was to illustrate the diversity and beauty of fungal plant pathogens through a naturalist approach that could be followed by any amateur. We achieved this end through phytopathological strolls, in which we observed and determined the origin of symptoms on diseased plants found in our garden, in the local streets, in nearby open spaces, and sharing this matter with a broad public. The lockdown imposed in France created an additional motivation to take up the challenge, and to involve our children, even under strong constraints, such as movement restrictions. We observed and described fungal pathogens through hundreds of photographs, shared our findings with a large audience on Twitter, and received feedback. The material used was deliberately simple and transportable: a digital reflex camera, an old microscope, a mobile phone, some books and an Internet connexion. Between March 17, 2020 and June 20, 2021 we found 196 plant pathogens, including 97 rusts, 27 powdery mildews and 28 septoria-like diseases. We discuss here the importance of promoting searches for plant pathogens, their description and conservation, through a combination of classical approaches and digital tools in tune with the times, such as Twitter, by treating pathogen identification like a detective game and, more surprisingly, by making use of the addictive nature of collection approaches, drawing a parallel with Pokemon Go.

microbiology↗

bioRxiv2020

Life story of Tunisian durum wheat landraces revealed by their genetic and phenotypic diversity

Durum wheat (Triticum turgidum L. subsp. durum) landraces represent a prominent genetic resource for Mediterranean farming systems and breeding programs. Fourteen landraces sampled in Tunisia were genotyped with 9 microsatellite markers and characterized with 15 morphological descriptors, including resistance to the fungal disease Septoria tritici blotch (STB). The genetic diversity, nearly was as important within landraces populations (45%) than between populations (54%). It was structured in seven genetic groups and was only partly explained by the variety name or the locality of origin. Populations were also greatly diversified phenotypically (Shannon-Weaver H=0.54) with traits related to spike and awn colours being the most diversified. Resistance to STB was either qualitative in two populations or with varying degrees of quantitative resistance in the others. A Pst-Fst comparison indicate a local adaptation of the populations. Overall, the genetic structure of Tunisian durum wheat landraces revealed a complex selection trajectory and seed exchanges between farmers.

plant biology↗

bioRxiv2020

First report of the sexual stage of the flax pathogen Mycosphaerella linicola in France and its impact on pasmo epidemiology

We performed a three-year field survey in France to characterize the dynamics of sexual reproduction in Mycosphaerella linicola, the causal agent of pasmo, during the interepidemic period. Cohorts of fruiting bodies were sampled from linseed straw during the autumn and winter and carefully observed, focusing on pseudothecia, asci and ascospores. A sequence of experimental steps corresponding to Kochs postulates confirmed in July 2014, for the first time in France and continental Europe, the widespread presence of the sexual stage of M. linicola in plant host tissues. The developmental dynamics of pseudothecia on straw, expressed as the change over time in the percentage of mature pseudothecia, was similar in all three years. Pseudothecia appeared in late summer, with peak maturity reached in October. A temporal shift, thought to be due to early autumn rainfall, was highlighted in one of the three years. These observations suggest that sexual reproduction plays a significant role in the epidemiology of pasmo in France. A resurgence of M. linicola infections in spring flax is thought to have occurred in recent years, due to the increase in the area under flax. The presence of the sexual stage of this pathogen probably increased the quantitative impact of residues of winter linseed (used for oil) and flax straw (left on the soil for retting and used for fibers) as an interepidemic brown bridge. This case study highlights how certain parts of a disease cycle, in this case the sexual phase, can become crucial due to changes in production conditions.

pathology↗

bioRxiv2020

Impact of a resistance gene against a fungal pathogen on the plant host residue microbiome: the case of the Leptosphaeria maculans-Brassica napus pathosystem

Oilseed rape residues are a crucial determinant of stem canker epidemiology, as they support the sexual reproduction of the fungal pathogen Leptosphaeria maculans. The aim of this study was to characterise the impact of a resistance gene against L. maculans infection on residue microbial communities and to identify micro-organisms interacting with this pathogen during residue degradation. We used near-isogenic lines to obtain healthy and infected host plants. The microbiome associated with the two types of plant residues was characterised by metabarcoding. A combination of linear discriminant analysis and ecological network analysis was used to compare the microbial communities and to identify micro-organisms interacting with L. maculans. Fungal community structure differed between the two lines at harvest, but not subsequently, suggesting that the presence/absence of the resistance gene influences the microbiome at the base of the stem whilst the plant is alive, but that this does not necessarily lead to differential colonisation of the residues by fungi. Direct interactions with other members of the community involved many fungal and bacterial ASVs (amplicon sequence variants). L. maculans appeared to play a minor role in networks, whereas one ASV affiliated to Plenodomus biglobosus (synonym Leptosphaeria biglobosa) from the Leptosphaeria species complex may be considered a keystone taxon in the networks at harvest. This approach could be used to identify and promote micro-organisms with beneficial effects against residue-borne pathogens, and more broadly, to decipher the complex interactions between multi-species pathosystems and other microbial components in crop residues.

microbiology↗

bioRxiv2019

Patterns of thermal adaptation in a worldwide plant pathogen: local diversity and plasticity reveal two-tier dynamics

O_LIPlant pathogen populations inhabit patchy environments with contrasting, variable thermal conditions. We investigated the diversity of thermal responses in populations sampled over contrasting spatiotemporal scales, to improve our understanding of their dynamics of adaptation to local conditions. C_LIO_LISamples of natural populations of the wheat pathogen Zymoseptoria tritici were collected from sites within the Euro-Mediterranean region subject to a broad range of environmental conditions. We tested for local adaptation, by accounting for the diversity of responses at the individual and population levels on the basis of key thermal performance curve parameters and thermotype (groups of individuals with similar thermal responses) composition. C_LIO_LIThe characterisation of phenotypic responses and genotypic structure revealed: (i) a high degree of individual plasticity and variation in sensitivity to temperature conditions across spatiotemporal scales and populations; (ii) geographic adaptation to local mean temperature conditions, with major alterations due to seasonal patterns over the wheat-growing season. C_LIO_LIThe seasonal shifts in functional composition suggest that populations are locally structured by selection, contributing to shape adaptation patterns. Further studies combining selection experiments and modelling are required to determine how functional group selection drives population dynamics and adaptive potential in response to thermal heterogeneity. C_LI

ecology↗