Frédéric Suffert

• Plant disease epidemiologist
• French National Institute for Agriculture, Food, and Environment (INRAE)

CONTEXTE - De nombreuses études ont démontré que les mélanges variétaux limitent le développement des épidémies fongiques. IMPACT ET MÉCANISMES - Les mélanges ont un effet quantitatif sur la sévérité de septoriose du blé à l’échelle de la parcelle au cours d’une saison, et constituent une réponse efficace aux enjeux de performance agronomique. Les...

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 incor...

In an era marked by rapid global changes, the reinforcement and modernization of plant health surveillance systems have become imperative. Sixty-five scientists present here a research agenda for an enhanced and modernized plant health surveillance to anticipate and mitigate disease and pest emergence. Our approach integrates a wide range of scient...

Little is actually known about the impact of host immunity on sexual reproduction in Zymoseptoria tritici but also reciprocally about the impact of sexual reproduction on epidemiological processes and adaptive dynamics of pathogen populations driven by R-Avr interactions. An experiment investigating different scenarios of Z. tritici crosses on whea...

The management of Septoria tritici blotch (STB) caused by Zymoseptoria tritici increasingly relies on varietal resistance. However, the deployment of wheat cultivars across large cultivated areas lead to the emergence and change in virulence frequencies in pathogen populations and ultimately to the erosion of resistances. Understanding the dynamics...

Fungal plant pathogens pose significant threats to food security and are dominant components of global agroecosystems. Despite wide environmental distributions, many fungal populations are locally adapted to cultivated hosts, fungicide uses, and climatic conditions. Understanding the mechanisms through which pathogens overcome control measures and...

Septoria tritici blotch (STB) caused by Zymoseptoria tritici is a major foliar disease of wheat. Disease control is generally undertaken by application of fungicides and use of varieties carrying resistance genes (Stb genes). But these control methods can be quickly overstepped as they impose high selection pressure on the pathogen, especially when...

Compte rendu de la sortie mycologie organisée le 28 avril 2024 pour l’Association des Naturalistes des Yvelines (ANY ; https://www.siteany78.org/)

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 lea...

Monitoring virulent strains within pathogen populations is crucial to improve host resistance deployment strategies. Such monitoring increasingly involves field pathogenomics studies of molecular polymorphisms in pathogen genomes based on high‐throughput screening technologies. However, it is not always straightforward to predict virulence phenotyp...

BACKGROUND Septoria tritici blotch (STB), caused by the fungus Zymoseptoria tritici, is a foliar disease affecting wheat crops against which conventional control methods are not totally effective. During inter‐epidemic periods the fungus survives in wheat residues left on the ground. In this study, we tested the potential of the collembolan Heterom...

In the context of global warming, it is crucial to focus on the effects of temperature on the emergence of new lineages of endemic pathogen species, such as Puccinia striiformis f. sp. tritici (Pst) the causal agent of yellow rust on wheat. We characterized the thermal aptitude of representative isolates from the most recent common European Pst rac...

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...

Deploying disease-resistant cultivars is one of the most effective control strategies to manage crop diseases such as wheat leaf rust, caused by Puccinia triticina. After harvest, this biotrophic fungal pathogen can survive on wheat volunteers present at landscape scale and constitute a local source of primary inoculum for the next cropping season....

Measuring dispersal is important for understanding how pathogen populations change in time and space, since capacity for dispersal is a fundamental fitness component. We measured rain splash-driven dispersal of the major fungal wheat pathogen Zymoseptoria tritici (Zt) and estimated its dispersal kernel in field conditions for the first time. We ino...

Varietal mixtures have been shown to limit plant pathogen expansion in numerous cases. This effect is related to the overall increase of functional diversity within fields, but the mechanisms involved, which are diverse and some of which are specific to the biology of the pathogen, are not all well characterised. Recent results obtained in the rice...

Septoria tritici blotch is a worldwide wheat disease caused by the fungal pathogen Zymoseptoria. tritici, that damages leaves through multiple infection asexual cycles and survive through sexual reproduction in crop residues left on the ground during the interepidemic period. Springtails (Collembola) are cosmopolitan soil arthropods and mycophagous...

Wheat cultivar mixtures can provide control against numerous diseases such as Septoria tritici blotch (STB) caused by Zymoseptoria tritici. One important criterion for mixture design is the contrast in resistance levels between the mixed cultivars, but these resistance levels can vary with local conditions (eg. composition of pathogen populations,...

The 2020 International Year of Plant Health was opportune for communication on plant diseases. During this year we illustrated the diversity and beauty of fungal plant pathogens found during "phytopathological strolls", in which we observed and determined the origin of symptoms on diseased plants found in our garden, in the local streets of a city...

In the context of global warming, it is crucial to focus on the effects of temperature on the emergence of new lineages of endemic pathogen species, such as Puccinia striiformis f. sp. tritici (Pst) the causal agent of yellow rust on wheat. We characterized the thermal aptitude of representative isolates from the most recent common European Pst rac...

Cet ouvrage collectif, rédigé par plusieurs auteurs membres de la Société Française de Phytopathologie, donne aux étudiants une vue globale des spécificités de la biologie et de l’écologie des agents phytopathogènes et de leurs interactions avec les plantes. Cet ouvrage collectif est le fruit d’une collaboration étroite entre les enseignants et les...

Le présent document constitue le rapport scientifique de l’Expertise scientifique collective (ESCo) sollicitée conjointement par les ministères de l’agriculture, de l’environnement et de la recherche. L’ESCo a été conduite par la Direction de l’Expertise scientifique collective, de la prospective et des études (DEPE) d’INRAE avec le soutien financi...

Plant resistances impose strong selective pressure on plant pathogen populations through the deployment of major resistance genes, which leads to the emergence of new virulences. The pathogen adaptation also involves other life-history or parasitic fitness traits, especially aggressiveness components. A previous study on Puccinia triticina, the cau...

Septoria leaf blotch is a foliar wheat disease controlled by a combination of plant genetic resistances and fungicides use. R-gene-based qualitative resistance durability is limited due to gene-for-gene interactions with fungal avirulence (Avr) genes. Quantitative resistance is considered more durable but the mechanisms involved are not well docume...

Plant pathogens are constantly evolving and adapting to their environment, including their host. Vir-ulence alleles emerge, and then increase, and sometimes decrease in frequency within pathogen populations in response to the fluctuating selection pressures imposed by the deployment of resistance genes. In some cases, these strong selection pressur...

Cet article fait office de compte rendu de la sortie mycologie et botanique organisée le 15 avril 2023 pour l’Association des Naturalistes des Yvelines (ANY ; https://www.siteany78.org/). Cette sortie en grande partie consacrée à la découverte des rouilles ou urédinales – micromycètes responsables d’une catégorie de maladies cryptogamiques Ô combie...

Abstract Dispersal is a key ecological process, but it remains difficult to measure. By recording numbers of dispersed individuals at different distances from the source, one acquires a dispersal gradient. Dispersal gradients contain information on dispersal, but they are influenced by the spatial extent of the source. How can we separate the two c...

Soil invertebrates play a key role in agrosystems as providers of several ecosystem services. In particular, they regulate fungal communities in soils and could contribute to mitigate the impact of phytopathogenic fungi overwintering in crop residues. In this study, we investigated the food preferences of Heteromurus nitidus (Col-lembola) between p...

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 f...

Fungal genus Septoria causes diseases in a wide range of plants. Here, we report the first genome sequences of two strains of Septoria linicola, the causal agent of the pasmo disease of flax ( Linum usitatissimum). The genome of the first strain, SE15195, was fully assembled in 16 chromosomes, while 35 unitigs were obtained for a second strain, SE1...

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 according to the virulence (‘vi...

The increased emergence of cereal stem rust in southern and western Europe, caused by the pathogen Puccinia graminis, and the prevalence of alternate (sexual) host, Berberis species, have regained attention as the sexual host may serve as source of novel pathogen variability that may pose a threat to cereal supply. The main objective of the present...

Plant pathogens are constantly evolving and adapting to their environment, including their host. Virulence alleles emerge, and then increase, and sometimes decrease in frequency within pathogen populations in response to the fluctuating selection pressures imposed by the deployment of resistance genes. In some cases, these strong selection pressure...

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 f...

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 o...

Thermal ecology studies on the ecophysiological responses of organisms to temperature involve two paradigms: physiological rates are driven by body temperature and not directly by the environmental temperature, and they are largely influenced not only by its mean but also its variance. These paradigms together have been largely applied to macro inv...

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 evol...

La rouille noire du blé causée par le champignon Puccinia graminis f. sp. tritici s’est faite quelque peu oubliée en Europe depuis le milieu du siècle dernier. Toutefois, les signalements se sont multipliés au cours des dix dernières années, signe d’une possible réinstallation de la maladie. En 2021, la rouille noire a été observée sur l’ensemble d...

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 i...

Zymoseptoria tritici, the causal agent of Septoria tritici blotch, is found in all continents on both bread and durum wheat under various climatic conditions, at different seasons, in different substrates consisting of living or decomposing host tissues, and in various more or less cryptic fungal forms (pycnidiospores, mycelium, ascospores, chlamyd...

Reproducing splash-dispersed diseases epidemics under controlled conditions is technically challenging since current rain-generating equipment cannot be used in conventional controlled environment rooms. This compels us to test evolutionary scenarios one-at-a-time and only in semi-controlled or natural environments. Thus, the investigation of the e...

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 suscepti...

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 o...

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 virul...

Plant pathogen populations inhabit patchy environments with contrasting, variable thermal conditions. We investigated the diversity of thermal responses in popula- tions sampled over contrasting spatiotemporal scales, to improve our understanding of their dynamics of adaptation to local conditions. Samples of natural populations of the wheat pathog...

Capacity for dispersal is a fundamental fitness component of plant pathogens. Characterization of plant pathogen dispersal is important for understanding how pathogen populations change in time and space. We devised a systematic approach to measure and analyze rain splash-driven dispersal of plant pathogens in field conditions, using the major fung...

Foliar plant pathogens require liquid or vapour water for at least part of their development, but their response and their adap-tive tolerance to moisture conditions have been much less studied than other meteorological factors to date. We examined the impact of altering optimal moisture conditions conducive to infection on the wheat-Zymoseptoria t...

Cultivar mixtures slow polycyclic epidemics but may also affect the evolution of pathogen populations by diversifying the selection pressures exerted by their plant hosts at field scale. We compared the dynamics of natural populations of the fungal pathogen Zymoseptoria tritici in pure stands and in three binary mixtures of wheat cultivars (one sus...

Given the negative environmental effects of conventional agricultural techniques, the need for biodiversity-friendly agriculture systems that rely more on ecosystem services and less on chemical inputs is becoming increasingly urgent. In this paper, we focus on crop protection strategies that are alternatives to the use of pesticides. Diversificati...

I illustrate here the diversity and beauty of fungal plant pathogens through a naturalist approach, returning to the “basics” of phytopathology. I achieve this end through presenting one-year ‘phytopathological strolls’, in which I observed and determined the origin of symptoms on diseased plants found around hedgerows, in my garden, in the local s...

La rouille brune est l’une des principales maladies du blé (Triticum aestivum). Elle est causée par un champignon, Puccinia triticina, dont les populations possèdent un niveau de diversité relativement élevé. La structure des populations est fortement influencée par la variété. Après la récolte, le champignon peut survivre sur des repousses de blé,...

This study combined culture-dependent (strain isolation plus molecular identification) and culture-independent (metabarcoding) approaches to characterize the diversity of microbiota on wheat and oilseed rape residues. The goal was to develop a methodology to culture microorganisms with the aim of being able to establish synthetic crop residue micro...

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...

Dispersal is a key ecological process, but remains difficult to measure. By recording numbers of dispersed individuals at different distances from the source one can acquire a dispersal gradient. Although dispersal gradients contain information on dispersal, they are influenced by the spatial extent of the source. How can we separate the two contri...

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-s...

AVIS de l’Agence nationale de sécurité sanitaire de l’alimentation, de l’environnement et du travail relatif à « la stratégie de lutte vis-à-vis de Xylella fastidiosa - phase 2 ». L’Anses a été saisie le 28 septembre 2020 par la Direction générale de l’alimentation pour la réalisation de l’expertise suivante : demande d'appui scientifique et techni...

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...

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...

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 characterize the impact of a resistance gene against L. maculans infection on residue microbial communities and to identify microorganisms interacting with th...

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...

AVIS de l’Agence nationale de sécurité sanitaire de l’alimentation, de l’environnement et du travail relatif à « la stratégie de lutte vis-à-vis de Xylella fastidiosa ». L’Anses a été saisie le 26 novembre 2019 par la Direction générale de l’alimentation pour la réalisation de l’expertise suivante : demande d’avis relatif à la stratégie de lutte vi...

Background: Wheat residues are a crucial determinant of the epidemiology of Septoria tritici blotch, as they support the sexual reproduction of the causal agent Zymoseptoria tritici. We aimed to characterize the effect of infection with this fungal pathogen on the microbial communities present on wheat residues and to identify microorganisms inter...

Background Wheat residues are a crucial determinant of the epidemiology of Septoria tritici blotch, as they support the sexual reproduction of the causal agent Zymoseptoria tritici . We aimed to characterize the effect of infection with this fungal pathogen on the microbial communities present on wheat residues, and to identify microorganisms inter...

The negative contribution of crop residues as a source of inoculum for plant diseases is well established. However, microbial ecologists have long reported positive effects of residues on the stability of agrosystems and conservation tillage practices have become increasingly widespread. Most studies have suggested that large microbial communities...

Deciphering the responses of microbial populations to spatiotemporal changes in their thermal environment is instrumental in improving our understanding of their eco-evolutionary dynamics. Recent studies have shown that current phenotyping protocols do not adequately address all dimensions of phenotype expression. Therefore, these methods can give...

Crop production is crucial for all countries and a deliberate use of plant pathogens (agroterrorism sensu lato) represents a threat for global food security and bioeconomy. Obtaining certain microorganisms is an critical component of the risk. Lists of regulated microorganisms were elaborated to limit this component, for instance by the Australia G...

Wheat foliar pathogens inhabit crop canopies that are subjected to substantial spatio-temporal variations in temperature. Given the pronounced diversity in thermal individual responses within a local Zymoseptoria tritici population, these environmental heterogeneities may lead to phenotypic selection in the field. Signatures of response to thermal...

Septoria leaf blotch (STB) caused by Zymoseptoria tritici is one of the most damaging fungal pathogen on durum wheat. The genetic diversity of Z. tritici populations has already been the subject of numerous studies but no study has compared the genetic diversity of these fungal populations present on genetically diverse hosts such as landraces and...

Zymoseptoria tritici is a hemibiotrophic fungus responsible for the septoria leaf blotch (STB) disease on wheats and triticale. Strains of the fungus are not only host species specific, but also show specificity to varieties. This specificity is often explained by a gene-for-gene interaction between resistance genes in hosts and pathogenicity genes...

Temperature and moisture are critical micrometeorological factors affecting each epidemiological stage of foliar diseases. Several studies reported thermal adaptation of plant pathogens, including Zymoseptoria tritici, but no similar investigation has been carried out on the response and adaptation to moisture conditions. To detect if there is evid...