Adaptive and epidemiological processes in wheat-fungal pathogen interactions

ADEP

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Our team investigates the adaptive and epidemiological processes in wheat-fungal pathogen interactions. We characterize the determinants and the consequences of these processes at different scales. Our applied goal to strengthen wheat immunity and control inoculum sources, thereby enhancing the efficiency and the durability of disease management strategies, in the context of climate change and agroecological transition. Our case study is Zymoseptoria tritici (Septoria leaf blotch) and, most recently, Puccinia graminis f. sp. tritici (stem rust) as re-emerging pathogen.

The interactions between pathogen populations and host plant populations are determined by the biology and life style of the pathogen, by the selective pressure exerted by the host (species and variety) and abiotic factors (climatic conditions). The processes involved in adaptive dynamics are often specific to temporal scales (intra- and inter-epidemic periods) and spatial scales (gene, plant, field). All these considerations pave the research strategy of our team, which is based on four interdependent objectives:

1. Characterize the processes responsible for adaptive dynamics in populations of Z. tritici

2. Understand the genetic and genomic determinism of Z. tritici adaptation and decipher molecular mechanisms of infection

3. Explore the determinism and epidemiological consequences of sexual reproduction in Z. tritici

4. Assess the impact of interactions between cultivated and wild plants on the benefit-risk balance of crop diversification in cereal systems

Our team is composed of three scientists and two technicians, one of whom shares her molecular biology activities with two other teams. We benefit from the support of contract collaborators (engineers, postdoctoral researchers) and scientists in training (PhD students and interns at the master's level M1 or M2). We are attached to the LabEx SPS / OI C-BASC and affiliated to the SEVE and ABIES doctoral schools.

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In this folder

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Congratulations to Cécilia Fontyn, who was honored with the "Young Plant Pathologist" award for the latest article from her PhD, published in the "Fresh Ideas in Plant Health" section of the Journal of Plant Pathology.

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Ulysse Guillotteau and Alicia Culot joined the ADEP team in October and November 2024 for a PhD.

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The quantitative component of pathogenicity in Zymoseptoria tritici and its adaptation to its host has been deciphered through whole-genome sequencing of the fungus followed by a pangenome-wide association study. This study, led at BIOGER by Thierry Marcel, has recently been published in the journal Nature Communications.

A study conducted by Thomas Bourgeois, a PhD student at MNHN*, in collaboration with BIOGER, has shown that the springtail Heteromurus nitidus "grazes" the fruiting bodies of Zymoseptoria tritici (septoria) on infected wheat tissues, thereby reducing the amount of available inoculum.

Using wheat leaf rust as a case study, an experimental study conducted at BIOGER showed that higher aggressiveness (a quantitative component of pathogenicity) can compensate for a lack of virulence, meaning the inability to infect wheat varieties carrying a widely deployed resistance gene. This finding suggests that even if a pathogen lacks the specific ability to overcome certain resistance mechanisms, its overall aggressiveness — such as its ability to infect more rapidly or spread extensively — can still lead to significant disease development.

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A study conducted at BIOGER showed that it is possible to estimate the frequency of virulent strains in a pathogen population through "bulk" phenotyping on micro-wheat plots arranged in a checkerboard pattern.

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Several teams from BIOGER were represented at ISCLB2024 in Zurich, highlighting the diversity of work being conducted on wheat septoria within our unit. This participation has strengthened the international visibility of our research, which is now well-recognized.

feuille de blé infectée par Puccinia striiformis f. sp. tritici

Answers to this question have recently been provided by Kevin Meyer and epidemiologist colleagues at BIOGER as part of the European H2020 RustWatch project.