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INRAE

24, chemin de Borde Rouge -Auzeville - CS52627 31326 Castanet Tolosan cedex - France

Last update: May 2021

Menu Logo Principal Plant pathology unit - INRA AVIGNON

Pathologie vegetale

Zone de texte éditable et éditée et rééditée

LEYRONAS Christel

Engineer, Mistral team

My research concerns how the aerial inoculum of broad host-range plant pathogens (fungi in particular) affects the risk of epidemics and the management of plant health.

CONTACT/PROFIL

 

 

LEYRONAS Christel

Unité de Recherches de Pathologie Végétale
INRAE PACA

cm

Domaine St Maurice BP 94
67, allée des chênes
CS 60094
F84143 Montfavet cedex
France

Tel : 33 (0) 4.32.72.28.67

christel.leyronas(a)inrae.fr

HAL INRAE

My publications in the open archive HAL INRAE

ORCID

        https://orcid.org/0000-0002-2693-1140

ACTIVITES DE RECHERCHE

My research projects cover fundamental questions about disease epidemics all while being rooted in concerns with direct importance for production in the field. I collaborate with horticultural sectors that encounter fungal diseases. With the overall objective of optimizing the reasoned protection of crops, my work aims to 1) -identify and characterize pathogens, 2) - identify reservoirs of inoculum and 3) - evaluate the aerial dissemination at local to global scales. To accomplish this, I design experimental set-ups and develop sampling strategies and methodologies for the quantification of airborne inoculum and its phenotypic and genetic characterization.

I work mostly on diseases caused by fungi with broad host ranges including Botrytis cinerea (grey mold), Sclerotinia sclerotiorum (white mold), and Fusarium proliferatum. Whereas B. cinerea and S. sclerotiorum have caused recurrent epidemics for decades on various horticultural crops in France – importantly on tomato and lettuce, respectively – F. proliferatum has only recently emerged as a pathogen on garlic (Leyronas, C., et al. (2018). First report of Fusarium proliferatum causing garlic clove rot in France. Plant Disease, 102 (12), 2658. DOI: 10.1094/PDIS-06-18-0962-PDN)

Identify and characterize pathogens

Clarifying the etiology of a disease is an essential first step toward an effective and lasting control method against this disease. This involves identifying the species responsible for the symptoms as well as a detailed characterization of the individuals within the species.

Strains of Sclerotinia sclerotiorum collected from a range of plant hosts (carrot, rapeseed, witloof chicory, beans, lettuce, and cantaloupe) grouped according to their haplotype

Sclerotinia sclerotiorum
Strains of Sclerotinia sclerotiorum collected from a range of plant hosts (carrot, rapeseed, witloof chicory, beans, lettuce, and cantaloupe) grouped according to their haplotype

Research on the etiology of garlic brown rot, a newly emerging disease in France

Research on the etiology of garlic brown rot, a newly emerging disease in France
Research on the etiology of garlic brown rot, a newly emerging disease in France

Identify reservoirs of inoculum

Phylogenetic tree indicating the relationships and genetic distance among strains of Botrytis cinerea collected from within and outside of agricultural habitats

Identifying the sources of inoculum is essential for understanding the epidemiology of disease and ultimately predicting epidemic risks. Locating them is all the more difficult when a pathogen has a broad host range, a saprophytic phase on various substrates in and outside of cropped fields and can survive during aerial transport - as is the case for the organisms that I study. It is becoming increasingly evident that we must take into account the diversity of what is outside the agricultural plots (that is to say expand beyond a solely agro-centered vision) to fully understand epidemiological phenomena.

Phylogenetic tree indicating the relationships and genetic distance among strains of Botrytis cinerea collected from within and outside of agricultural habitats. (click on the image to enlarge)

Evaluate aerial spread from local to global scales

Unlike the spread of pathogens with human activities, aerial spread is difficult to control because air masses know few borders. Although we cannot stop the movement of pathogens in the atmosphere, we can try to elucidate their pathways in order to anticipate them and predict epidemic risks in different areas. To predict the arrival of spores in areas where susceptible crops are grown, it is necessary to identify the sources of spores, local and distant, and to model the trajectories of air masses. For polyphagous fungi with important saprophytic phases such as B. cinerea and S. sclerotiorum, predicting the arrival of spores is particularly difficult because there are many possible sources of inoculum and they cannot be all easily identified.

Identifying the path of microorganisms in the air is accomplished by indirect means: observation of the development of a disease in an area distant from the source area, comparison of the genetic profiles of individuals at the source and at the sink, capture of particles suspended in the air using specialized equipment, and modeling air mass trajectories.

Characteristic air masses that typically arrive in the region of Avignon

Characteristic air masses that typically arrive in the region of Avignon

Relationship between the haplotype profiles of strains of B. cinerea and the origin of air masses that potentially transported them to the collection site (Avignon)

Relationship between the haplotype profiles of strains of B. cinerea and the origin of air masses that potentially transported them to the collection site (Avignon)

Relationship between aerial connectivity (colored arrows) that links different regions of France (North, Northwest, Southwest, Central-west) and haplotype profiles (colored rectangles) for strains of S. sclerotiorum collected in these same regions

Relationship between aerial connectivity (colored arrows) that links different regions of France (North, Northwest, Southwest, Central-west) and haplotype profiles (colored rectangles) for strains of S. sclerotiorum collected in these same regions

 

MANAGEMENT

I am strongly interested in the managerial aspects of research and in particular the management of human resources where staff work in teams. Since 2016 I have been deputy director of the Plant Pathology unit (42 permanent staff) in charge of human resources. Managing human resources is a real balancing act (between kindness and high standards, between the interests of the collective and that of the individual, ...). It is also a continuous and iterative process of questioning and adjustment (of oneself and of the group) for an optimal functioning, so that everyone finds their place, a meaning and satisfaction in their activities, while keeping the common goal in sight.

In addition to the direct experience I have acquired, I have followed training in personnel management, communication, conflict management, personal development (transactional analysis, resilience ...) in order to acquire and implement tools encouraging the coherence and cohesion of groups and teams. Within my unit, I have created groups promoting the integration of newcomers (AIMIE workshops: discovery of the unit's experimental facilities through a visit and practical activities), providing support to colleagues who are candidates for internal evaluations and promotion (career support group), and optimizing the quality of life at work (AQuaViT: organization of occasional internal cohesion events). My motto is the African proverb that says "alone we go faster, but together we go further"

Human resources
"alone we go faster, but together we go further"