Plant Pathology Research Unit of INRA - Avignon, France

The Plant pathology research unit at INRA-Avignon is comprised of 42 permanent staff including 12 scientists and is part of the INRA-Avignon Center that houses over 500 permanent staff in a dozen research units covering all aspects of plant production. The unit conducts research on diseases of Mediterranean market garden crops and viral diseases of flower crops. This includes: identification of plant pathogens and description of their genetic and phenotypic diversity, the development of rapid, simple and reliable diagnosis methods, studies of the conditions that enhance the spread of epidemics, evaluation of the impact of biotic and abiotic factors on the effectiveness and durability of control methods and especially plant resistance to pathogens and analysis of the variability potential of phytopathogens. The work as a whole is aimed at the development of effective, rational control methods that respect the environment and make it possible to produce high-quality fruits and vegetables.

One branch of INRA’s research concerns the dissemination of pathogens – from microscopic to global scales. The specific number of viral particles transmitted by an insect vector has been elucidated, the pioneer genotypes leading to gray mold epidemics have been identified among the diverse air spora of Botrytis cinerea in greenhouses, the regional spread of the emerging Watermelon Mosaic Virus variants in France, and the world-wide dissemination of plant pathogenic and ice nucleation active bacteria with the water cycle has been demonstrated. This work emanates from INRA’s team competence in evaluating the spectrum of pathogen variability – from genetic, to serological, to variation in pathogenicity and other phenotypes – and in exploiting this variability to make experimental tools.
In the areas of disease etiology and traits related to pathogenicity, the pathogens responsible for a new bacterial disease in France and multiple viral diseases throughout the Mediterranean basin and the molecular factors linked to the transmission of these agents, to symptom expression and to the emergence of highly aggressive and as well as non pathogenic variants have been identified.

INRA has also contributed to developing disease control methods and evaluating the durability of these methods. For over the past 20 years INRA contributed to the development of disease resistant lines of vegetable crops in collaboration with the plant breeding research unit at Avignon. Studies of pathogen ecology and disease epidemiology have led to the development of two biological control agents for which markets are being opened on the national and international levels. Work in progress is directed towards evaluating the durability of disease resistance in crops as well as that of the efficacy of biological protection agents.

Facilities: Microscopy platform: light and electronic (TEM and SEM) microscopy, cell imaging and data treatment; Serology laboratory; Molecular biology platform: 2000 m2 of greenhouses, 100 m2 of containment greenhouses, 10 plant growth chambers, fully–equipped laboratories for isolation, preservation and characterization of bacteria, fungi and viruses etc.

Principal Staff involved:

Drs Cecile Desbiez, Mireille Jacquemond, Herve Lecoq, and Benoit Moury are research scientists, experts in diagnosis, epidemiology and control of virus diseases. The virology group developed molecular and serological tools for detecting most of the viruses found in vegetable and ornamental crops. The group is also recognized for its expertise in the study of the molecular determinants for pathogenicity, in close relation with the study of resistance durability. HL is the actual president of the international ISHS working group.