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Impact of snowmelt on the population structure of the plant pathogen Pseudomonas syringae in an alpine
hydrological system
Caroline Monteil, Catherine Glaux, Caroline Guilbaud, Adrien Pasquier, Francois Lafolie, Cindy E. Morris
To cite this version:
Caroline Monteil, Catherine Glaux, Caroline Guilbaud, Adrien Pasquier, Francois Lafolie, et al..
Impact of snowmelt on the population structure of the plant pathogen Pseudomonas syringae in an alpine hydrological system. 13. International symposium on microbial ecology, Aug 2010, Seattle, United States. �hal-02751258�
Version postprint
Comment citer ce document :
Monteil, C., Glaux, C., Guilbaud, C., Pasquier, A., Lafolie, F., Morris, C. E. (2010). Impact of snowmelt on the population structure of the plant pathogen Pseudomonas syringae in an alpine
hydrological system. In: ISME13 (p. 1 p.). Presented at 13. International symposium on microbial ecology, Seattle, USA (2010-08-22 - 2010-08-27).
13th international symposium on microbial ecology. August 22-27 2010, Seattle, USA
IMPACT OF SNOWMELT ON THE POPULATION STRUCTURE OF THE PLANT PATHOGEN PSEUDOMONAS SYRINGAE IN AN ALPINE HYDROLOGICAL SYSTEM
Caroline L. MONTEIL1, Catherine GLAUX1, Caroline GUILBAUD1, Adrien PASQUIER1, François LAFOLIE 2 et Cindy E. MORRIS1
1-INRA, Unité de Pathologie Végétale, Domaine St Maurice, BP. 94, 84140 Montfavet cedex, France.
2-INRA, Unité Climat-Sol-Environnement, Domaine Saint-Paul, Site Agroparc, 84914 Avignon, France.
Recent reports reveal that the life cycle of the plant pathogen Pseudomonas syringae is associated with the water cycle; it inhabits snow and alpine rivers in particular. In this light, our objective is to model the transfer of populations of P. syringae during snowmelt towards the first overland flows in the Southern French Alps. We estimated abundance and the phenotypic diversity (ice nucleation activity, production of toxins, and pathogenicity) of P. syringae in the snow cover at three sites in the Southern French Alps and the associated streams. P. syringae was detected in the water and the snow cover at all sites during the sampling period (March to June). Abundance of P. syringae and population structure was stratified along the depth of the snow cover. In the 10-cm layer of snow in contact with the ground, population sizes were significantly greater and the dominant phenotypes changed during the season relative to that in snow closer to the surface where populations were less dense and more stable.
Surprisingly the population structure in adjacent stream water was different from that in snow. Our field observations coupled to microcosm studies have led us to propose a preliminary conceptual model of the processes involved that modify population structure from snowmelt to stream flow. In winter, P. syringae arrives in the basin with the first snow falls. Populations in this initial snow layer consist of strains arriving with the snow and those already present on the leaf litter. Populations survive, multiply and die during the winter as a function of organic matter availability, humidity, the low conductivities and the temperature (always ca. 0°C in the snow cover). Then, the meltwater infiltrates gradually into the ground;
the geology of the site determines its residence time and its chemistry. The capacity of P. syringae subpopulations to survive transport depends on their fitness in face of the conditions determined by water chemistry and residence time.
