Characterization of Sclerotinia sclerotiorum airborne inoculum, the widespread agent of white mould disease
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A means to rationalize the use of fungicides for crop protection and to make agriculture friendlier to environment and human health is to develop disease-risk forecasting systems based on the assessment of airborne inoculum abundance. Sclerotinia sclerotiorum, the pandemic agent of white mould disease, is disseminated via the atmosphere in the form of ascospores. These airborne spores are the primary sources of inoculum initiating the majority of epidemics. However, for witloof chicory (Cichorium intybus var. foliosum L.), there is no data about airborne inoculum of S. sclerotiorum, which makes it difficult to develop a forecasting model. In the present study, we characterized the temporal evolution of the abundance and of the genetic characteristics of S. sclerotiorum inoculum on a witloof chicory field located in Northern France over a 3-year period. To our knowledge, this study provides the first quantification of viable airborne populations of this fungus in witloof chicory crops. Moreover, it provides the first genetic characterization of S. sclerotiorum airborne inoculum. The results show that viable ascospores were present through 80% of the sampling dates. A significant correlation between abundance of airborne ascospores and local relative humidity suggests a local origin of inoculum. However, the existence of a slight genetic differentiation between isolates carried by air masses coming from the West and from the North-West is compatible with the hypothesis of a distant origin of S. sclerotiorum inoculum. We discuss the additional studies that are envisioned to clarify the origin of S. sclerotiorum airborne inoculum in witloof chicory fields.
KeywordsAir mass trajectory Ascospores Quantification Microsatellite markers Witloof chicory
This study was supported in part by a CASDAR grant of the French Ministry of Agriculture (SCLEROLEG Project) and by the Groupement d’Intérêt Scientifique pour la Production Intégrée des Cultures légumières (GIS PIClég).
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Conflict of interest
The authors declare that they have no conflict of interest.
- Clarkson, J. P., Warmington, R., Walley, P. G., Denton-Giles, M., Barbetti, M. J., Brodal, G., et al. (2017). Population structure of Sclerotinia subarctica and Sclerotinia sclerotiorum in England. Scotland and Norway: Frontiers in Microbiology. https://doi.org/10.3389/fmicb.2017.00490.Google Scholar
- Draxler, R. R., & Rolph, G. D. (2011). HYSPLIT (HYbrid Single-Particle Lagrangian Integrated Trajectory) Model access via NOAA ARL READY. NOAA Air Resources Laboratory, Silver Spring, MD. http://ready.arl.noaa.gov/HYSPLIT.php. Accessed 10 Jan 2018.
- Excoffier, L., Laval, G., & Schneider, S. (2005). Arlequin ver. 3.0: An integrated software package for population genetics data analysis. Evolutionary Bioinformatics Online, 1, 47–50.Google Scholar
- Falush, D., Stephens, M., & Pritchard, J. K. (2003). Inference of population structure using multilocus genotype data: Linked loci and correlated allele frequencies. Genetics, 164(4), 1567–1587.Google Scholar
- Leroy, T., Caffier, V., Celton, J. M., Anger, N., Durel, C. E., Lemaire, C., et al. (2016). When virulence originates from nonagricultural hosts: evolutionary and epidemiological consequences of introgressions following secondary contacts in Venturia inaequalis. New Phytologist, 210(4), 1443–1452.CrossRefGoogle Scholar
- Lewartowska, E., Jedryczka, M., & Frencel, I. (1996). Pathogenicity of Sclerotinia sclerotiorum (Lib.) de Bary isolates from different localities of rapeseed in Poland. In: Proceedings scientific symposium on plant diseases and the environment, Poznan, Poland. 27–28 June 1996.Google Scholar
- Meier, F. C., Stevenson, J. A., & Charles, V. K. (1933). Spores in the upper air. Phytopathology, 23, 23.Google Scholar
- Petrofeza, S., & Nasser, L. C. B. (2012). Case study: Sclerotinia sclerotiorum—genetic diversity and disease control. In M. Caliskan (Ed.), The molecular basis of plant genetic diversity. Delhi: InTech.Google Scholar
- Rolph, G. D. (2011) Real-time environmental applications and display system (READY). NOAA Air Resources Laboratory, Silver Spring, MD. http://ready.arl.noaa.gov. Accessed 10 Jan 2018.