Differential susceptibility to the mycoparasite Paraphaeosphaeria minitans among Sclerotinia sclerotiorum isolates
The mycoparasitic fungus Paraphaeosphaeria minitans (formerly Coniothyrium minitans), is increasingly used by farmers to reduce soilborne inoculum of Sclerotinia sclerotiorum. In France, its field efficacy tends to be higher in the North than in the South, leading to the hypothesis of possible regional differences in the susceptibility of the pathogen to the biocontrol agent. A standardized assay was developed and four quantitative criteria were used to assess the susceptibility to P. minitans of 75 S. sclerotiorum isolates collected from different regions of France. There was no significant difference between the group of isolates from the North and that from the South, but wide differences were observed among isolates, with consistent responses for all quantitative criteria. This study suggests that biocontrol efficacy might vary locally depending on the frequency of less susceptible isolates and it brings to attention the possibility that selection pressure could lead to a gradual increase in the frequency of less susceptible isolates, as this biocontrol method becomes widely adopted by farmers. To our knowledge, this is the first report of the variable susceptibility of S. sclerotiorum to a commercialized strain of P. minitans and the first detailed characterization of a large group of isolates from France for traits related to fitness, such as mycelial growth and production of sclerotia.
KeywordsBiological control Coniothyrium Hyperparasite Durability Sclerotia White mold
This work was supported in part by funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 633184 (“EUCLID” project) and by a CASDAR grant from the French Ministry of Agriculture together with the Scientific Interest Group “GIS PICLég” (“ScleroLeg” project). The authors thank all the field experimenters of the French technical institutes (CTIFL, ACPEL, APEF, CEFEL, Invenio, SILEBAN, Terres Inovia UNILET) who collaborated in the project and who collected the isolates used in the present study.
- De Vrije T, Antoine N, Buitelaar R, Bruckner S, Dissevelt M, Durand A, Gerlagh M, Jones E, Lüth P, Oostra J (2001) The fungal biocontrol agent Coniothyrium minitans: production by solid-state fermentation, application and marketing. Applied Microbiology and Biotechnology 56:58–68CrossRefGoogle Scholar
- Elsheshtawi M, Elkhaky MT, Sayed SR, Bahkali AH, Mohammed AA, Gambhir D, Mansour AS, Elgorban AM (2017) Integrated control of white rot disease on beans caused by Sclerotinia sclerotiorum using Contans® and reduced fungicides application. Saudi Journal of Biological Sciences 24:405–409CrossRefGoogle Scholar
- Huang HC, Erickson RS (2000) Soil treatment with fungal agents for control of apothecia of Sclerotinia sclerotiorum in bean and pea crops. Plant Pathology Bulletin 9:53–58Google Scholar
- Leyronas C, Duffaud M, Nicot PC (2012) Compared efficiency of the isolation methods for Botrytis cinerea. Mycology: An International Journal on Fungal Biology 3:221–225Google Scholar
- Nicot P, Bardin M, Alabouvette C, Köhl J (2011) Potential of biological control based on published research. 1. Protection against plant pathogens of selected crops. In: Nicot P (ed) Classical and augmentative biological control against diseases and pests: critical status analysis and review of factors influencing their success. IOBC/WPRS, Zürich, pp 1–11Google Scholar
- Nicot PC, Avril F, Duffaud M, Leyronas C, Troulet C, Villeneuve F, Bardin M (2016) Are there regional differences in the susceptibility of Sclerotinia sclerotiorum strains to Coniothyrium minitans? IOBC WPRS Bulletin 117:83–87Google Scholar
- Shrestha U, Augé RM, Butler DM (2016) A meta-analysis of the impact of anaerobic soil disinfestation on pest suppression and yield of horticultural crops. Frontiers in Plant Science 7:1254Google Scholar
- von Tiedemann A, Hedke K, Mögling R (2001) Abbauverhalten von Sklerotien der Weißstängeligkeit bei Einsatz von Contans. Raps 1:1–3Google Scholar
- Willbur JF, Fall ML, Bloomingdale C, Byrne AM, Chapman SA, Isard SA, Magarey RD, McCaghey MM, Mueller BD, Russo JM, Schlegel J, Chilvers MI, Mueller DS, Kabbage M, Smith DL (2018) Weather-based models for assessing the risk of Sclerotinia sclerotiorum apothecial presence in soybean (Glycine max) fields. Plant Disease 102:73–84CrossRefGoogle Scholar