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Investigation of Sclerotinia sclerotiorum strains variability in Brazil
1Departamento de Biologia, Universidade Federal de Lavras, Lavras, MG, Brasil.
Abstract:
White mold is a common bean disease caused by the fungus Sclerotinia sclerotiorum, resulting in economic losses in Brazil and worldwide. Lack of knowledge about the population structure of the pathogen makes it difficult to control the disease. The aim of this study was to characterize strains of S. sclerotiorum obtained from ex-perimental and commercial common bean fields in Brazil. We analyzed 50 strains of S. sclerotiorum collected at several locations in the state of Minas Gerais. The strains were characterized according to their ability and time for developing apothecia. Morphological and physiological analyses such as the mycelial growth index, colony color, the time re-quired to form the first sclerotia on media, the number of sclerotia per plate, average sclerotium size, and sclerotium shape were performed. We determined the mycelial compatibility, conducted molecular analy-sis of microsatellites, and evaluated the aggressiveness of 28 strains. Most strains had the ability to form apothecia. A small group of strains showed mycelial compatibility, and the strains showed different aggres-siveness levels. Overall, the population studied here demonstrated wide variability based on the morphological, physiological, and molecular traits analyzed. The average size and shape of sclerotia presented a cor-relation of 0.617, whereas the times required to form sclerotia and the number of sclerotia per plate showed a correlation of -0.455. The char-acterization of the pathogen population described herein will provide an important tool for promoting the development of bean cultivars re-sistant to white mold.
Insights
White mold, a significant bean disease, shows high variability in Brazilian pathogen populations. Understanding this diversity is key to developing resistant bean cultivars and managing crop losses.
Area of Science:
- Plant Pathology
- Agricultural Science
- Mycology
Background:
- White mold, caused by *Sclerotinia sclerotiorum*, poses a major threat to common bean production globally and in Brazil.
- Effective disease management strategies are hindered by insufficient knowledge of the pathogen's population structure.
- Characterizing *S. sclerotiorum* strains is crucial for developing targeted control measures.
Purpose of the Study:
- To characterize the population structure of *Sclerotinia sclerotiorum* strains from Brazilian common bean fields.
- To analyze morphological, physiological, and molecular variability among these pathogen strains.
Main Methods:
- Analysis of 50 *S. sclerotiorum* strains from Minas Gerais, Brazil.
- Evaluation of apothecial development, mycelial growth, colony characteristics, and sclerotia formation (time, number, size, shape).
- Determination of mycelial compatibility, microsatellite molecular analysis, and aggressiveness assessment of 28 strains.
Main Results:
- Most strains exhibited the ability to form apothecia, indicating reproductive potential.
- Significant variability was observed across morphological, physiological, and molecular traits.
- A subset of strains displayed mycelial compatibility, and varying levels of aggressiveness were noted.
Conclusions:
- The *S. sclerotiorum* population in the studied region demonstrates broad genetic and phenotypic diversity.
- This detailed characterization provides a foundation for developing common bean cultivars with enhanced resistance to white mold.
- Understanding pathogen variability is essential for sustainable agricultural practices and disease control.
