A method for inducing apothecia from sclerotia of Sclerotinia sclerotiorum

A Coniothyrium minitans strain (T3) co-transformed with the genes for b-glucuronidase (uidA) and hygromycin phosphotransferase (hph), the latter providing resistance to the antibiotic hygromycin B, was used to investigate the survival and infection of sclerotia of Sclerotinia sclerotiorum by C. minitans over time in four different soils. Infection of sclerotia was rapid in all cases, with the behaviour of transformant T3 and wild type parent A69 being similar. Differences were seen between the soils in the rate of infection of sclerotia by C. minitans and in their indigenous fungal populations. Amendment of agar with hygromycin B enabled the quantification of C. minitans in soil by dilution plating where there was a high background of other microorganisms. In Lincoln soil from New Zealand, which had a natural but low population of C. minitans, the hygromycin B resistance marker allowed the umambiguous discrimination of the applied transformed isolate from the indigenous hygromycin B sensitive one. In this soil, although the indigenous C. minitans population was detected from sclerotia, none were recovered on the dilution plates, indicating the increased sensitivity of C. minitans detection from soil using sclerotial baiting. C. minitans was a very efficient parasite, being able to infect a large proportion of sclerotia within a relatively short time from an initially low soil population. The addition of hygromycin B to agar also allowed the detection of C. minitans from decaying sclerotia by inhibiting secondary fungal colonisers. This is the first report to show that fungi colonising sclerotia already infected by C. minitans mask the detection of C. minitans from sclerotia rather than displacing the original parasite.

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“…Sclerotia of Sclerotinia sclerotiorum isolate G18 were produced using the method of Mylchreest & Wheeler (1987). 25 g of wheat grain (cv.…”

Section: Sclerotial Productionmentioning

confidence: 99%

Use of Coniothyrium minitans transformed with the hygromycin B resistance gene to study survival and infection of Sclerotinia sclerotiorum sclerotia in soil

Jones¹,

Stewart

Whipps³

2003

Mycological Research

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“…Two isolates of S. sclerotiorum, originally from glasshouse lettuce (SB; Whipps & Budge, 1990) and winter oilseed rape (JN1; Mylchreest & Wheeler, 1987), were used. C. minitans (IMI 134523) was isolated from sclerotia of S. sclerotiorum (Turner & Tribe, 1976).…”

Section: Source and Maintenance Of Fungimentioning

confidence: 99%

“…Armada, following inoculation and incubation at 20ЊC for 3 weeks (Mylchreest & Wheeler, 1987). Washed, air-dried sclerotia (c. 2-4 mm diameter) were selected for film-coating.…”

Section: Inoculum Production Of Fungimentioning

confidence: 99%

Biological control of Sclerotinia sclerotiorum by film‐coating Coniothyrium minitans on to sunflower seed and sclerotia

McQuilken¹,

Budge²,

Whipps³

1997

Plant Pathology

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Conidia of the biological control agent, Coniothyrium minitans, were applied to uninfected and S. sclerotiorum-infected sunflower seeds and to sclerotia of two isolates of S. sclerotiorum by polymer filmcoating, using a fluidised-bed seed treater. Rates of 5 × 10 6 and 7-14 × 10 6 conidia per g of seed and sclerotia were obtained, respectively. The activity of C. minitans was compared to treatments with the fungicides thiram þ fenpropimorph and iprodione. In agar plate tests, C. minitans increased seed germination and decreased recovery of S. sclerotiorum from S. sclerotiorum-infected seeds. However, in seedling tests carried out in a potting compost-soil mix with S. sclerotiorum-infected seeds, C. minitans failed to increase survival of seedlings. A high and low rate of thiram þ fenpropimorph and a high rate of iprodione film-coated onto S. sclerotiorum-infected seeds gave consistently better results than C. minitans in these tests. The film-coating process slightly decreased the germination of C. minitans conidia recovered from sunflower seeds and sclerotia of S. sclerotiorum, but after storage for 1 year at 10ЊC C. minitans grew from more than 97% of seed and sclerotia, and the number of colony forming-units per g seed or sclerotia had declined by less than 1 log 10 unit. In agar plate tests, all fungicide treatments were more effective than C. minitans in delaying myceligenic germination of film-coated sclerotia, although for sclerotia of isolate JN1, all film-coatings were effective in decreasing the weight of sclerotia subsequently produced. With isolate SB, only the C. minitans treatment reduced subsequent sclerotial production. In glasshouse and field pot bioassays with sclerotia buried in soil for 20 and 34 weeks, respectively, C. minitans completely suppressed apothecial production and no sclerotia were recovered from the C. minitans treatment pots. C. minitans spread to infect sclerotia in other treatment pots. In these bioassays, both fungicides were less effective than C. minitans, even though apothecial production was almost completely inhibited and less than 10% of sclerotia were recovered.

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“…Nevertheless, there is no information regarding the production of apothecia by strains collected from the common bean. Mylchreest and Wheeler (1987) evaluated 35 strains of S. sclerotiorum from colza in regard to production of apothecia, and they observed 100% carpogenic germination, although the time necessary for formation of stipes varied considerably.…”

Section: Discussionmentioning

confidence: 99%

Investigation of Sclerotinia sclerotiorum strains variability in Brazil

Abreu¹,

Souza²

2015

Genet. Mol. Res.

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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 experimental 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 required 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 analysis 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 aggressiveness 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 correlation 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- M.J. Abreu and E.A. Souza acterization of the pathogen population described herein will provide an important tool for promoting the development of bean cultivars resistant to white mold.

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A method for inducing apothecia from sclerotia of Sclerotinia sclerotiorum

Cited by 50 publications

References 13 publications

Use of Coniothyrium minitans transformed with the hygromycin B resistance gene to study survival and infection of Sclerotinia sclerotiorum sclerotia in soil

Use of Coniothyrium minitans transformed with the hygromycin B resistance gene to study survival and infection of Sclerotinia sclerotiorum sclerotia in soil

Biological control of Sclerotinia sclerotiorum by film‐coating Coniothyrium minitans on to sunflower seed and sclerotia

Investigation of Sclerotinia sclerotiorum strains variability in Brazil

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