Interactions between Sclerotinia sclerotiorum and Epicoccum purpurascens

1991 ◽  
Vol 69 (11) ◽  
pp. 2503-2510 ◽  
Author(s):  
Ting Zhou ◽  
R. D. Reeleder ◽  
S. A. Sparace

Sterile culture filtrates of Epicoccum purpurascens decreased severity of white mold of bean and increased pod yield when applied prior to inoculation of beans with Sclerotinia sclerotiorum. Extracts of these culture filtrates inhibited ascospore germination and mycelial growth of S. sclerotiorum. Similar inhibition of hyphal growth of S. sclerotiorum occurred when dual cultured with E. purpurascens. Contact and penetration of hyphae of S. sclerotiorum by hyphae of E. purpurascens occurred rarely on agar-covered slides and was not observed on flower petals. Inhibition of ascospore germination and germ-tube elongation occurred on agar-covered slides where E. purpurascens had been grown previously; however, addition of nutrients decreased inhibition. Colonization of bean flowers by E. purpurascens reduced white mold incidence. The degree of disease control was affected by addition of nutrients and whether or not colonized flowers were autoclaved. Key words: antifungal compounds, competition, biological control, white mold, Phaseolus.


Plant Disease ◽  
2021 ◽  
Author(s):  
Miller da Silva Lehner ◽  
Kaique Alves ◽  
Emerson Medeiros Del Ponte ◽  
Sarah Jane Pethybridge

The infection of the floral tissues of snap bean and other crops by Sclerotinia sclerotiorum, the causative agent of white mold, is by ascospores. Irrespective of the fungicide mode of action being evaluated, in vitro fungicide sensitivity tests are conducted almost exclusively using mycelial growth assays. This is likely due to difficulties and time involved in sclerotial conditioning required to produce apothecia and ascospores. The objective of this research was to compare estimates of fungicide sensitivity between mycelial growth and ascospore germination assays for S. sclerotiorum. Sensitivity assays were conducted using serial doses of three fungicides commonly used to control white mold: boscalid, fluazinam, and thiophanate-methyl. A total of 27 isolates were evaluated in replicated trials conducted for each fungicide and assay type. The effective concentration to reduce mycelial growth or ascospore germination by 50% (EC50) was estimated for each isolate, fungicide, assay type, and trial. The median EC50 values obtained from ascospore germination assays were 52.7, 10.0, and 2.7 times higher than those estimated from the mycelial growth for boscalid, fluazinam, and thiophanate-methyl, respectively. No significant correlation was found between EC50 values estimated by the two methods. These findings highlight differences that may be important in evaluating the sensitivity of S. sclerotiorum given the fungicide mode of action and how they will be used in the field.



2020 ◽  
Vol 41 (6) ◽  
pp. 2597-2612
Author(s):  
Douglas Casaroto Peitl ◽  
◽  
Ciro Hideki Sumida ◽  
Ricardo Marcelo Gonçalves ◽  
Sérgio Florentino Pascholati ◽  
...  

The antagonistic activity of 25 saprobe fungi from semiarid areas of Northeast Brazil was evaluated against Sclerotinia sclerotiorum (Lib.) de Bary (Helotiales: Sclerotiniaceae). Four fungi [Myrothecium sp. Tode (Hypocreales: Stachybotryaceae) isolate 2, Volutella minima Höhn. (Hypocreales: Nectriaceae), Phialomyces macrosporus P.C. Misra & P.H.B. Talbot (Pezizomycotina) and Dictyosporium tetraseriale Goh, Yanna & K.D. Hyde (Pleosporales: Dictyosporiaceae)] were selected and further tested their ability to inhibit mycelial growth, sclerotia formation and ascospore germination of S. sclerotiorum and to control white mold on soybean plants. V. minima and P. macrosporus filtrates at 50% effectively suppressed mycelial growth and Myrothecium sp. isolate 2 completely suppressed sclerotia formation and inhibited ascospore germination by over 95%, the same result as commercial fungicide fluazinam. Soybean plants pre-treated with Myrothecium sp. isolate 2, P. macrosporus, and V. minima and inoculated with S. sclerotiorum showed a reduction of 55.8%, 79.7%, and 83.2% of area under disease progress curve (AUDPC) of white mold, respectively, in relation to water. Collectively, these results underline the antagonistic activity of V. minima, P. macrosporus, and Myrothecium sp. isolate 2 against S. sclerotiorum and their potential as biocontrol agents of soybean white mold.



2021 ◽  
Author(s):  
Sergio E. Lemos da Silva ◽  
Kimberlly Soares Brito Bratifich ◽  
eloisa Teresa Corradini Santos

The Sclerotinia sclerotiorum is a phytopathogenic fungus that causes the White Mold of soybean, being responsible for losses of up to 100% in agricultural production. The objective of this work was to verify and analyze the effect of the raw aqueous extract (EBA) of ginger Zingiber officinalis on a strain of Sclerotinia Sclerotiorum isolated from soybean, cultivated and maintained in vitro in laboratory. The methodology consisted of a longitudinal study of the statistical analysis of the mycelial growth velocity index (MICV), after treatment of the mycelia with different concentrations of aqueous crude extract. The results showed a direct relationship between increasing concentration of EBA and a significant negative effect on the growth of scleroderia. It was possible to conclude that the antifungal activity of ginger EBA was able to inhibit the in vitro growth of Sclerotinia sclerotiorum, with potential protection of soybean crops; it can become a sustainable alternative in the control of this fungus, by decreasing the use of agrochemicals that cause damage to public health and environmental damage.



1984 ◽  
Vol 24 (125) ◽  
pp. 272 ◽  
Author(s):  
K Sitepu ◽  
HR Wallace

Fusarium lateritium inhibited ascospore germination and mycelial growth of Sclerotinia sclerotiorum in various agar media. Although the inhibition zones produced by F. lateritium were most extensive at 20�C, they were still substantial at 5 and 30�C. Sclerotinia sclerotiorum requires organic matter on the soil surface for subsequent infection of lettuce stems in pots. The introduction of F. lateritium into such pots, 7 h before introducing S. sclerotiorum, gave protection. In infected pots with organic matter, 99% of plants were infected after 6 d, whereas only 5% were infected when F. lateritium was introduced. After 14 d these values increased to 100 and 33%, respectively.



2021 ◽  
Author(s):  
Sawai Boukaew ◽  
Siriporn Yossan ◽  
Benjamas Cheirsilp ◽  
Wanida Petlamul ◽  
Poonsuk Prasertsan

Abstract The influences of culture media, temperature, and light/dark conditions on growth and antifungal activity of the three strains Streptomyces spp. against Botrytis cinerea was studied. Results of in vitro study indicated that the GYM agar and incubated at 28°C exhibited good mycelial growth and a spore mass production of the three strains of Streptomyces spp. On the other hand, the PDA and incubation at 21°C were suitable for the mycelial growth of B. cinerea . Moreover, light/dark conditions had an effect on the growth of the two strains of S. philanthi . The strains RL-1-178 and RM-1-138 of S. philanthi grown in all media and incubation temperatures tested possessed antifungal activity against B. cinerea (100% inhibition) while S. mycarofaciens showed different results on PDA (83% inhibition) and GYM (88% inhibition) with the optimum incubation temperature at 21°C. Then, the antifungal compounds in culture filtrates produced by the three antagonistic strains against B. cinerea were tested on tomato leaf. They showed a significantly higher inhibitory effect on the symptoms of blight disease on tomato leaf compared with the control. The better protection efficacy against B. cinerea on tomato leaf was observed with the culture filtrates of S. philanthi RM-1-138 (82.89% and 0.33 cm 2 lesion areas symptoms). Moreover, the antifungal compounds in the culture filtrate of S. philanthi RM-1-138, identified by GC-MS, were greatly altered relative to concentration components under different temperatures and light/dark conditions tested. Our results clearly demonstrated that the environmental factors have an influence on antifungal activity of the three strains of Streptomyces spp.



1989 ◽  
Vol 67 (6) ◽  
pp. 1775-1781 ◽  
Author(s):  
G. J. Boland ◽  
G. D. Inglis

Filamentous fungi from white bean and rapeseed flowers were isolated, characterized, and evaluated for potential as antagonists to Sclerotinia sclerotiorum (Lib.) de Bary. Various fungi were isolated from surface-sterilized petals sampled from four developmental stages ranging from freshly opened flowers to petals that had lodged on plant surfaces. Alternaria and Cladosporium spp. were the dominant mycoflora and were isolated from 65–100% of the petals that developed fungal colonies. All isolates, except one, restricted ascospore germination by the pathogen on water agar by 16–66%, and 13 of 28 isolates restricted mycelial growth on potato dextrose agar by 29–46%. Bean flowers were inoculated with spore suspensions of S. sclerotiorum and of individual antagonists and were then placed on detached bean leaves, bean seedlings, and flowering bean plants. On detached leaves in a laboratory environment, 16 of 28 isolates suppressed white mold lesion diameter by 10–100%. On bean seedlings in a growth room, 8 isolates suppressed the percentage of flowers developing lesions by 42–100%, and 12 of 13 isolates reduced mean lesion diameter by 14–100%. On flowering bean plants in a greenhouse, 6 of 11 isolates suppressed the percentage of flowers developing lesions by 14–90 %. The most disease-suppressive fungi included isolates of Drechslera sp., Epicoccum purpurascens, Fusarium graminearum, and Fusarium heterosporum; isolates of Myrothecium verrucaria and Trichoderma viride were effective in some trials.



2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Doha A. S. Gebily ◽  
Gamal A. M. Ghanem ◽  
Mona M. Ragab ◽  
Ayat M. Ali ◽  
Nour El-din K. Soliman ◽  
...  

Abstract Background White mold disease, caused by Sclerotinia sclerotiorum the devastating pathogen, attacks green beans (Phaseolus vulgaris L.) and several crops worldwide. The present investigation was carried out to introduce some antagonistic microorganisms as novel antifungal substances to be an alternative and secure method to effectively control the disease. Results Three Streptomyces species, i.e., S. griseus (MT210913 “DG5”), S. rochei (MN700192 “DG4”), and S. sampsonii (MN700191 “DG1”) were isolated, biologically, molecularly characterized, and evaluated in vitro and in vivo. Molecularly, polymerase chain reaction (PCR) amplification and nucleotide sequencing were used to characterize the pathogen and bio-agents. PCR amplification of the pathogen and Streptomyces species (bioagents) exhibited amplicons of around 535 bp and 1300 bp, respectively. The nucleotide sequence analysis of the three Streptomyces spp. indicated that S. rochei was closely related to S. griseus, and both had a distance relationship with S. sampsonii. The evaluation of bioagents was carried out against S. sclerotiorum. Reduction percentages in the mycelial growth of the pathogen ranged between 60.17 and 52.30%, indicating that S. rochie gave the highest inhibition percent. Incorporations of Streptomyces spp. culture filtrate components into culture media proved that S. sampsonii was more efficient as a bioagent in reducing mycelial growth pathogen by 84.50%. The effectiveness of the bioagent volatile compounds inhibited the pathogen growth at a rate of 54.50-72.54%, respectively, revealing that S. rochei was the highest inhibitor followed by S. griseus. The parasitic activity of Streptomyces spp. upon S. sclerotiorum showed deformation, contraction, and collapse when observed by light and scanning electron microscopy. Molecular characterization of the 3 Streptomyces spp. revealed that S. griseus was closely related to S. sampsonii (96%), secondly ranked by S. rochei (93.1%). Viability and germination of pathogen sclerotia were reduced when they dipped into the Streptomyces spore suspensions for 10, 20, and 30 days. Application of the 3 Streptomyces spp. in the field proved a great potential to control the disease. Conclusions The results suggested that the 3 Streptomyces strains and their secondary metabolites can be potential biocontrol agents and biofertilizers for controlling S. sclerotiorum, the causative agent of bean white mold disease.



2014 ◽  
Vol 6 (4) ◽  
pp. 91 ◽  
Author(s):  
Guanglong Cheng ◽  
Yun Huang ◽  
Hui Yang ◽  
Fan Liu

In order to explore the biocontrol potential of Streptomyces felleus YJ1 to sclerotinia stem rot of oilseed rape, we evaluated the effects of YJ1 as antagonistic strain on Sclerotinia sclerotiorum, including germination and formation of sclerotia, ascospore germination, mycelial growth and YJ1 colonization ability. We found the fermentation filtrate of YJ1 could inhibit sclerotia and ascospore germination and mycelial growth. In dual culture the inhibition zone diameter of YJ1 against S. sclerotiorum was 11.0 mm, and the inhibition rate reached to 80.26%. The ascospores germination was also significantly inhibited by YJ1 fermentation filtrate. In addition, YJ1 could colonize stably in rhizosphere and roots of rape. Otherwise, in the greenhouse we found the lesion would become smaller and slighter if the inoculated leaves were pretreated with YJ1 fermentation liquid. Therefore, our results strongly suggested that YJ1 was a promising biocontrol agent for control of oilseed rape sclerotinia stem rot.



Author(s):  
Md. Rabiul Islam ◽  
Ananya Prova ◽  
Md. Tanbir Rubayet ◽  
Md. Mahidul Islam Masum ◽  
Md. Motaher Hossain

A new disease causing the tan to light brown blighted stems and pods has occurred in 2.6% pea (Pisum sativum L.) plants with an average disease severity rating of 3.7 in Chapainawabganj district, Bangladesh. A fungus with white appressed mycelia and large sclerotia was consistently isolated from symptomatic tissues. The fungus formed funnel-shaped apothecia with sac-like ascus and endogenously formed ascospores. Healthy pea plants inoculated with the fungus produced typical white mold symptoms. The internal transcribed spacer sequences of the fungus were 100% similar to that recovered from an epitype of Sclerotinia sclerotiorum, considering the fungus to be the causative agent of white mold. Mycelial growth and sclerotial development of S. sclerotiorum were favored at 20°C and pH 5.0. Glucose was the best carbon sources to support hyphal growth and sclerotia formation. Bavistin and Amistar Top inhibited the radial growth of the fungus completely at the lowest concentration. In planta, foliar application of Amistar Top showed the considerable potential to control the disease at 1.0% concentration until 7 days after spraying, while Bavistin prevented infection significantly until 15 days after spraying. A large majority (70.93%) of genotypes including tested released pea cultivars were susceptible, while six genotypes (6.98%) appeared resistant to the disease. These results could be important for management strategies aiming to control the incidence of S. Sclerotinia and eliminate yield loss in pea.



Antibiotics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 664
Author(s):  
Matías Olivera ◽  
Ninoska Delgado ◽  
Fabiola Cádiz ◽  
Natalia Riquelme ◽  
Iván Montenegro ◽  
...  

Gray and summer bunch rot are important diseases of table grapes due to the high economic and environmental cost of their control with synthetic fungicides. The ability to produce antifungal compounds against the causal agents Botrytis, Aspergillus, Penicillium, and Rhizopus of two microorganisms isolated from table grapes and identified as Hanseniaspora osmophila and Gluconobacter cerinus was evaluated. In dual cultures, both biocontrol agents (together and separately) inhibited in vitro mycelial growth of these pathogens. To identify the compounds responsible for the inhibitory effect, extractions were carried out with organic solvents from biocontrol agents separately. Through dual cultures with pathogens and pure extracts, only the hexane extract from H. osmophila showed an inhibitory effect against Botrytis cinerea. To further identify these compounds, the direct bioautography technique was used. This technique made it possible to determine the band displaying antifungal activity at Rf = 0.05–0.2. The compounds present in this band were identified by GC-MS and compared to the NIST library. The most abundant compounds, not previously reported, corresponded to alkanes, ketones, alcohols, and terpenoids. H. osmophila and G. cerinus have the potential to control the causal agents of gray and summer bunch rot of table grapes.



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