scholarly journals Antifungal activity of Xenorhabdus spp. and Photorhabdus spp. against the soybean pathogenic Sclerotinia sclerotiorum

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Julie G. Chacón-Orozco ◽  
César Bueno ◽  
David I. Shapiro-Ilan ◽  
Selcuk Hazir ◽  
Luís G. Leite ◽  
...  

AbstractThe fungus, Sclerotinia sclerotiorum, causes white mold disease and infects a broad spectrum of host plants (> 500), including soybean with yield losses of up to 70%. Biological control is a potential alternative for management of this severe plant pathogen, and relative to chemical fungicides, provides broad benefits to the environment, farmers and consumers. The symbiotic bacteria of entomopathogenic nematodes, Xenorhabdus spp. and Photorhabdus spp., are characterized by the production of antimicrobial compounds, which could serve as potential sources for new bio-fungicides. The objectives of this study were to assess cell-free supernatants (CFS) of 16 strains of these bacteria cultures on S. sclerotiorum mycelium growth; assess the volatiles of X. szentirmaii cultures on the fungus mycelium and sclerotium inhibition; and evaluate the X. szentirmaii cultures as well as their CFS on the protection of soybean seeds against the white mold disease. Among the 16 strains, the CFS of X. szentirmaii showed the highest fungicidal effect on growth of S. sclerotiorum. The CFS of X. szentirmaii inhibited > 98% of fungus growth from mycelium and sclerotia, whereas the volatiles generated by the bacterium culture inhibited to 100% of fungus growth and 100% of sclerotia production. The bacterial culture diluted to 33% in water and coated on soybean seeds inhibited S. sclerotiorum and protected soybean plants, allowing 78.3% of seed germination and 56.6% of plant development. Our findings indicate potential for a safe and novel control method for S. sclerotiorum in soybean. Moreover, this is the first study to indicate that volatile organic compounds from Xenorhabdus spp. can be used in plant disease suppression.

2017 ◽  
Vol 52 (12) ◽  
pp. 1140-1148 ◽  
Author(s):  
Patrícia Elias Haddad ◽  
Luis Garrigós Leite ◽  
Cleusa Maria Mantovanello Lucon ◽  
Ricardo Harakava

Abstract: The objective of this work was to evaluate, in vitro and in vivo, the potential of Trichoderma spp. strains to control Sclerotinia sclerotiorum in soybeans (Glycine max) and to perform the molecular identification of the best perfoming strains. The effect of 120 strains of Trichoderma spp. on the viability of S. sclerotiorum sclerotia was evaluated in vitro through immersion in suspension of conidia from the antagonists and plating in culture medium. The best performing strains were evaluated in vivo, in a greenhouse, for control of the pathogen inoculated on 'Pintado' soybean seeds and plants. Of the 120 strains tested in vitro, 22 strains of Trichoderma spp. caused 100% inhibition of sclerotia germination. In the greenhouse, five strains inhibited the negative effect of the pathogen on seed germination and two strains increased in up to 67% plant dry matter. The best performing strains were identified as T. koningiopsis (3 strains), T. asperelloides (3), T. atroviride (2), and T. virens (1). Trichoderma strains are able to protect soybean plants from the harmful effect of S. sclerotiorum and, at the same time, they can promote the growth of the aerial part in greenhouse conditions.


2018 ◽  
Vol 28 (2) ◽  
pp. 142-156 ◽  
Author(s):  
Ciro H. Sumida ◽  
Juliana F. S. Daniel ◽  
Ana Paula C. S. Araujod ◽  
Douglas C. Peitl ◽  
Lucas M. Abreu ◽  
...  

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 ◽  
pp. 104685
Author(s):  
Natálie Martins Alves ◽  
Rafaela Araújo Guimarães ◽  
Sarah Silva Costa Guimarães ◽  
Amanda Frausino Faria ◽  
Ítalo Augusto Férrer Melo Santos ◽  
...  

2009 ◽  
Vol 89 (4) ◽  
pp. 755-762 ◽  
Author(s):  
H Terán ◽  
S P Singh

White mold (WM) caused by Sclerotinia sclerotiorum (Lib.) de Bary is the most devastating disease of common bean (dry and snap or garden bean) (Phaseolus vulgaris L.) in North America. The use of a reliable screening method (SM) in common bean is crucial to improve physiological resistance to WM. The objective of this study was to compare the efficacy of three SM to identify physiological resistance in dry bean genotypes with different evolutionary origins and levels of resistance. Screening methods tested were: (i) the modified straw test or cut–stem (CSM); (ii) infected bean flower (IFL); and (iii) infected oat seed (IOS). A 195, ICA Bunsi, Othello, and VCW 54 dry bean were tested with the three SM. The experimental design was a split plot in randomized complete blocks with three replications in 2007 and 2008. Two independent inoculations 1 wk apart for each SM were made. The WM reaction was scored at 16, 23, and 33 d post-inoculation (DPI) using a 1 to 9 scale. There were highly significant differences between SM and its interaction with years. The CSM and IFL were the most consistent and highly correlated (r > 0.70, P < 0.01). Interspecific breeding line VCW 54 consistently had the highest WM resistance across years, SM, and evaluation dates, followed by A 195. White mold scores increased with delayed evaluations. Thus, CSM or IFL with disease assessed 33 DPI should be used for identifying common bean genotypes with high levels of physiological resistance to WM.Key words: Common bean, growth habit, race Mesoamerica, race Nueva Granada, Phaseolus vulgaris, Sclerotinia sclerotiorum


Author(s):  
Md. Rabiul Islam ◽  
Abdul Mannan Akanda ◽  
Md. Mofazzal Hossain ◽  
Md. Motaher Hossain

2015 ◽  
Vol 41 (4) ◽  
pp. 251-255 ◽  
Author(s):  
Daiane Cristina Martins Barros ◽  
Inês Cristina de Batista Fonseca ◽  
Maria Isabel Balbi-Peña ◽  
Sérgio Florentino Pascholati ◽  
Douglas Casaroto Peitl

ABSTRACTThe incidence and the levels of yield loss caused by the white mold of soybean (caused by the fungus Sclerotinia sclerotiorum) have increased in areas of higher altitude at Cerrado and Southern Brazil, causing yield losses of up to 60%. The aim of this study was to select saprobic fungi with the potential to control the white mold of soybean. First, in vitroantagonism screening was carried out to test eight saprobic fungi against S. sclerotiorum. Assessment of S. sclerotiorum mycelial growth was done at four and seven days after its placement on the culture medium. The isolate showing greatest antagonistic effect in all tests/assessments was Myrothecium sp. An in vivo experiment was conducted in a greenhouse and growth chamber, where plants previously treated with eight saprobic fungi were artificially inoculated with S. sclerotiorum. The fungal culture medium (potato-dextrose) and the commercial resistance inducer acibenzolar-S-methyl were used as controls. In the in vivotests, severity of the white mold was assessed at 8, 14 and 21 days after inoculation. The highest reduction percentage in the lesion length was observed for the treatment with Myrothecium sp. (70%), which has the greater potential to be used as biocontrol agent of soybean under the conditions of this experiment.


Plant Disease ◽  
2007 ◽  
Vol 91 (10) ◽  
pp. 1360-1360
Author(s):  
A. Garibaldi ◽  
A. Minuto ◽  
M. L. Gullino

Oreganum vulgare (wild marjoram) and Taraxacum officinale (dandelion) plants with culinary and medicinal uses are grown in the field and as potted plants in Liguria in northern Italy. In the spring of 2006, extensive chlorosis was observed on both crops on commercial farms. Economic losses were low. Symptoms included foliar necrosis and a watery decay of the stem at the soil level. Necrotic tissues became covered with a whitish mycelium that produced dark sclerotia. Eventually, affected plants wilted and died. Samples of diseased stem tissue were surface sterilized for 1 min in 1% NaOCl and plated on potato dextrose agar (PDA) amended with 100 mg/l of streptomycin sulfate. Sclerotinia sclerotiorum (Lib.) de Bary (1) was consistently recovered from diseased stem pieces. Sclerotia from infected O. vulgare plants measured 1.8 to 3.4 × 1.8 to 6.1 (average 2.5 to 3.6) mm. Sclerotia from these isolates measured 1.3 to 4.7 × 1.6 to 6.1 (average 2.7 to 3.4) mm on PDA. Sclerotia from infected T. officinale plants measured 1.8 to 3.4 × 1.8 to 6.1 (average 2.5 to 3.6) mm. Sclerotia from these isolates measured 1.7 to 5.2 × 2.0 to 5.7 (average 3.3 to 3.8) mm on PDA. Pathogenicity of three isolates obtained from O. vulgare and three isolates from T. officinale was confirmed on each host. Inoculum consisted of 1 cm2 of mycelial plugs excised from a 10-day-old PDA culture of each isolate. Plants were inoculated by placing a mycelial plug on the soil surface around the base of each plant. Ten plants were inoculated per isolate and an equal number of noninoculated plants served as controls. Plants were incubated at 10 to 27°C (average 18°C) and watered as needed. Pathogenicity tests were repeated once. All inoculated plants developed chlorosis within 12 to 18 days, followed by the appearance of white mycelium and sclerotia, and eventually wilt. Control plants remained symptomless. S. sclerotiorum was reisolated from inoculated plants of both hosts. To our knowledge, this is the first report of white mold on O. vulgare in Italy as well as worldwide and the first report of white mold on T. officinale in Italy. S. sclerotiorum is a well known pathogen of T. officinale (2) and its use as a mycoherbicide has been proposed (3). References: (1) N. F. Buchwald. Page 75. Den. Kgl. Veterin.er-og Landbohojskoles Aarsskrift, 1949. (2) D. M. McLean. Plant Dis. Rep. 35:162, 1951 (3) G. E. Riddle et al. Weed Sci. 39:109, 1991.


2016 ◽  
Vol 3 ◽  
pp. 61
Author(s):  
R. Ibañez

The assay was conducted in Pelotas, Rio Grande do Sul-Brasil, to compare the effect of used engine oil with to paraquat (Gramoxone) applied during the physiological maturition of soybean seeds (Glicyne max (L.) Merrill), Bragg variety. The oil doses were 5.3, 8.5 and 12 l/ha. The desiccation intensity was determined and 30 pods per plot were periodically collected to follow the humidity content of the seeds, to 18%. The humidity was later reduced to 10.5 +0.5 and 2.0 kg of seeds were stored, in cotton bags,during 6 months under the environmental conditions at the Centro de Entrenamiento de Semillas of the Federal University of Pelotas. The seeds were subjected to germination, vigor and phytosanitary tests at harvest time and after 3 and 6 months of storage. Under the conditions of this trial, the doses of 12 l/ha of oil and 2 l/ha of paraquat: a) act as desiccants for soybean plants, b) favors the production of seeds with better viability and vigor after 6 months of storage and c) guarantied better sanitary seed quality after 6 months of storage.


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