In vitro inhibition of plant pathogens by Bacillus subtilis and Enterobacter aerogenes and in vivo control of two postharvest cherry diseases

1986 ◽  
Vol 32 (12) ◽  
pp. 963-967 ◽  
Author(s):  
R. S. Utkhede ◽  
P. L. Sholberg

Twenty-one isolates of the bacterium Bacillus subtilis and one of Enterobacter aerogenes were tested on agar for antagonism to Alternaria alternata, Armillariella mellea, Botrytis allii, Botrytis cinerea, Colletotrichum lindemuthianum, Monilinia fructicola, Penicillium expansum, Phytophthora cactorum, Pythium ultimum, Rhizoctonia solani, Sclerotinia sclerotiorum, Sclerotium cepivorum, Verticillium dahliae, and Venturia inequalis, causal organisms of many plant diseases. Enterobacter aerogenes was antagonisic to all of the pathogenic fungi tested except Verticillium dahliae and Armillariella mellea. Similarly, Bacillus subtilis was antagonistic to all of the pathogenic fungi tested except Pythium ultimum. When Enterobacter aerogenes and Bacillus subtilis were tested in vivo on cherry fruit for control of postharvest brown rot and alternaria rot, Enterobacter aerogenes was ineffective. Eleven isolates of Bacillus subtilis provided effective alternaria rot control and 15 isolates provided brown rot control which ranked with the best fungicide control.

2021 ◽  
Vol 33 (2) ◽  
pp. 38-44
Author(s):  
Ariunaa Saraadanbazar ◽  
Byambasuren Mijidsuren ◽  
Battur Banzragch

The objective of this study was the isolation and characterization of Bacillus subtilis local strains from the soil in Mongolia. These local strains of B. subtilis are showed to have high antagonistic activities against some plant pathogenic fungi and bacteria. Six strains of B. subtilis were isolated and characterized morphologically, physiologically and biochemically according the Bergey’s Manual of Systematic Bacteriology. In order to identify species of the isolated strains, we amplified and sequenced 16S rRNA gene, essential funtinal genes bmyB, spoVG and srfAA, which are related to antagonistic activity of these strains. The sequences were aligned using CLASTALW multiple sequence alignment tool. Phylogenetic tree was drawn according to Maximum likelihood”method and “Tamura-Nei” model using “MEGA-X version 10.2.6 program. Among all isolates of B. subtilis MN99 and 7/24 strains had higher antagonist activity against plant diseases. According to partial sequence of srfAA (620bp) gene of MN99, the local strain belongs to B. subtilis and partial sequence of bmyB (370bp), spoVG (22bp) gene of MN7/24 strain showed that the it belongs to B. atrophaeus species. All local strains of B. subtilis had bacillomycin synthesis gene, and B. subtilis MN99 strain had only surfactine synthesis gene, while did not have spore formation and hemolysis gene SpoVG.


2020 ◽  
Vol 12 (12) ◽  
pp. 144
Author(s):  
M. E. N. Ferreira ◽  
C. F. Pinto ◽  
R. R. de Sena ◽  
J. G. de Mendoça Neto ◽  
C. R. Lobo ◽  
...  

Fungi are among the main agents of plant diseases, being responsible for major losses in agriculture. The control of these microorganisms carried out using chemical compounds and numerous cases of resistance have already been observed, which makes it necessary to search for alternative methods of management of these pathogens. Therefore, the aim of this study, to evaluate the antifungal potential in plants. Twenty-four (24) plant extracts were tested for their antifungal potential against five plant pathogenic fungi: Sclerotinia sclerotiorum (Ss), Stromatinia cepivora (Sc), Fusarium oxysporum (Fox), Colletotrichum gloesporioides (Cg) and Verticillium dahlia (Vd). For the evaluation of the fungicidal potential, plant extracts were prepared by liquefying the plants in distilled water. The extracts were incorporated into PDA (Potato-Dextrose-Agar) culture medium to a final concentration of 35% and autoclaved. Then, PDA discs colonized by the aforementioned fungi were added to the center of each plate with the respective treatments (plant extracts). When all control treatments (PDA medium without plant extract) had colonized the entire Petri dish, the diameters of the fungal colonies were measured to calculate the Mycelial Growth Inhibition Index (MGI). Tests showed that all these plant extracts have some antifungal activity, ranging from 0 to 100% inhibition. In general, extracts of basil, lavender, guaco, rue, toxic cassava and black plum were the ones that stood out, with MGIs above 50%. New studies are being conducted to evaluate the activity of plant extracts without autoclaving, inhibition of sclerotia formation, to determine the minimum inhibitory concentration, as well as other parts of plants like roots and seeds, mixtures of plant extracts and in vivo antagonism tests.


Plants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1113
Author(s):  
Anastasios Samaras ◽  
Efstathios Roumeliotis ◽  
Panagiota Ntasiou ◽  
George Karaoglanidis

Bacillus subtilis MBI600 (Bs MBI600) is a recently commercialized plant-growth-promoting rhizobacterium (PGPR). In this study, we investigated the effects of Bs MBI600 on the growth of tomato and its biocontrol efficacy against three main soilborne tomato pathogens (Rhizoctonia solani, Pythium ultimum, and Fusarium oxysporum f.sp. radicis-lycopersici-Forl). Furthermore, the root colonization ability of the Bs MBI600 strain on tomato roots was analyzed in vivo with a yellow fluorescence protein (yfp)-labeled strain, revealing strong colonization ability, which was affected by the root growth substrate. The application of Bs MBI600 on tomato plants resulted in significant increases in shoot and root lengths. Transcriptional activation of two auxin-related genes (SiPin6 and SiLax4) was observed. Single applications of Bs MBI600 on inoculated tomato plants with pathogens revealed satisfactory control efficacy compared to chemical treatment. Transcriptomic analysis of defense-related genes used as markers of the salicylic acid (SA) signaling pathway (PR-1A and GLUA) or jasmonic acid/ethylene (JA/ET) signaling pathway (CHI3, LOXD, and PAL) showed increased transcription patterns in tomato plants treated with Bs MBI600 or Forl. These results indicate the biochemical and molecular mechanisms that are activated after the application of Bs MBI600 on tomato plants and suggest that induction of systemic resistance (ISR) occurred.


2011 ◽  
Vol 39 (No. 2) ◽  
pp. 70-77 ◽  
Author(s):  
R.N. Okigbo ◽  
M.I. Osuinde

The incidence of fungal leaf spot diseases on mango (Mangifera indica) in Southeastern Nigeria and application of a biological control measure was investigated. The survey proved that the incidence of leaf spot diseases was greatest in Umuahia (72%) followed by Okigwe and Ojoto, with a peak at the beginning of the rainy season (February–March). Three pathogenic fungi, Pestalotiopsis mangiferae, Botryodiplodia theobromae and Macrophoma mangiferae, were isolated from leaf spots. Other fungi, Fusariella spp., which are well known saprophytes of dead plant materials, and the fungus Meliola sp., were also isolated from diseased leaves. Pathogenicity tests showed that P. mangiferae, B. theobromae and M. mangiferae were the causal agents of the fungal leaf spot diseases. Symptoms developed 5 weeks after inoculation of healthy leaves. Bacillus subtilis NCIB 3610, isolated from soil under a mango tree, inhibited P. mangiferae, B. theobromae and M. mangiferae by 57%, 61% and 58% respectively on agar plates. Also, in in vivo experiments the symptoms were considerably reduced in the field by the application of the antagonist. The importance of the biological control method for rural mango farmers is emphasised.  


2016 ◽  
Vol 5 (2) ◽  
pp. 73-80
Author(s):  
Khadija N. Hassan ◽  
Josphat C. Matasyoh ◽  
Marc Stadler

Phytopathogens are known to be the leading cause of important plant diseases which result in significant losses in agricultural crops. The need to maintain the level of yield both quantitatively and qualitatively is vital in order to curb the losses. So far there has been a positive advance recognized in research to the use of tropical fungi as biocontrol agents. The objective of this study was to screen for antagonistic tropical fungi against selected phytopathogens of maize (Zea mays L.) and beans (Phaseolus vulgaris L.) namely Fusarium graminearum, Fusarium moniliforme, Pythium ultimum, and Colletotrichum lindemuthianum in vitro. A total of 87 tropical fungi isolates were collected from Kakamega tropical rainforest, Kenya. Dual culture experiment was carried out to screen the tropical fungi against the selected phytopathogens. The bioassay was performed in a completely randomised design in triplicate and the inhibition zones recorded after every week for three weeks. Differential biocontrol ability among nine tropical fungi was noticed against F. moniliforme with the percentage inhibition increasing over time. Fusarium solani was the most active antagonist with an inhibition of 64% while Phaeomarasmius sp. had the lowest activity of 19.1% against F. moniliforme. Epicoccum sp. inhibited the mycelial growth of P. ultimum by 38% and also inhibited C. lindemuthianum by 58%. None of the fungal antagonists inhibited the mycelial growth of F. graminearum. The outcome of this study indicates that tropical fungi can be used as biocontrol agents and can be further explored and developed into effective fungicides for management of phytopathogens.


Phytotaxa ◽  
2016 ◽  
Vol 278 (3) ◽  
pp. 212
Author(s):  
ZUCHEN LIU ◽  
UWE BRAUN ◽  
PEDRO W. CROUS ◽  
JING SI ◽  
YING ZHANG

Cercosporoid fungi include a large number of mostly plant pathogenic fungi with a wide geographic distribution, being usually associated with leaf spots on a broad range of plant hosts. Here we initiate a series of studies on Chinese cercosporoid fungi, focussing on the identification of some common, rare and new plant diseases caused by these leaf-spotting ascomycetes. The aim of the series is to resolve the taxonomy and DNA phylogeny of this important group of phytopathogens in China. In this study, nine isolates of cercosporoid fungi were collected from five host species. Partial nucleotide sequence data of four gene loci (ITS, LSU, TUB and tef1-α rDNA) were generated for all isolates. Based on morphological characters in vivo and in vitro and phylogenetic data, a new species, Pseudocercospora pauciseptata (on living leaves of Pyracantha fortuneana), is introduced including a detailed description, illustration and comparison with similar species. In addition, Passalora circumscissa, Pseudocercospora cercidis-chinensis, P. lindericola, and P. prunicola are described, illustrated and phylogenetically characterized. Cerasus pseudocerasus represents a new host record for Passalora circumscissa in China, while Lindera reflexa is a new host for P. lindericola.


Biology ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 492
Author(s):  
Hernando José Bolivar-Anillo ◽  
Victoria E. González-Rodríguez ◽  
Jesús M. Cantoral ◽  
Darío García-Sánchez ◽  
Isidro G. Collado ◽  
...  

Plant diseases are one of the main factors responsible for food loss in the world, and 20–40% of such loss is caused by pathogenic infections. Botrytis cinerea is the most widely studied necrotrophic phytopathogenic fungus. It is responsible for incalculable economic losses due to the large number of host plants affected. Today, B. cinerea is controlled mainly by synthetic fungicides whose frequent application increases risk of resistance, thus making them unsustainable in terms of the environment and human health. In the search for new alternatives for the biocontrol of this pathogen, the use of endophytic microorganisms and their metabolites has gained momentum in recent years. In this work, we isolated endophytic bacteria from Zea mays cultivated in Colombia. Several strains of Bacillus subtilis, isolated and characterized in this work, exhibited growth inhibition against B. cinerea of more than 40% in in vitro cultures. These strains were characterized by studying several of their biochemical properties, such as production of lipopeptides, potassium solubilization, proteolytic and amylolytic capacity, production of siderophores, biofilm assays, and so on. We also analyzed: (i) its capacity to promote maize growth (Zea mays) in vivo, and (ii) its capacity to biocontrol B. cinerea during in vivo infection in plants (Phaseolus vulgaris).


2020 ◽  
Vol 21 (5) ◽  
pp. 438-450
Author(s):  
Ramya Ramchandran ◽  
Swetha Ramesh ◽  
Anviksha A ◽  
RamLal Thakur ◽  
Arunaloke Chakrabarti ◽  
...  

Background:: Antifungal cyclic lipopeptides, bioactive metabolites produced by many species of the genus Bacillus, are promising alternatives to synthetic fungicides and antibiotics for the biocontrol of human pathogenic fungi. In a previous study, the co- production of five antifungal lipopeptides homologues (designated as AF1, AF2, AF3, AF4 and AF5) by the producer strain Bacillus subtilis RLID 12.1 using unoptimized medium was reported; though the two homologues AF3 and AF5 differed by 14 Da and in fatty acid chain length were found effective in antifungal action, the production/ yield rate of these two lipopeptides determined by High-Performance Liquid Chromatography was less in the unoptimized media. Methods:: In this study, the production/yield enhancement of the two compounds AF3 and AF5 was specifically targeted. Following the statistical optimization (Plackett-Burman and Box-Behnken designs) of media formulation, temperature and growth conditions, the production of AF3 and AF5 was improved by about 25.8- and 7.4-folds, respectively under static conditions. Results:: To boost the production of these two homologous lipopeptides in the optimized media, heat-inactivated Candida albicans cells were used as a supplement resulting in 34- and 14-fold increase of AF3 and AF5, respectively. Four clinical Candida auris isolates had AF3 and AF5 MICs (100 % inhibition) ranging between 4 and 16 μg/ml indicating the lipopeptide’s clinical potential. To determine the in vitro pharmacodynamic potential of AF3 and AF5, time-kill assays were conducted which showed that AF3 (at 4X and 8X concentrations) at 48h exhibited mean log reductions of 2.31 and 3.14 CFU/ml of C. albicans SC 5314, respectively whereas AF5 at 8X concentration showed a mean log reduction of 2.14 CFU/ml. Conclusion:: With the increasing threat of multidrug-resistant yeasts and fungi, these antifungal lipopeptides produced by optimized method promise to aid in the development of novel antifungal that targets disease-causing fungi with improved efficacy.


2021 ◽  
Vol 7 (3) ◽  
pp. 202
Author(s):  
Johannes Delgado-Ospina ◽  
Junior Bernardo Molina-Hernández ◽  
Clemencia Chaves-López ◽  
Gianfranco Romanazzi ◽  
Antonello Paparella

Background: The role of fungi in cocoa crops is mainly associated with plant diseases and contamination of harvest with unwanted metabolites such as mycotoxins that can reach the final consumer. However, in recent years there has been interest in discovering other existing interactions in the environment that may be beneficial, such as antagonism, commensalism, and the production of specific enzymes, among others. Scope and approach: This review summarizes the different fungi species involved in cocoa production and the cocoa supply chain. In particular, it examines the presence of fungal species during cultivation, harvest, fermentation, drying, and storage, emphasizing the factors that possibly influence their prevalence in the different stages of production and the health risks associated with the production of mycotoxins in the light of recent literature. Key findings and conclusion: Fungi associated with the cocoa production chain have many different roles. They have evolved in a varied range of ecosystems in close association with plants and various habitats, affecting nearly all the cocoa chain steps. Reports of the isolation of 60 genera of fungi were found, of which only 19 were involved in several stages. Although endophytic fungi can help control some diseases caused by pathogenic fungi, climate change, with increased rain and temperatures, together with intensified exchanges, can favour most of these fungal infections, and the presence of highly aggressive new fungal genotypes increasing the concern of mycotoxin production. For this reason, mitigation strategies need to be determined to prevent the spread of disease-causing fungi and preserve beneficial ones.


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