scholarly journals In vitro and in vivo Assay for Assessment of the Biological Control Potential of Streptomyces sp. KT

2017 ◽  
Vol 7 (1) ◽  
pp. 10
Author(s):  
Tatsuya Ohike ◽  
Minori Maeda ◽  
Tetsuya Matsukawa ◽  
Masahiro Okanami ◽  
Shin’ichiro Kajiyama ◽  
...  

Rhizoctonia solani is fungal plant pathogen that infects many different host plants. Recently, biological control agents that are friendly to the environment and ecosystems have attracted much attention as an alternative to the use of chemical fungicide which have been used worldwide to control soil borne pathogens including R. solani. In this study, 53 strains of actinomycetes isolated from environmental soils, and antifungal activities of them were assessed by the dual culture assay. Strain KT showed strong inhibitory activities against 8 phytopathogenic fungi. A great suppressive effect on R. solani growth was observed in the inoculation test of plants using cucumber and chin-geng-sai. In addition, infection of Bipolaris oryzae also could be suppressed in the detached leaf assay using oats. As a result of genetic analysis, it was shown that KT was a species closely related to Streptomyces lavenduligriseus NRRL B-3173T. However, as far as we know, there is no report for biological control agents using S. lavenduligriseus. This study suggests that the strain KT may useful as biological control agents to suppress various crop diseases.

Agronomy ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 891
Author(s):  
Mila Santos ◽  
Fernando Diánez ◽  
Alejandro Moreno-Gavíra ◽  
Brenda Sánchez-Montesinos ◽  
Francisco J. Gea

A study was conducted to explore the efficacy of potential biocontrol agent Cladobotryum mycophilum against different phytopathogenic fungi. The growth rates of 24 isolates of C. mycophilum were determined, and their antagonistic activity was analysed in vitro and in vivo against Botrytis cinerea, Fusarium oxysporum f. sp. radicis-lycopersici, Fusarium oxysporum f.sp. cucumerinum, Fusarium solani, Phytophthora parasitica, Phytophthora capsici, Pythium aphanidermatum and Mycosphaerella melonis. Most isolates grow rapidly, reaching the opposite end of the Petri dish within 72–96 h. Under dual-culture assays, C. mycophilum showed antagonistic activity in vitro against all phytopathogenic fungi tested, with mycelial growth inhibition ranging from 30 to 90% against all the different phytopathogens tested. Similarly, of all the selected isolates, CL60A, CL17A and CL18A significantly (p < 0.05) reduced the disease incidence and severity in the plant assays compared to the controls for the different pathosystems studied. Based on these results, we conclude that C. mycophilum can be considered as a potential biological control agent in agriculture. This is the first study of Cladobotryum mycophilum as a biological control agent for different diseases caused by highly relevant phytopathogens in horticulture.


2018 ◽  
Vol 10 (3) ◽  
pp. 54
Author(s):  
Tatsuya Ohike ◽  
Tetsuya Matsukawa ◽  
Masahiro Okanami ◽  
Shin’ichiro Kajiyama ◽  
Takashi Ano

Fifty actinomycetes were isolated from fifteen soil samples and were screened for their antagonism against fungal plant pathogens by dual culture assay, and one of the strain named AR10 was shown to be most effective in suppression of growth of plant pathogen. An antifungal compound of AR10 was extracted, and purified by TLC and HPLC. As a result of NMR and LC-MS analysis, the antifungal compound was identified as albocycline. AR10 suppressed Rhizoctonia damping-off of cucumber in infection control assay. The 16S rDNA sequence of AR10 shows high sequence similarity to those of genus Streptomyces, and the closest similarity was found in the sequence of S. lanatus NBRC 12787T with 98.7% similarity. However, the production of albocycline in Streptomyces closely related to AR10 in the phylogenetic tree has not been reported. Our finding suggests that AR10 can be a candidate for biological control agents.


2021 ◽  
Author(s):  
Robert Blundell ◽  
Molly Arreguin ◽  
Akif Eskalen

SummaryGrapevine trunk diseases (GTDs) threaten the economic sustainability of viticulture worldwide causing a significant reduction of both yields and quality of grapes. Biological control presents a promising sustainable alternative to cultural and chemical methods to mitigate the effects of pathogens causing GTDs, including Botryosphaeria dieback, Eutypa dieback and Esca. This study aimed to identify naturally occurring potential biological control agents from a variety of grapevine tissues, including sap, cane and pith and evaluate their antagonistic activity against selected fungal pathogens responsible for GTDs in vitro. Bacterial and fungal isolates were preliminary screened in vitro to determine their antifungal activity via a dual culture assay against Neofusicoccum parvum and Eutypa lata. Among the fungal isolates, Trichoderma spp. inhibited E. lata mycelial growth up to 64% and N. parvum mycelial growth up to 73% with overgrowth and stopped growth being the likely antagonistic mechanisms. Among the bacterial isolates, Bacillus spp. inhibited E. lata mycelial growth up to 20% and N. parvum mycelial growth up to 40%. Select antagonistic isolates of Trichoderma, Bacillus and Aureobasidium spp. were subject to further dual culture antifungal analysis against Diplodia seriata and Diaporthe ampelina, with Trichoderma isolates consistently causing the greatest inhibition. Volatile organic compound antifungal analysis revealed that these Trichoderma isolates resulted significantly inhibited mycelial growth of N. parvum, E. lata and D. ampelina causing up to 20.11%, 60.55% and 70.9% inhibition respectively (P≤0.05). Multilocus sequence analysis revealed that the Trichoderma isolates are most closely related to Trichoderma asperellum and Trichoderma hamatum. This study identifies grapevine sap as a novel source of potential biological control agents for control of GTDs to support existing efforts to control GTDs. Further testing will be necessary to fully characterize these microbes mode of antagonism and assess their efficacy for pruning wound protection in planta.


HortScience ◽  
2020 ◽  
Vol 55 (7) ◽  
pp. 988-994
Author(s):  
Jacqueline Joshua ◽  
Margaret T. Mmbaga

Fungi isolated from snap bean roots and rhizosphere soil where fungicides are not used included Fusarium oxysporum, Fusarium equiseti, Fusarium subglutinans, Fusarium camptoceras, Fusarium chlamydosporum, Fusarium verticillioides, Fusarium proliferatum, Fusarium acuminatum, Fusarium solani, Peyronellaea pinodella, Macrophomina phaseolina, and Glomerella guttata. Only P. pinodella, M. phaseolina, and F. oxysporum were isolated on symptomatic plants. These soilborne fungi are common pathogens of diverse host plants. Pathogenicity tests under controlled environment demonstrated that these fungi were pathogenic on snap beans. Subsequently, bacterial endophytes isolated from snap bean roots, papaya roots and stems, and dogwood stems were evaluated as potential biological control agents against these diverse fungi. All bacteria isolated, including Bacillus vallismortis (PS), Bacillus amyloliquefaciens (Psl), Bacillus subtilis (Prt), Bacillus thuringiensis (Y and IMC8), Enterobacter sp. (E), Stenotrophomonas sp. (B17A), and Serratia sp. (B17B) suppressed growth of the fungal pathogens in vitro and formed clear inhibition zones in petri dish dual cultures. Growth media taken from the inhibition zones suppressed growth of the fungal pathogens in the absence of the bacterial cells, suggesting that the bacteria released unidentified antagonistic biochemical substances into the media. This study constitutes an initial screening of endophytes as biological control agents against diverse fungal pathogens and forms a basis for the discovery of novel strains that can be further developed and integrated into disease management systems for diverse fungal pathogens. Isolates B. vallismortis (PS), B. amyloliquefaciens (Psl), B. subtilis (Prt), and B. thuringiensis (Y IMC8) exhibited the best performance as potential biological control agents paving the way for larger-scale in vivo studies and characterization of their interactions with fungal pathogens.


Horticulturae ◽  
2021 ◽  
Vol 7 (7) ◽  
pp. 169
Author(s):  
Alessandra Di Francesco ◽  
Michele Di Foggia ◽  
Alessio Vittoria ◽  
Elena Baraldi

Cadophora luteo-olivacea represents a critical problem for kiwifruit in the post-harvest phase, mainly for its little note epidemiology. The study presented some results about the possibility of preserving kiwifruit from skin pitting symptoms using alternative methods to fungicides. By in vitro assays, antagonist mechanisms of action against pathogen isolates were tested. Trichoderma harzianum (Th1) showed the highest inhibitory activity against C. luteo-olivacea isolates by volatile, non-volatile, and by dual culture assay, displaying an inhibition respectively by 90%, 70.6%, and 78.8%, and with respect to Aureobasidium pullulans (L1 and L8) by 23.3% and 25.8%, 50% and 34.7%, and 22.5% and 23.6%, respectively. Further, the sensitivity on CFU and mycelial growth of C. luteo-olivacea isolates to fludioxonil, and CaCl2 was tested, displaying interesting EC50 values (0.36 and 0.92 g L−1, 22.5 g L−1, respectively). The effect of Brassica nigra defatted meal was tested as biofumigation assays and through FT-IR (Fourier-Transform Infrared) spectroscopy. The above-mentioned treatments were applied in vivo to evaluate their efficacy on kiwifruits. Our data demonstrated that alternative solutions could be considered to control postharvest pathogens such as C. luteo-olivacea.


2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Mehmet Aydoğdu ◽  
Serap Melike Sülü ◽  
İlker Kurbetli ◽  
Görkem Sülü

Abstract Background Aggressive biotype (Trichoderma aggressivum f. aggressivum) of green mold is one of the main biotic factors limiting button mushroom (Agaricus bisporus) cultivation. Due to issues such as fungicide resistance, cost, and adverse effects, biological control seems to be an applicable management method against the green mold in button mushroom cultivation. Results The objective of the study was to assess biological control of green mold in button mushroom cultivation. Five native bacterial isolates from mushroom compost and 3 commercial biological preparations were tested against two isolates of T. aggressivum f. aggressivum. Dual culture tests were used in vitro experiments. In vivo, compost and casing soil experiments were conducted by comparing yield values of treated plots with negative and positive controls. In vitro, the bacterial isolates inhibited mycelial growth of isolates of T. aggressivum f. aggressivum and A. bisporus up to 46.60 and 56.94%, respectively. In vivo, in the compost experiment, compared with positive control plots, bacterial isolate MSG-5 (Bacillus subtilis) caused the highest yield increase (40.56%) in the treatments. In the casing soil experiment, commercial biological preparation Tic-3 (Ampelomyces quisqualis) caused the highest yield increase (36.15%) in the treated plots. Compared with positive and negative controls, all the treatments caused 30.23% increase but 4.86% decrease in yield of A. bisporus in the compost experiment, respectively. However, they caused 20.25% increase but 17.33% decrease in the yield of A. bisporus in the casing soil experiment, respectively. Conclusions Results suggested that biological control of the green mold in compost can be more efficient than casing soil in button mushroom cultivation.


2020 ◽  
Vol 9 (1) ◽  
pp. 29-42
Author(s):  
Sabrine Mannai ◽  
Hayfa Jabnoun-Khiareddine ◽  
Bouzid Nasraoui ◽  
Mejda Daami-Remadi

Pythium ultimum is a common soilborne pathogen causing serious losses of pepper seedlings in nurseries and few weeks post-planting. Two pepper associated-P. ultimum isolates (P1 and P2) were shown pathogenic to pepper cv. Altar causing post-emergence damping-off with P2 isolate being the most aggressive. Fungal and bacterial antagonists have been evaluated in vitro and in vivo for their ability to suppress P. ultimum. In dual culture assay, Trichoderma harzianum, T. viride and Gliocladium virens inhibited pathogen radial growth by 18.54, 17.52 and 15.24%, respectively, relative to control, while none of the tested bacteria was shown able to significantly inhibit pathogen growth. However, drastic changes in pathogen hyphae expressed as strong lysis, the formation of mycelial cords and mycoparasitism have been observed. Pepper seeds treated with fungal antagonists’ conidial suspensions showed 60, 50 and 60% less pre-emergence damping-off infections, respectively, compared to the positive control. When tested as root dipping, only G. virens resulted in 40% reduced post-emergence damping-off. An improved seedlings fresh weight, by 79.31 and 76%, was respectively induced by G. virens-, and T. viride-based treatments while an increment of 27.58, 25.33 and 22.22 % was recorded following treatments with G. virens, T. viride and T. harzianum, relative to the positive control. The majority of tested bacterial isolates, applied as a seed treatment, had significantly improved the emergence percentage of inoculated seedlings as compared to control with Burkholderia glathei isolate 35 being the most efficient. When applied as root dipping, reduction of post-emergence damping-off ranged between 40 and 100% with Pseudomonas aureofaciens isolate 314 being the most effective agent. Seedlings treated with P. aureofaciens (314) and Bacillus pumilus (420) showed 35.38 and 28.51% higher heights, respectively. Plant weight was enhanced by 73.06, 61.18, 77.39, 61.8 and 67.93% over control following treatments with P. aureofaciens isolates 314 and 31, Bacillus pumilus 420, P. fluorescens and P. putida 227.


2019 ◽  
Vol 19 (1) ◽  
pp. 8
Author(s):  
Wagiyana Wagiyana ◽  
Didik Sulistyanto ◽  
Joko Waluyo

Entomopathogenic Nematodes (EpNs) that serve as biological control agents include Steinernema spp and  Heterorhabditis spp. EPNs Heterorhabditis indicus (Bromo Isolate) has a high toxicity against larvae Lepidoptera and Coleoptera and was successfully developed for mass production in Biological Control Laboratory of Jember University. These nematodes will be formulated as solid and liquid biopesticides. This research aims: to find EPNs local isolates from smallholder coffee plantations; to identify local and in vivo and in vitro cultured EPNs isolates; to determine the pathogenicity of EpNs local isolate against Coffee Berry Borrer (CBB) Hypothenemus hampei Ferr and to formulate EpNs in vitro culture as a liquid and solid formula. These formula were tested for the patogenicity and viability of EpNs to the larvae of H. hampei, Tenebrio molitor and Galleria melonella. The results showed that the pathogenecity of EpNs isolate to the larvae of CBB in Silo was 30% after 24 hours and 90% after 48 hours of in vivo inoculation. However, the mortality of CBB larvae was only 10% by liquid spraying on the coffee berry. The viability was 524 IJ (Infective Juvenile) on liquid formula packed on polyurethane sponge, and this was higher than that on solid formula (330 IJ).


Parasitology ◽  
1982 ◽  
Vol 84 (4) ◽  
pp. 177-204 ◽  
Author(s):  
J. J. Petersen

SUMMARYThis review highlights published research on the principal entomogenous nematodes that have potential as biological control agents of insects. The life-cycles and status of promising members of the families Allantonematidae, Diplogasteridae, Heterorhabditidae, Mermithidae, Neotylenchidae, Rhabditidae, Sphaerulariidae, Steinernematidae and Tetradonematidae are discussed. Emphasis is placed on attempts to control insect populations with these nematodes. Mass propagation of the Steinernematidae and Mermithidae are also discussed, including current in vivo and in vitro rearing systems. A number of these nematodes show promise as biological control agents but commercial development has been slow because of environmental limitations, host specificity and inherent problems associated with manipulation of living organisms. Although some of these nematodes have been considered for commercial preparation, it appears that they will remain ‘on the shelf’ until the need for such biological control provides small businesses with the incentive to make them available for general use.


2020 ◽  
Vol 55 (1) ◽  
pp. 27-34
Author(s):  
G. Zadehdabagh ◽  
K. Karimi ◽  
M. Rezabaigi ◽  
F. Ajamgard

The northern of Khuzestan province in Iran is mainly considered as one of the major areas of miniature rose production. Blossom blight caused by Botrytis cinerea has recently become a serious limiting factor in rose production in pre and post-harvest. In current study, an attempt was made to evaluate the inhibitory potential of some local Trichoderma spp. strains against B. cinerea under in vitro and in vivo conditions. The in vitro results showed that all Trichoderma spp. strains were significantly able to reduce the mycelial growth of the pathogen in dual culture, volatile and non-volatile compounds tests compared with control, with superiority of T. atroviride Tsafi than others. Under in vivo condition, the selected strain of T. atroviride Tsafi had much better performance than T. harzianum IRAN 523C in reduction of disease severity compared with the untreated control. Overall, the findings of this study showed that the application of Trichoderma-based biocontrol agents such as T. atroviride Tsafi can be effective to protect cut rose flowers against blossom blight.


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