scholarly journals Response of Soil Microbiome Structure to Biological Control Agents (BCAs) in Strawberry Greenhouse

2020 ◽  
Author(s):  
Senlin Liu ◽  
Muzammil Hassan Khan ◽  
Zhongyuan Yuan ◽  
Sarfraz Hussain ◽  
Hui Cao ◽  
...  
Keyword(s):  
Biological Control ◽  
Microbial Community ◽  
Fungal Pathogens ◽  
Soil Health ◽  
Amplicon Sequencing ◽  
Soil Microbiome ◽  
Continuous Cropping ◽  
Biological Control Agents ◽  
Land Utilization ◽  
Effective Microorganisms

AbstractContinuous cropping always leads to severe abiotic and biotic problems, especially the high-intensity land utilization in greenhouses, which causes widespread concern. Effective Microorganisms (EM) and Bacillus subtilis (BS) have been widely used to promote plant growth and increase yields as biological control agents (BCAs). However, their effects on soil microbes are obscure. To regulate the microbial community in continuous cropping strawberry soils, we developed four soil amendments by combining EM and BS with compost. The amplicon sequencing of bacterial and fungal ribosomal markers was applied to study the response of the soil microbiome structure. We noticed a sharp increase in bacterial diversity after the addition of EM-treated high compost and BS-treated low compost, while there was no significant change in fungal diversity among treatments. Interestingly, both the relative abundance and FUNGuild predictions was consistent in revealing that BCAs may inhibit fungal pathogens in soils. Correlation analysis indicated that soil microbial community was indirectly driven by soil properties. Co-occurrence networks demonstrated that BCAs could be microecologically homogeneous through enhancing bacterial network complexity and modularity. Collectively, EM-treated high compost and BS-treated low compost can well regulate the microbial community structure and thus maintain soil health.

scholarly journals Response of soil microbiome structure and its network profiles to four soil amendments in monocropping strawberry greenhouse

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0245180
Author(s):  
Senlin Liu ◽  
Muzammil Hassan Khan ◽  
Zhongyuan Yuan ◽  
Sarfraz Hussain ◽  
Hui Cao ◽  
...  
Keyword(s):  
Microbial Community ◽  
Plant Pathogens ◽  
Soil Amendments ◽  
Amplicon Sequencing ◽  
Growth And Yield ◽  
Yield Enhancement ◽  
Soil Microbiome ◽  
Continuous Cropping ◽  
Effective Microorganisms ◽  
Fungal Plant Pathogens

With the constant surge of strawberry cultivation and human demand, widespread concern has been expressed about the severe soil and plant health problems caused by continuous strawberry cropping, particularly monocropping in greenhouses. Effective microorganisms (EM) and Bacillus subtilis (BS) have been extensively commercialized as biological control agents (BCAs) to promote plant growth and yield enhancement. However, their effects on soil microbes are obscure. To regulate the microbial community in continuous cropping strawberry soils, we developed four soil amendments based on these two BCAs by adding low and high contents of compost. The amplicon sequencing of bacterial and fungal ribosomal markers was applied to study the response of the soil microbiome structure. We noticed a sharp increase in bacterial diversity after adding EM-treated high compost and BS-treated low compost, while there was no significant change in fungal diversity among treatments. Through taxonomic classification and FUNGuild analysis, we found that the application of soil amendments resulted in a significant decline in the relative abundance of fungal plant pathogens (Rhizopus, Penicillium and Fusarium) in the soils; accordingly, the metabolic functions of a range of detrimental fungi were inhibited. Correlation analysis indicated that soil microbial community was indirectly driven by soil physicochemical properties. Co-occurrence networks revealed that soil amendments contributed to the connectivity of bacterial network, and EM-treated with high compost was the most complex and balanced. Collectively, EM-treated high compost and BS-treated low compost can well regulate the microbial community structure and thus maintain soil health.

Evaluation of Fungal Pathogens as Biological Control Agents for Cogongrass (Imperata cylindrica)1

2005 ◽  
Vol 19 (1) ◽  
pp. 19-26 ◽  
Author(s):  
CAMILLA B. YANDOC ◽  
RAGHAVAN CHARUDATTAN ◽  
DONN G. SHILLING
Keyword(s):  
Biological Control ◽  
Fungal Pathogens ◽  
Imperata Cylindrica ◽  
Biological Control Agents

Differential Susceptibility of Bagrada hilaris (Hemiptera: Pentatomidae) to Different Species of Fungal Pathogens

2019 ◽  
Author(s):  
Anahi A Barrera-López ◽  
Ariel W Guzmán-Franco ◽  
Materesa Santillán-Galicia ◽  
Fernando Tamayo-Mejía ◽  
Rafael Bujanos-Muñiz ◽  
...  
Keyword(s):  
Biological Control ◽  
Fungal Pathogens ◽  
Microbial Control ◽  
Differential Susceptibility ◽  
Field Studies ◽  
The United States ◽  
Fungal Species ◽  
Biological Control Agents ◽  
Percent Mortality ◽  
Microbial Agents

Abstract Bagrada hilaris Burmeister (Hemiptera: Pentatomidae) is a pest of Palearctic origin. Its presence in the United States was first reported in 2008 and in Mexico in 2014; it affects brassica crops. There are practically no reports of natural enemies of B. hilaris in America. Entomopathogenic fungi are strong candidates for microbial control of this pest. Evaluating the susceptibility of this pest to fungi that are native to the region where they will be used is a sensible first step to finding candidate biological control agents. The aim of our research was to select potential microbial agents to control B. hilaris. Eleven isolates of Beauveria bassiana, Beauveria pseudobassiana, Metarhizium anisopliae, and Isaria fumosorosea were evaluated to determine the susceptibility of B. hilaris. Isolates of B. bassiana caused the highest mortality due to infection (100%) compared with the other isolates. The I. fumosorosea isolate caused the lowest percent mortality (56%). The two B. bassiana isolates Bb88 and AP3 were more virulent than M. anisopliae isolate Ma129. The sex of the insect had no effect on infection levels achieved by B. bassiana isolates Bb88 and AP3. The results of our study contribute valuable information for the development of fungal species with potential to manage B. hilaris populations. Field studies are the next step in order to develop these isolates as biological control agents of B. hilaris.

Fungi as biological control agents of arthropods of agricultural and medical importance

Parasitology ◽  
1982 ◽  
Vol 84 (4) ◽  
pp. 205-240 ◽  
Author(s):  
R. A. Hall ◽  
B. Papierok
Keyword(s):  
Biological Control ◽  
Fungal Pathogens ◽  
Abiotic Factors ◽  
Organic Pollution ◽  
Verticillium Lecanii ◽  
Physical Factors ◽  
Biological Control Agents ◽  
Yield Data ◽  
Medical Importance ◽  
Terrestrial Insects

SUMMARYThere are many species of fungi attacking terrestrial and aquatic insects of agricultural and medical importance. Of these, few species have received much attention with a view to their use as biological control agents. The mechanisms of infection have been comparatively well studied, although many questions remain to be answered. The knowledge so far obtained has shed some light on the reasons for host specificity. Temperature, above all relative humidity, and their interactions are the most important physical factors influencing infection of terrestrial insects by entomopathogenic fungi and these are discussed in relation to epizootiological events. In aquatic environments, temperature, salinity and organic pollution are the important factors. In addition to these physical factors, numerous biotic factors at the level of the insect and the fungal pathogen influence both infection and spread of disease in insect populations. The complexity of the interactions of the biotic and abiotic factors makes it extremely difficult to study the influence of any one of these. Virulence of fungal pathogens and its measurement are discussed, together with the shortcomings of present bioassay systems; virtually no laboratory bioassay system exists which has been designed to yield data meaningful in the field. Mass-production techniques are described as are their inherent problems and those of formulation and storage. Finally, the achievements of fungal control of insects in the field are reviewed. Thus far, several species are mass-produced and are in widespread use, two of which,Verticillium lecaniiandHirsutella thompsonii, have been commercialized. More studies, ecological, fundamental and developmental are required in this field to realize fully the potential of other candidate fungi.

scholarly journals In vitro evaluation of grapevine endophytes, epiphytes and sap micro-organisms for potential use to control grapevine trunk disease pathogens

2021 ◽  
Author(s):  
Robert Blundell ◽  
Molly Arreguin ◽  
Akif Eskalen
Keyword(s):  
Biological Control ◽  
Mycelial Growth ◽  
Fungal Pathogens ◽  
Dual Culture ◽  
Biological Control Agents ◽  
In Planta ◽  
Eutypa Dieback ◽  
Fungal Isolates ◽  
Wound Protection

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.

scholarly journals Potential Biological Control Agents for Soilborne Fungal Pathogens in Tennessee Snap Bean Farms

HortScience ◽  
2020 ◽  
Vol 55 (7) ◽  
pp. 988-994
Author(s):  
Jacqueline Joshua ◽  
Margaret T. Mmbaga
Keyword(s):  
Biological Control ◽  
Fungal Pathogens ◽  
In Vivo Studies ◽  
Growth Media ◽  
Bacterial Cells ◽  
Biological Control Agents ◽  
Snap Bean ◽  
Inhibition Zones

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.

scholarly journals Evaluation of Fungal Pathogens as Biological Control Agents for the Paddy Weed, Echinochloa Species by Drop Inoculation.

1997 ◽  
Vol 63 (5) ◽  
pp. 366-372 ◽  
Author(s):  
Hiroshi TSUKAMOTO ◽  
Masatoshi GOHBARA ◽  
Mitsuya TSUDA ◽  
Takane FUJIMORI
Keyword(s):  
Biological Control ◽  
Fungal Pathogens ◽  
Biological Control Agents

scholarly journals Effect of Fungicide Application on Lowbush Blueberries Soil Microbiome

2021 ◽  
Vol 9 (7) ◽  
pp. 1366
Author(s):  
Austin W. Lloyd ◽  
David Percival ◽  
Svetlana N. Yurgel
Keyword(s):  
Microbial Communities ◽  
Combined Treatment ◽  
Soil Health ◽  
Cropping System ◽  
Soil Nutrient ◽  
Amplicon Sequencing ◽  
Soil Microbiome ◽  
Nutrient Cycles ◽  
Eastern Canada ◽  
The Impact

Lowbush blueberries (Vaccinium sp.) are perennial crops produced throughout eastern Canada and Maine through management of wild populations. Given the constraints of this cropping system, the application of fungicides is critical to reducing disease pressure and ensuring consistent yields. However, as plant health is intertwined with soil health, it is important to consider the impact of fungicides on microbial communities. To understand the effects of fungicides in this context, bacterial and fungal microbial communities from fungicide-treated plots, as well as untreated control plots (UTG) were analyzed using amplicon sequencing. The fungicides, considered collectively as a combined treatment group (CTG), lead to a loss in fungal richness. One family, Clavariaceae, had an increased abundance under prothioconazole relative to UTG. This finding may be significant as taxa in Clavariaceae have been thought to potentially form ericoid mycorrhizae with Vaccinium. Five functional pathways and 74 enzymes differed significantly in relative abundance between CTG and UTG including enzymes associated with soil nutrient cycles. Most notably, enzymes corresponding to the breakdown of halogen-organic compounds had an increased abundance in CTG, suggesting bacterial fungicide degradation. Some enzymes associated with soil nutrient cycles differed significantly, possibly implying changes to nutrient pathways due to fungicide treatment.

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