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Daranas N, Badosa E, Montesinos E, Bonaterra A. Colonization and population dynamics of total, viable, and culturable cells of two biological control strains applied to apricot, peach, and grapevine crops. Front Microbiol 2024; 14:1324965. [PMID: 38249452 PMCID: PMC10797078 DOI: 10.3389/fmicb.2023.1324965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 12/07/2023] [Indexed: 01/23/2024] Open
Abstract
The ecological fitness of the biological control strains Bacillus velezensis A17 and Lactiplantibacillus plantarum PM411 was evaluated in different crops, geographical zones, and growing seasons. Both strains (2 g L-1 of dried formulation) were spray-inoculated on apricot trees, peach trees, and grapevines. Depending on the crop, flowers, fruits, and leaves were picked at several sampling time points. The population dynamics of viable, viable but non-culturable, and dead cells were studied by comparing viability qPCR (v-qPCR), qPCR, and plate counting estimations. A17 showed high survival rates in apricot, peach, and grapevine organs. The A17 viability was confirmed since qPCR and v-qPCR estimations did not significantly differ and were rather constant after field applications. However, higher population levels were estimated by plate counting due to the non-selective characteristics of the medium used. The viability of PM411 was constrained by plant organ, crop, and climate conditions, being higher in apricot than in grapevine. PM411 survival declined after field application, indicating difficulties in its establishment. The PM411 population level was made up of dead, culturable, and viable but non-culturable cells since significant differences between the three methods were observed. In conclusion, A17 and PM411 differ strongly in their survival in grapevine, peach, and apricot.
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Affiliation(s)
| | | | | | - Anna Bonaterra
- Institute of Food and Agricultural Technology-CIDSAV, University of Girona, Girona, Spain
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Tut G, Magan N, Brain P, Xu X. Molecular Assay Development to Monitor the Kinetics of Viable Populations of Two Biocontrol Agents, Bacillus subtilis QST 713 and Gliocladium catenulatum J1446, in the Phyllosphere of Lettuce Leaves. BIOLOGY 2021; 10:biology10030224. [PMID: 33804029 PMCID: PMC8001495 DOI: 10.3390/biology10030224] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 03/08/2021] [Accepted: 03/10/2021] [Indexed: 11/19/2022]
Abstract
Simple Summary There is a need to be able to track the viable populations of biocontrol agents when applied on the foliar surfaces of plants. We have developed a molecular-based method for the quantification of viable cells of two commercial biocontrol agents—a bacterium (Bacillus subtilis) and a fungus (Gliocladium catenulatum). The method has been tested on the leaf surfaces of lettuce plants to examine the changes in viable population over 10–12 days for the first time. Abstract Optimising the use of biocontrol agents (BCAs) requires the temporal tracking of viable populations in the crop phyllosphere to ensure that effective control can be achieved. No sensitive systems for quantifying viable populations of commercially available BCAs, such as Bacillus subtilis and Gliocladium catenulatum, in the phyllosphere of crop plants are available. The objective of this study was to develop a method to quantify viable populations of these two BCAs in the crop phyllosphere. A molecular tool based on propidium monoazide (PMA) (PMAxx™-qPCR) capable of quantifying viable populations of these two BCAs was developed. Samples were treated with PMAxx™ (12.5–100 μM), followed by 15 min incubation, exposure to a 800 W halogen light for 30 min, DNA extraction, and quantification using qPCR. This provided a platform for using the PMAxx™-qPCR technique for both BCAs to differentiate viable from dead cells. The maximum number of dead cells blocked, based on the DNA, was 3.44 log10 for B. subtilis and 5.75 log10 for G. catenulatum. Validation studies showed that this allowed accurate quantification of viable cells. This method provided effective quantification of the temporal changes in viable populations of the BCAs in commercial formulations on lettuce leaves in polytunnel and glasshouse production systems.
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Affiliation(s)
- Gurkan Tut
- NIAB East Malling Research, West Malling, Kent ME19 6BJ, UK; (G.T.); (P.B.); (X.X.)
- Applied Mycology Group, Environment and AgriFood Theme, Cranfield University, Cranfield, Bedford MK43 0AL, UK
| | - Naresh Magan
- Applied Mycology Group, Environment and AgriFood Theme, Cranfield University, Cranfield, Bedford MK43 0AL, UK
- Correspondence:
| | - Philip Brain
- NIAB East Malling Research, West Malling, Kent ME19 6BJ, UK; (G.T.); (P.B.); (X.X.)
| | - Xiangming Xu
- NIAB East Malling Research, West Malling, Kent ME19 6BJ, UK; (G.T.); (P.B.); (X.X.)
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Miotto M, Barretta C, Ossai SO, da Silva HS, Kist A, Vieira CRW, Parveen S. Optimization of a propidium monoazide-qPCR method for Escherichia coli quantification in raw seafood. Int J Food Microbiol 2020; 318:108467. [PMID: 31835094 DOI: 10.1016/j.ijfoodmicro.2019.108467] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 11/13/2019] [Accepted: 11/30/2019] [Indexed: 11/15/2022]
Abstract
The present study compared different concentrations of propidium monoazide (PMA), time of exposure to light and different light intensities to determine the optimal conditions for the quantification of viable Escherichia coli in cell suspension and in food matrix. The influence of cell density and the effectiveness of PMA in viable but non-culturable (VBNC) E. coli cells were evaluated and also applied in food matrix. For that purpose, different concentrations of PMA (20 μM, 40 μM, 50 μM, 60 μM and 80 μM) under different times of exposure (5 min, 10 min, 15 min, 20 min and 30 min) to lights of different intensities (500 W and 650 W) were evaluated. After determining the optimal conditions, the PMA-qPCR methods were applied to different compositions of live and heat-killed E. coli suspensions (v:v; 0:1; 1:0; 1:1) in concentrations ranging from 3 Log to 7 Log CFU/mL. The same dilutions were prepared with E. coli in VBNC state and applied in food matrix. The results obtained from qPCR, PMA-qPCR and plate counts were compared. The results suggested that a PMA treatment of 50 μM PMA for 15 min under 650 W light intensity was optimal under our conditions. For E. coli cell suspensions, the amplification of heat-killed cells was inhibited greatly by PMA when concentrations were ≤ 5 Log CFU/mL. For the samples of oyster inoculated with heat-killed cells, E. coli was not detected by PMA-qPCR in concentrations ≤4 Log CFU/g. Regarding the results with VBNC state, we considered the PMA-qPCR method to be applicable for enumerating E. coli VBNC cells in oyster samples. Based on our findings, we further recommend the use of PMA-qPCR with the aim of reducing the amplification of dead cells for improving its performance, since false-positives could still occur depending on the level of E. coli in the sample. The application of the PMA-qPCR for quantification of bacteria, compared to the use of culture-dependent methods, is quite promising. However, further studies are recommended, especially using different food matrices.
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Affiliation(s)
- Marilia Miotto
- Department of Food Science and Technology, Federal University of Santa Catarina, 1346 Admar Gonzaga, 88034-001 Florianopolis, Santa Catarina, Brazil.
| | - Clarissa Barretta
- Department of Food Science and Technology, Federal University of Santa Catarina, 1346 Admar Gonzaga, 88034-001 Florianopolis, Santa Catarina, Brazil
| | - Sylvia O Ossai
- Food Science and Technology Program, University of Maryland Eastern Shore, 2116 Backbone Road, 21853 Princess Anne, MD, United States
| | - Helen Silvestre da Silva
- Department of Food Science and Technology, Federal University of Santa Catarina, 1346 Admar Gonzaga, 88034-001 Florianopolis, Santa Catarina, Brazil
| | - Airton Kist
- Laboratory of Computational and Applied Statistics, Department of Mathematics and Statistics, State University of Ponta Grossa, 4748 Gen. Carlos Cavalcanti, 84030-900 Ponta Grossa, Parana, Brazil
| | - Cleide Rosana Werneck Vieira
- Department of Food Science and Technology, Federal University of Santa Catarina, 1346 Admar Gonzaga, 88034-001 Florianopolis, Santa Catarina, Brazil
| | - Salina Parveen
- Food Science and Technology Program, University of Maryland Eastern Shore, 2116 Backbone Road, 21853 Princess Anne, MD, United States
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Cattò C, Cappitelli F. Testing Anti-Biofilm Polymeric Surfaces: Where to Start? Int J Mol Sci 2019; 20:E3794. [PMID: 31382580 PMCID: PMC6696330 DOI: 10.3390/ijms20153794] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 08/02/2019] [Indexed: 12/11/2022] Open
Abstract
Present day awareness of biofilm colonization on polymeric surfaces has prompted the scientific community to develop an ever-increasing number of new materials with anti-biofilm features. However, compared to the large amount of work put into discovering potent biofilm inhibitors, only a small number of papers deal with their validation, a critical step in the translation of research into practical applications. This is due to the lack of standardized testing methods and/or of well-controlled in vivo studies that show biofilm prevention on polymeric surfaces; furthermore, there has been little correlation with the reduced incidence of material deterioration. Here an overview of the most common methods for studying biofilms and for testing the anti-biofilm properties of new surfaces is provided.
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Affiliation(s)
- Cristina Cattò
- Department of Food Environmental and Nutritional Sciences, Università degli Studi di Milano, via Celoria 2, 20133 Milano, Italy
| | - Francesca Cappitelli
- Department of Food Environmental and Nutritional Sciences, Università degli Studi di Milano, via Celoria 2, 20133 Milano, Italy.
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Nurliyana MR, Sahdan M, Wibowo K, Muslihati A, Saim H, Ahmad S, Sari Y, Mansor Z. The Detection Method ofEscherichia coliin Water Resources: A Review. ACTA ACUST UNITED AC 2018. [DOI: 10.1088/1742-6596/995/1/012065] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Martini M, Moruzzi S, Ermacora P, Loi N, Firrao G. Quantitative real-time PCR and high-resolution melting (HRM) analysis for strain-specific monitoring of fluorescent pseudomonads used as biocontrol agents against soil-borne pathogens of food crops. Trends Food Sci Technol 2015. [DOI: 10.1016/j.tifs.2015.10.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Xiao L, Zhang Z, Sun X, Pan Y, Zhao Y. Development of a quantitative real-time PCR assay for viable Salmonella spp. without enrichment. Food Control 2015. [DOI: 10.1016/j.foodcont.2015.03.050] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Soto-Muñoz L, Torres R, Usall J, Viñas I, Solsona C, Teixidó N. DNA-based methodologies for the quantification of live and dead cells in formulated biocontrol products based on Pantoea agglomerans CPA-2. Int J Food Microbiol 2015; 210:79-83. [PMID: 26114590 DOI: 10.1016/j.ijfoodmicro.2015.06.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Revised: 06/02/2015] [Accepted: 06/17/2015] [Indexed: 10/23/2022]
Abstract
Pantoea agglomerans strain CPA-2 is an effective biocontrol agent (BCA) against the major postharvest pathogens present on pome and citrus fruits. Dehydration, such as freeze-drying, spray-drying and fluidized bed drying is one of the best ways to formulate BCAs. In this work, the survival of CPA-2 cells after formulation was determined by dilution plating and molecular methods as qPCR alone and combined with a sample pretreatment with a propidium monoazide dye (PMA-qPCR) and they were used to calculate treatment concentrations in efficacy trials on postharvest oranges. Furthermore, no significant differences in CPA-2 survival were observed as determined by dilution plating and PMA-qPCR after both the freeze drying and fluidized bed drying processes; however, an interesting significant difference was observed in the spray dried product comparing all quantitative methods. A difference of 0.48 and 2.17 log10 CFU or cells g/dw was observed among PMA-qPCR with qPCR and dilution plating, respectively. According to our study, dilution plating was shown to be an unreliable tool for monitoring the survival of CPA-2 after spray drying. In contrast, the combination of PMA and qPCR enabled a quick and unequivocal methodology to enumerate viable and VBNC CPA-2 cells under stress-dried conditions. Efficacy trials showed that, after 3 days, spray drying formulation rehydrated with 10% non-fat skimmed milk (NFSM) was as effective as fresh cells to control Penicillium digitatum in oranges.
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Affiliation(s)
- Lourdes Soto-Muñoz
- Food Technology Department, Lleida University, XaRTA-Postharvest, Agrotecnio Center, Av. Rovira Roure, 191, 25198 Lleida, Catalonia, Spain
| | - Rosario Torres
- IRTA, XaRTA-Postharvest, Edifici Fruitcentre, Parc Científic i Tecnològic Agroalimentari de Lleida, Parc de Gardeny, 25003 Lleida, Catalonia, Spain
| | - Josep Usall
- IRTA, XaRTA-Postharvest, Edifici Fruitcentre, Parc Científic i Tecnològic Agroalimentari de Lleida, Parc de Gardeny, 25003 Lleida, Catalonia, Spain
| | - Inmaculada Viñas
- Food Technology Department, Lleida University, XaRTA-Postharvest, Agrotecnio Center, Av. Rovira Roure, 191, 25198 Lleida, Catalonia, Spain
| | - Cristina Solsona
- IRTA, XaRTA-Postharvest, Edifici Fruitcentre, Parc Científic i Tecnològic Agroalimentari de Lleida, Parc de Gardeny, 25003 Lleida, Catalonia, Spain
| | - Neus Teixidó
- IRTA, XaRTA-Postharvest, Edifici Fruitcentre, Parc Científic i Tecnològic Agroalimentari de Lleida, Parc de Gardeny, 25003 Lleida, Catalonia, Spain.
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