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| 2. |
- Schmitt, A., et al.
(författare)
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Evaluation of non-chemical seed treatment methods for the control of Phoma valerianellae on lamb’s lettuce seeds
- 2009
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Ingår i: Journal of Plant Diseases and Protection. - 1861-3829. ; 116:5, s. 200-207
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the present study was to identify seed treatment methods for eradicating Phoma valerianellae from lamb’s lettuce seeds in organic vegetable production. Using seeds naturally infested with the pathogen, the effect of three physical methods (hot water, aerated steam, electron treatment) and different agents of natural origin (micro-organisms, plant derived products, resistance inducers) was tested on moist filter paper, in seed trays under controlled conditions and in the field. in an initial screening, none of the tested putative resistance inducers prevented infection by P. valerianellae, while two out of seven formulated micro-organism preparations and six out of 16 experimental microbial strains were effective. When selected agents and the three physical seed treatment methods were compared in blotter and seed tray tests, the physical methods were generally the most effective treatments, while the micro-organism treatments were clearly less efficacious. However, in field experiments with the same seed lots and the same treatments, a statistically significant increase in plant stand was not obtained with any of the treatments. Combinations of the three physical treatment methods with selected non-chemical agents did not perform better than the physical treatments alone. The most effective alternative seed treatments identified in the present study, aerated steam, hot water, electron treatment and thyme oil (0.1%), can be recommended for eradication of P. valerianellae from lamb’s lettuce seeds in organic farming. Because their efficacy was generally as high as that of the chemical fungicide Aatiram (active ingredient thiram), they are also potentially suited for use in conventional vegetable production.
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| 5. |
- Jandrić, Petar, et al.
(författare)
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Teaching in the Age of Covid-19—1 Year Later
- 2021
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Ingår i: Postdigital Science and Education. - : Springer. - 2524-485X .- 2524-4868. ; 3:3, s. 1073-1223
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Tidskriftsartikel (refereegranskat)
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| 8. |
- Oksinska, M. P., et al.
(författare)
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Resistance to oxidation products of caffeic acid is important for efficient colonization of wheat seedlings by Pseudomonas proteolytica strain PSR114
- 2013
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Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 66, s. 71-80
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Tidskriftsartikel (refereegranskat)abstract
- The interrelationships between plants and rhizosphere bacteria are strongly dependent on the quality and quantity of root exudates. The ability to colonize roots is crucial for pseudomonads to function as biological control agents of root- and soil-borne pathogenic microbes. The multiplication of rhizosphere bacteria is restricted in the presence of simple phenolic compounds, which are components of the resistance mechanisms of plants to pathogens. Caffeic acid is a phenolic compound, which is commonly found in wheat tissues. It is prone to oxidation into o-quinones, which are toxic to microorganisms. The aim of the present study was to determine whether the ability of microorganisms to resist caffeic acid and its oxidation products could play a role in the early colonization of wheat seedlings. Among the fluorescent pseudomonads that we have studied, strain PSR114 is one of the most efficient colonizers of wheat seedlings during the first 48 h after seed germination, and it is particularly resistant to products resulting from the spontaneous oxidation of caffeic acid. This strain was isolated from the rhizosphere of oilseed rape and identified as being closely related to Pseudomonas proteolytica through the analysis of 16S rRNA and rpoB gene sequences. At pH 7.0, this strain grew intensively in the presence of 1.50 mg mL−1 of caffeic acid. Its multiplication was partially reduced in the presence of oxidized caffeic acid at concentrations above 0.21 mg mL−1, and completely inhibited at concentrations above 0.38 mg mL−1. A Tn5 transposon mutant of PSR114 had lower level of resistance to the oxidation products of caffeic acid, as well as reduced capacity to colonize wheat seedlings when compared to the wild type strain. This work demonstrates that resistance to oxidation products of caffeic acid can be important for successful bacterial colonization of wheat seedlings.
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| 9. |
- Pinedo, Cristina, et al.
(författare)
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Isotopic Labeling Studies Reveal the Patulin Detoxification Pathway by the Biocontrol Yeast Rhodotorula kratochvilovae LS11
- 2018
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Ingår i: Journal of Natural Products. - : American Chemical Society (ACS). - 0163-3864 .- 1520-6025. ; 81:12, s. 2692-2699
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Tidskriftsartikel (refereegranskat)abstract
- Patulin (1) is a mycotoxin contaminant in fruit and vegetable products worldwide. Biocontrol agents, such as the yeast Rhodotorula kratochvilovae strain LS11, can reduce patulin (1) contamination in food. R. kratochvilovae LS11 converts patulin (1) into desoxypatulinic acid (DPA) (5), which is less cytotoxic than the mycotoxin (1) to in vitro human lymphocytes. In the present study, we report our investigations into the pathway of degradation of patulin (1) to DPA (5) by R. kratochvilovae. Isotopic labeling experiments revealed that 5 derives from patulin (1) through the hydrolysis of the γ-lactone ring and subsequent enzymatic modifications. The ability of patulin (1) and DPA (5) to cause genetic damage was also investigated by the cytokinesis-block micronucleus cytome assay on in vitro human lymphocytes. Patulin (1) was demonstrated to cause much higher chromosomal damage than DPA (5).
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