| 1. |
- Attitalla, Idress Hamad, et al.
(författare)
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A rapid molecular method for differentiating two special forms (lycopersici and radicis-lycopersici) of Fusarium oxysporum
- 2004
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Ingår i: Mycological Research. - 0953-7562 .- 1469-8102. ; 108:7, s. 787-794
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Tidskriftsartikel (refereegranskat)abstract
- Two pathogenic special forms (f. sp.) of the Fusarium oxysporum species complex f. sp. lycopersici (Fol) and f. sp. radicis-lycopersici (Forl) are morphologically indistinguishable. Although they are pathogenic to the same host genus Lycopersicon (tomato), and infect the same tomato cultivar, they form distinct diseases; Fol causes wilt and Forl causes crown rot and root rot. These two special forms apparently exist as genetically isolated populations, based on vegetative compatibility and molecular variation at the DNA level. In seeking efficient diagnostic tools for differentiating Fol and Forl isolates, we examined three techniques: isozyme analysis, mitochondrial DNA (mtDNA) RFLP by HaeIII-digestion of total genomic DNA, and an osmotic method using high performance liquid chromatography (HPLC) to detect fungal pigments. The isolates were collected from geographically widespread locations. Distinct HPLC-profile differences were found between an endophytic non-pathogenic isolate and the other pathogenic isolates. However, the direct mtDNA RFLP technique proved to be an efficient diagnostic tool for routine differentiation of Fol and Forl isolates.
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| 2. |
- Johnsson, Anna-Ida, et al.
(författare)
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Development and evaluation of SCAR markers for a Pseudomonas brassicacearum strain used in biological control of snow mould
- 2009
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Ingår i: Biological Control. - : Elsevier BV. - 1049-9644 .- 1090-2112. ; 48, s. 181-187
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Tidskriftsartikel (refereegranskat)abstract
- Biological control microorganisms have long been promoted as an alternative to conventional pesticides. Before registration of a microbial biocontrol product for commercial sale, it must be evaluated as regards potential spread and persistence after release. In this study, strainspecific sequence-characterized amplified region (SCAR) markers were developed to monitor the biocontrol candidate strain Pseudomonas brassicacearum MA250, which is effective against snow mould (Microdochium nivale). One SCAR marker, OPA2-73, was used in quantitative real-time PCR (Q-PCR) on samples from a climate chamber experiment in which winter wheat seeds were treated with the bacterium or a chemical control agent, or left untreated. The results showed that MA250 persisted for up to 3 weeks after sowing on the kernel residues and also colonized the roots of treated seedlings. Total MA250 cell numbers on biocontrol treated seedlings after three weeks were approximately 10(6) Cells, compared with the original inoculum of 10(6)-10(7) cells per seed. Corresponding cell numbers of MA250 on chemically treated and untreated seedlings were below the detection limit. This study shows that SCAR marker OPA2-73 is a specific and sensitive tool for monitoring the biocontrol microorganism MA250 in environmental samples. (C) 2008 Elsevier Inc. All rights reserved.
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| 3. |
- Johnsson, Anna-Ida, et al.
(författare)
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Fate and behaviour of a seed-applied Pseudomonas brassicacearum strain in a winter wheat field trial, as determined by analysis with SCAR markers
- 2012
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Ingår i: Biocontrol Science and Technology. - : Informa UK Limited. - 0958-3157 .- 1360-0478. ; 22, s. 379-392
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Tidskriftsartikel (refereegranskat)abstract
- The fate and behaviour of the seed-applied biocontrol strain Pseudomonas brassicacearum MA250 in a field trial with winter wheat was determined using sequence-characterised amplified region (SCAR) markers. Samples of below-ground plant parts from healthy and withered (due to snow mould infection) seedlings were collected approximately one and seven months after sowing, which was performed in early autumn. DNA was extracted from roots and remaining parts of seeds with adhering soil, and the abundance of the strain was determined in quantitative real-time PCR (qPCR) assays. The results show that the introduced strain persisted over the whole trial-period of seven months. On termination of the trial (after seven months) the below-ground plant parts of each plant housed 10(6)-10(7) cells, substantially less than the original approximately 10 9 cells inoculated onto the seed. In healthy seedlings, there was a shift in cell numbers from seeds to roots between the samplings, suggesting colonisation of the roots during this time. The results show that with sufficient attention given to analytical control measures and the possibility of resident background populations, SCAR markers in combination with qPCR provide valuable information regarding the fate and behaviour of biocontrol micro-organisms under field conditions.
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