Journal: Chemical and Biological Technologies in Agriculture

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Springer

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2196-5641

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2016 - 20193
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Publications 1 - 3 of 3
  • Direct identification of Monilinia brown rot fungi on infected fruits by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry
    Item type: Journal Article
    Freimoser, Florian M.; Hilber-Bodmer, Maja; Brunisholz, René; et al. (2016)
    Chemical and Biological Technologies in Agriculture
    Background Brown rot of stone and pome fruit is a serious fungal disease that is mainly caused by four species in the genus Monilinia. Of these four species, Monilinia fructicola is the most devastating pathogen and of particular concern because it undergoes sexual recombination and has recently been introduced to Europe. So far, Monilinia diagnosis required a multiplex PCR analysis and gel electrophoresis. In contrast, intact-protein biotyping by mass spectrometry is considerably faster and cheaper. However, it usually requires an in vitro cultivation step prior to the MALDI analysis. It was thus attempted to establish a method for the identification of Monilinia species by MALDI biotyping with fungal material derived directly from infected fruits; without an in vitro cultivation step. Results To simplify and render MALDI biotyping of fungi more reliable, an improved protocol for the preparation of crude protein extracts and for collecting MALDI-TOF MS data for biotyping was developed. We generated reference spectra for all four Monilinia brown rot fungi and were able to reliably identify Monilinia species based on fungal material that was collected directly from infected fruits. This method allowed the correct, fast and economic identification of M. fructicola and M. laxa, while M. fructigena and M. polystroma could not be distinguished reliably. Conclusions MALDI biotyping may be used as an economical tool for the routine diagnosis of Monilinia brown rot fungi on infected fruits.
  • Application of MALDI-TOF mass spectrometry and specific PCR for tracking of E. coli O157:Hˉ strain 431/97 in Batavia lettuce
    Item type: Journal Article
    Weiss, Agnes; Heinold, Susanne; Brunisholz, René; et al. (2019)
    Chemical and Biological Technologies in Agriculture
    Background In this study, lettuce roots and leaves were contaminated with enterohemorrhagic Escherichia coli O157:H− strain 431/97 under greenhouse conditions. Furthermore, the internalization of strain 431/97 in lettuce roots and leaves was examined. To track the inoculated bacteria during the experiments and to differentiate them from the autochthonous microbiota, a combined protocol including matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) and PCR was established. Results At different time points after inoculation of Batavia lettuce with 5.5 × 106 cfu/mL (high inoculation level) or 3.0 × 101 cfu/mL (low inoculation level) E. coli O157:H− strain 431/97 as well as sterile 0.9% (w/v) sodium chloride solution (negative control), samples from the root and the leaf were taken and surface disinfected with gentamicin. After homogenization, microorganisms were isolated from the samples and analyzed by MALDI-TOF MS. Analysis of the root samples resulted in bacterial counts of 1.0 × 102–1.0 × 106 cfu/0.25 g depending on the inoculated viable counts and the incubation period. In the leaf samples, strain 431/97 was not detected. The investigation of the viable cell counts of E. coli O157:H− 431/97 following irrigation of the leaves resulted in bacterial counts of 102 cfu/0.25 g for the disinfected leaf samples. Conclusions Thus, the established protocol is suitable for detecting the investigated strain under greenhouse conditions in plant infection experiments. This strain may indeed survive in the soil, but did not enter the plant via the root in detectable numbers. Contrarily, viable counts exceeding the generally accepted infective dose of less than 100 cells for enterohemorrhagic E. coli were determined internalized after irrigation of the leaves. As this may pose a risk for the consumer, the present study provides a valuable set of tools for further research.
  • Nano- and Pheroid technologies for development of foliar iron fertilizers and iron biofortification of soybean grown in South Africa
    Item type: Journal Article
    Knijnenburg, Jesper T.N.; Hilty, Florentine M.; Oelofse, Janro; et al. (2018)
    Chemical and Biological Technologies in Agriculture
    Background Foliar iron (Fe) fertilization of crops may increase Fe concentrations in edible portions of plants and improve yield in soils with low available Fe. However, the role of foliar Fe fertilization in increasing seed Fe has not been studied in soybeans (Glycine max). In this study, the Pheroid® nutrient delivery technology was combined with FeSO4 or nanostructured FePO4 to develop potential new Fe foliar fertilizers. Eight different treatments including different combinations of FeSO4 and Pheroids were foliarly applied on field-grown soybeans in Northern Cape province in South Africa to investigate their influence on seed nutrient composition and yield. Results Confocal and optical microscopy images indicate that FeSO4 or FePO4 was not entrapped in the Pheroids but formed separate precipitates. The average seed Fe of the non-treated plants was 56 ± 3 mg kg−1, and none of the treatments (including the positive controls, FeSO4 and FeSO4 with citrate) significantly increased seed Fe over the control. There was also no significant change in yield or seed Zn, P, protein, or phytic acid. Thus, Pheroids as well as FeSO4 are not suitable as delivery system for Fe to soybean seeds due to Pheroid incompatibility with FeSO4 and poor dispersibility of FePO4. Conclusions Because none of the Fe treatments (including positive controls) affected seed Fe concentrations, foliar Fe application may not be effective to increase seed Fe in crops such as soybean that already have high native Fe.
Publications 1 - 3 of 3