Evaluation of Ethiopian maize cultivars for resistance to Fusarium verticillioides and fumonisin accumulation

The objective of this study was to find sources of resistance to Fusarium ear rot and fumonisin accumulation in maize germplasm. Totally 15 maize cultivars were evaluated by means of silk channel inoculation using a fumonisin producing F. verticillioides isolate in field trials during 2013 and 2014 cropping seasons. Fusarium ear rot severity was determined at harvest, and fumonisin content was quantified using competitive Enzyme Linked Immunosorbent Assay (ELISA). The percentage of infected kernels per maize ear after inoculation, ranged from 5% to 60% in 2013 and from 3% to 40% in 2014. Fumonisin accumulation in maize cultivars ranged from 2700 to 76300 µg/kg in 2013 and from 1800 to 52700 µg/kg in 2014. Maize cultivars Berihu, Melkassa-2, Melkassa-7, Melkassa-4, BHQP542 and MHQ-138 showed low level of ear rot (3.9% to 22.9%) and total fumonisins (2300 to 17300 µg/kg) across the two years experiment. Cultivars that had low disease severity are useful in breeding programs aiming at developing cultivars resistance to fumonisin accumulation

Detection of total fumonisins produced by Fusarium verticillioides (Sacc) isolates from maize kernels in Ethiopia

Fusarium verticillioides is the most common fungal pathogen of maize in Ethiopia. Many strains of this pathogen produce fumonisin myotoxins that are harmful to human and animal health. This study was conducted to determine the fumonisin-producing ability of isolates of F. verticillioides isolated from maize kernels collected from different maize- growing areas of the country. Eighty F. verticillioides isolates were grown on autoclaved maize cultures for one month, and the fumonisin content was quantified using Enzyme Linked Immunosorbent Assay (ELISA). All the 80 isolates evaluated were able to produce detectable levels of total fumonisins in the maize culture with values ranging from 0.25 to 38.01 mg of the toxin per kg of culture material (fungal biomass and maize kernels). The mean levels of total fumonisins produced by the F. verticillioides isolates were not significantly (p>0.05) different among maize growing areas, however, the total fumonisins levels produced by isolates obtained from the same area as well as agroecological zones were wide-ranging. The results indicate that the majority (57.5%) of the F. verticillioides isolates associated with maize grains in Ethiopia produced total fumonisins >4 mg/kg, while 35% of the isolates produced total fumonisins <2 mg/kg. The widespread occurrence of higher fumonisin-producing strains across all maize-growing areas in Ethiopia indicates a possible food safety risk. Thus, efforts should be made to prevent the spread of this fungus with good agronomic practices and to implore all possible ways to avoid maize contamination with fumonisin both in the field and in storage.publishedVersio

Pathogenicity, host specificity and genetic diversity in Norwegian isolates of Microdochium nivale and Microdochium majus

Microdochium majus and Microdochium nivale cause serious disease problems in grasses and cereal crops in the temperate regions. Both fungi can infect the plants during winter (causing pink snow mould) as well as under cool humid conditions during spring and fall. We conducted a pathogenicity test of 15 M. nivale isolates and two M. majus isolates from Norway at low temperature on four different grass cultivars of Lolium perenne and Festulolium hybrids. Significant differences between M. nivale isolates in the ability to cause pink snow mould were detected. The M. nivale strains originally isolated from grasses were more pathogenic than isolates from cereals. The genetic diversity of M. nivale and M. majus isolates was studied by sequencing four genetic regions; Elongation factor-1 alpha (EF-1α), β-tubulin, RNA polymerase II (RPB2) and the Internal Transcribed Spacer (ITS). Phylogenetic trees based on the sequences of these four genetic regions resolved M. nivale and M. majus isolates into separate clades. Higher genetic diversity was found among M. nivale isolates than among M. majus isolates. M. nivale isolates revealed genetic differences related to different host plants (grasses vs. cereals) and different geographic regions (Norway and UK vs. North America). Sequence results from the RPB2 and β-tubulin genes were more informative than those from ITS and EF-1α. The genetic and phenotypic differences detected between Norwegian M. nivale isolates from cereals and grasses support the assumption that host specialization exist within M. nivale isolates.publishedVersio

Global transcriptome changes in perennial ryegrass during early infection by pink snow mould

Lack of resistance to pink snow mould (Microdochium nivale) is a major constraint for adaptation of perennial ryegrass (Lolium perenne L.) to continental regions with long-lasting snow cover at higher latitudes. Almost all investigations of genetic variation in resistance have been performed using cold acclimated plants. However, there may be variation in resistance mechanisms that are functioning independently of cold acclimation. In this study our aim was to identify candidate genes involved in such resistance mechanisms. We first characterized variation in resistance to M. nivale among non-acclimated genotypes from the Norwegian cultivar ‘Fagerlin’ based on relative regrowth and fungal quantification by real-time qPCR. One resistant and one susceptible genotype were selected for transcriptome analysis using paired-end sequencing by Illumina Hiseq 2000. Transcriptome profiles, GO enrichment and KEGG pathway analysis indicate that defense response related genes are differentially expressed between the resistant and the susceptible genotype. A significant up-regulation of defense related genes, as well as genes involved in cell wall cellulose metabolic processes and aryl-alcohol dehydrogenase (NADP+) activity, was observed in the resistant genotype. The candidate genes identified in this study might be potential molecular marker resources for breeding perennial ryegrass cultivars with improved resistance to pink snow mould.publishedVersio

Health and environmental risk evaluation of microorganisms used in bioremediation. Scientific Opinion of the Panel on Microbial Ecology of the Norwegian Scientific Committee for Food Safety

In 2015, The Norwegian Environment Agency requested the Norwegian Scientific Committee for Food Safety (VKM) to collate an overview of bioremediation of polluted ground based on bioaugmentation described in literature for the degradation of various types of pollutants, (including hydrocarbons, heavy metals, chlorinated compounds, explosives etc.).The assessment of genetically modified microorganisms (GMO), phytoremediation, bioremediation based on natural attenuation, bio-stimulation or biodegradation, including composting, are not included in this report

Winter hardiness and management of velvet bentgrass (Agrostis canina) on putting greens in northern environments. Report from the second experimental year 2008

This is a progress report from the second experimental year of the project ‘VELVET GREEN - Winter hardiness and management of velvet bentgrass (Agrostis canina) on putting greens in northern environments’. The report is divided into four main chapters, the first giving results from evaluation of winter hardiness of velvet bentgrass under controlled conditions, the second describing experimental layout and preliminary results from two field trials with fertilizer levels, thatch control methods and topdressing levels; the third describing experimental layout and preliminary results from a lysimeter study on irrigation stategies for velvet bentgrass on greens varying in rootzone composition; and the fourth describing a supplemental experiment evaluating the biological product ‘Thatch-less’ for thatch decomposition.publishedVersio

Winter hardiness and management of velvet bentgrass (Agrostis canina) on putting greens in northern environments. Report from the second experimental year 2008

This is a progress report from the second experimental year of the project ‘VELVET GREEN - Winter hardiness and management of velvet bentgrass (Agrostis canina) on putting greens in northern environments’. The report is divided into four main chapters, the first giving results from evaluation of winter hardiness of velvet bentgrass under controlled conditions, the second describing experimental layout and preliminary results from two field trials with fertilizer levels, thatch control methods and topdressing levels; the third describing experimental layout and preliminary results from a lysimeter study on irrigation stategies for velvet bentgrass on greens varying in rootzone composition; and the fourth describing a supplemental experiment evaluating the biological product ‘Thatch-less’ for thatch decomposition.publishedVersio

Winter hardiness and management of velvet bentgrass (Agrostis canina) on putting greens in northern environments

This is a report from the first experimental year of the project ‘VELVET GREEN - Winter hardiness and management of velvet bentgrass (Agrostis canina) on putting greens in northern environments’. The report is divided into three parts, the first giving results from evaluation of winter hardiness of velvet bentgrass under controlled conditions, the second describing experimental layout and preliminary results from two field trials with fertilizer levels, thatch control methods and topdressing levels; and the third describing experimental layout and preliminary results from a lysimeter study on irrigation stategies for velvet bentgrass on greens varying in rootzone composition.publishedVersio

Testing of alternative plant protection products for the control of Microdochium nivale and other diseases on golf greens. Results from the experimental period 1 October 2011 – 1 March 2013

This progress report presents preliminary results from a project providing data for potential registration of Turf S+ (bacterial product containing Streptomyces) and Turf G+/WPG (fungal product containing Gliocladium catenulatum), both from Interagro BIOS AB, and Vacciplant (seaweed product containing laminarine) from Nordisk Alkali AB, for the control of Microdochium nivale and other diseases on golf greens. Field trials with all three products are carried out on greens in Denmark, Sweden and Norway from 2011 to 2014, and Turf S+ og Turf G+/WPG are also tested in vitro. Half way through the project, none of the test-products have shown any consistent control of M. nivale or any other disease. In the trials at Bioforsk Landvik and Arendal GK, Norway, there was little attack of M. nivale and no significant effect of any treatment, while in the trials at Rungsted GC, Denmark and Kävlinge GC, Sweden, there were massive attacks, but a significant reduction in disease only in the fungicide control treatments. The fifth trial, at Sydsjælland GC, Denmark, had more healthy turf just before snow cover in late November 2012 on plots that had been sprayed the test products, especially with Turf S+ or Vacciplant than on unsprayed control plots, although the turf quality was not as good as in the fungicide control treatment. The first in vitro trial with the microbial agents suggested better effect of both G. catenulatum and Streptomyces sp. on M. nivale at 16 than at 6°C. Possible implications of this for the protocol will be discussed with the manufacturer. The experimental work continues until the summer of 2014.publishedVersio