Browsing by Subject "disease resistance"

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  • Jaber, Emad; Kovalchuk, Andriy; Raffaello, Tommaso; Keriö, Susanna; Teeri, Teemu; Asiegbu, Fred O. (2018)
    Both the establishment of sustainable forestry practices and the improvement of commercially grown trees require better understanding of mechanisms used by forest trees to combat microbial pathogens. We investigated the contribution of a gene encoding Scots pine (Pinus sylvestris L.) antimicrobial protein Sp-AMP2 (PR-19) to the host defenses to evaluate the potential of Sp-AMP genes as molecular markers for resistance breeding. We developed transgenic tobacco plants expressing the Sp-AMP2 gene. Transgenic plants showed a reduction in the size of lesions caused by the necrotrophic pathogen Botrytis cinerea. In order to investigate Sp-AMP2 gene expression level, four transgenic lines were tested in comparison to control and non-transgenic plants. No Sp-AMP2 transcripts were observed in any of the control and non-transgenic plants tested. The transcript of Sp-AMP2 was abundantly present in all transgenic lines. Sp-AMP2 was induced highly in response to the B. cinerea infection at 3 d.p.i. This study provides an insight into the role of Sp-AMP2 and its functional and ecological significance in the regulation of plant–pathogen interactions.
  • Kjaerner-Semb, Erik; Edvardsen, Rolf B.; Ayllon, Fernando; Vogelsang, Petra; Furmanek, Tomasz; Rubin, Carl Johan; Veselov, Alexey E.; Nilsen, Tom Ole; McCormick, Stephen D.; Primmer, Craig R.; Wargelius, Anna (2021)
    Most Atlantic salmon (Salmo salarL.) populations follow an anadromous life cycle, spending early life in freshwater, migrating to the sea for feeding, and returning to rivers to spawn. At the end of the last ice age similar to 10,000 years ago, several populations of Atlantic salmon became landlocked. Comparing their genomes to their anadromous counterparts can help identify genetic variation related to either freshwater residency or anadromy. The objective of this study was to identify consistently divergent loci between anadromous and landlocked Atlantic salmon strains throughout their geographical distribution, with the long-term aim of identifying traits relevant for salmon aquaculture, including fresh and seawater growth, omega-3 metabolism, smoltification, and disease resistance. We used a Pool-seq approach (n = 10-40 individuals per population) to sequence the genomes of twelve anadromous and six landlocked Atlantic salmon populations covering a large part of the Northern Hemisphere and conducted a genomewide association study to identify genomic regions having been under different selection pressure in landlocked and anadromous strains. A total of 28 genomic regions were identified and includedcadm1on Chr 13 andppargc1aon Chr 18. Seven of the regions additionally displayed consistently reduced heterozygosity in fish obtained from landlocked populations, including the genes gpr132, cdca4, and sertad2 on Chr 15. We also found 16 regions, includingigf1on Chr 17, which consistently display reduced heterozygosity in the anadromous populations compared to the freshwater populations, indicating relaxed selection on traits associated with anadromy in landlocked salmon. In conclusion, we have identified 37 regions which may harbor genetic variation relevant for improving fish welfare and quality in the salmon farming industry and for understanding life-history traits in fish.
  • Mykrä, Emmi (Helsingfors universitet, 2013)
    Oat (Avena sativa L.) is a crop grown for feed and for food industry. It is the most used fodder plant after barley in Finland and is also exported. In 2011, oat was grown on 308 200 hectares in Finland and the average yield per hectare was 3390 kg. Several fungal and virus diseases cause remarkable crop losses in oats. Especially in the temperate zone, the most common disease is the head blight caused by Fusarium species. These fungi overwinter as mycelium or spores and produce mycotoxins. In Finland, F. culmorum is a common DON toxin producer and F. langsethiae is a T-2/HT-2 toxin producer in oats. Toxins affect the quality of oat yield and can make it unsuitable for use. Therefore, the amounts of mycotoxin allowed in cereals are stipulated by food safety authorities. This thesis was a part of MTT Agrifood Research Finland’s Hyötygeeni project. The aim of the research was to study resistance of eight oat cultivars to F. culmorum and F. langsethiae. Indicators of resistance were germination of the infested seeds, the proportion of infected seeds and the amounts of mycotoxins. The trials were made in greenhouse with artificial inoculations. The results indicated that four cultivars expressed similar levels of resistance to both Fusarium species. Three cultivars had better resistance to F. langsethiae than F. culmorum and only one cultivar had better resistance to F. culmorum than F. langsethiae. In future research, the results can be utilized in resistance breeding. Global warming will increase the risk of plant diseases. On that account importance of breeding will be emphasized.
  • Ohralahti, Kalle (Helsingfors universitet, 2013)
    Barley is the most cultivated cereal in acreage in Finland. Barley has many plant diseases that cause yield reductions like net blotch, scald and mildew. The weather conditions and the disease resistance of the cultivar are affecting the appearance of the plant diseases. Plant diseases can be controlled by certified seed, seed treatment, crop rotation, fungicide treatment and by cultivating resistant cultivars. Net blotch causes reduction in green leaf area, thousand grain weight and thereby it reduces yield. The aim of this study was to study what is the yield response of barley to fungicide treatment when cultivars are either susceptible or tolerant to net blotch. The data of this study was based on The profitability of plant protection -trial series. The field trials were conducted at three locations in Finland during 2006–2009. The cultivars in the trials were divided based on their net blotch resistance to susceptible and tolerant groups. Fungicide treatment was made with Acanto Prima as a single treatment at the flag leaf stage. Tolerant and susceptible groups differed significantly in the amount of the net blotch. Fungicide treatment decreased the appearance of net blotch more in the susceptible group although the amount of net blotch was significantly less in the tolerant group. In the tolerant group the disease level was low even before the fungicide treatment. The conclusions of this study were, that tolerant cultivar group had better yield, but susceptible cultivar group had better yield response to the fungicide treatment. The yield response was in average 400 kg/ha in the susceptible and about 200 kg/ha in the resistant cultivar group. The yield response was due to the higher thousand grain weight. The yield security of disease resistant cultivar is better also in higher disease pressure. Resistant cultivar is one way to reduce the usage of plant protection products in IPM farming. Breeding of resistant cultivars is needed because the plant diseases are altering in their disease infection capability.