Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2022
Authors
Michel VerheulAbstract
No abstract has been registered
Authors
Michel VerheulAbstract
No abstract has been registered
Authors
Amos Samkumar Katja Karppinen Tony K. McGhie Richard V. Espley Inger Martinussen Laura JaakolaAbstract
Light spectral quality is known to affect flavonoid biosynthesis during fruit ripening. However, the response of fruits to different light conditions, when ripening autonomously from the parent plant (detached), has been less explored. In this study, we analyzed the effect of light quality on detached and naturally ripening (attached) non-climacteric wild bilberry (Vaccinium myrtillus L.) fruits accumulating high amounts of anthocyanins and flavonols. Our results indicated contrasting responses for the accumulation of phenolic compounds in the berries in response to red and blue light treatments. For detached berries, supplemental blue light resulted in the highest accumulation of anthocyanins, while naturally ripening berries had elevated accumulation under supplemental red light treatment. Both red and blue supplemental light increased the expression levels of all the major structural genes of the flavonoid pathway during ripening. Notably, the key regulatory gene of anthocyanin biosynthesis, VmMYBA1, was found to express fivefold higher under blue light treatment in the detached berries compared to the control. The red light treatment of naturally ripening berries selectively increased the delphinidin branch of anthocyanins, whereas in detached berries, blue light increased other anthocyanin classes along with delphinidins. In addition, red and far-red light had a positive influence on the accumulation of flavonols, especially quercetin and myricetin glycoside derivatives, in both ripening conditions. Our results of differential light effects on attached and detached berries, which lacks signaling from the mother plant, provide new insights in understanding the light-mediated regulatory mechanisms in non-climacteric fruit ripening.
Abstract
In total, 154 wild raspberry samples were collected from 26 localities representing a large area in Norway (21 localities) and a narrowly defined region of the Giant Mountains in the northern parts of the Czech Republic (5 localities). The samples were characterized for genetic diversity and population differentiation as well as for their potential use in crop breeding. Choice of plant material was based on the biogeographical similarity between the Giant Mountains and relevant areas in Norway, where plant communities may have evolved in parallel since the ice ages. The overall level of genetic diversity ĥ = 0.786, I = 2.153 was high. Numerous rare alleles were found for raspberries originating especially from the East Giant Mountains populations Jeleni louky and Krakonosuv lom. The overall degree of population subdivision measured by Wright’s fixation index (FST) was of a moderate level of 0.28. The highest level 0.33 was found between populations in Northern Norway and 0.31 between populations in the Giant Mountains. The genetic structure was evaluated using Bayesian analyses as implemented using STRUCTURE software. According to the ΔK value, eight clusters (K8) were identified among all the analysed samples. The results of the analysis of molecular variance (AMOVA) indicated that 79.7% of the total variation could be attributed to differences among individuals within populations, 15.3% was credited to differences among populations within regions, and only 5.0% was attributed to differences among regions. We concluded based on the results that Czech and Norwegian raspberry (R. idaeus) populations growing in natural high altitude and northern ecosystems are important genetic resources and represent a valuable source of genes and unique allele compositions for in situ and ex situ conservation and future raspberry breeding programmes.
Abstract
Bilberry fruit is regarded as one of the best natural sources of anthocyanins and is widely explored for its health-beneficial compounds. Besides anthocyanins, one of the major attributes that determine the berry quality is the accumulation of sugars that provide sweetness and flavor to ripening fruit. In this study, we have identified 25 sugar metabolism-related genes in bilberry, including invertases (INVs), hexokinases (HKs), fructokinases (FKs), sucrose synthases (SSs), sucrose phosphate synthases (SPSs), and sucrose phosphate phosphatases (SPPs). The results indicate that isoforms of the identified genes are expressed differentially during berry development, suggesting specialized functions. The highest sugar content was found in ripe berries, with fructose and glucose dominating accompanied by low sucrose amount. The related enzyme activities during berry development and ripening were further analyzed to understand the molecular mechanism of sugar accumulation. The activity of INVs in the cell wall and vacuole increased toward ripe berries. Amylase activity involved in starch metabolism was not detected in unripe berries but was found in ripe berries. Sucrose resynthesizing SS enzyme activity was detected upon early ripening and had the highest activity in ripe berries. Interestingly, our transcriptome data showed that supplemental irradiation with red and blue light triggered upregulation of several sugar metabolism-related genes, including α- and β-amylases. Also, differential expression patterns in responses to red and blue light were found across sucrose, galactose, and sugar-alcohol metabolism. Our enzymological and transcriptional data provide new understanding of the bilberry fruit sugar metabolism having major effect on fruit quality.
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
Acrylamide has become an important measure when looking at profitability and sustainability in the potato processing industry. Acrylamide is a possible carcinogenic which is formed in starchy foods during high-temperature cooking processes. Crisps and French fries made from processing potatoes are consumed by people of all ages and therefore the pressure on the industry has been large to reduce the acrylamide levels. In the ongoing project POTETFRIT (2019-2022), the aim is to reduce acrylamide content and improve product quality, profitability and sustainability in the production of Norwegian crisps and French fries. The aim will be reached through new knowledge about the interaction between potato quality and storage conditions. The effect of different temperature strategies including cold storage (5 ⁰C) and reconditioning at 15 ⁰C was tested in eight different varieties (Lady Claire, Kiebitz, Pirol, Lady Britta, Peik, Innovator, Zorba and Gullflaks). The importance of elevated CO2 levels in the potato store on product quality and acrylamide content, was studied in the same potato varieties and in tubers with different maturity levels. Storage conditions in 29 commercial potato stores was also studied, with attention to temperature conditions and CO2 levels in different stages of the storage season. The effect of different ventilation strategies was also studied. So far results show that the varieties L. Claire, Kiebitz and Gullflaks can be stored at low temperature levels without developing high sugar and acrylamide levels and dark fry colour and at the same time keeping sprouting at a low level. In the CO2 trials, none of the varieties tested showed elevated sugar and acrylamide levels when exposed to high CO2 levels (15000 ppm) and also in the commercial stores there was no correlation between high CO2 and high sugar levels.
Abstract
No abstract has been registered
Authors
Pia Heltoft ThomsenAbstract
No abstract has been registered