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NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.

2025

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Abstract Bilberry ( Vaccinium myrtillus L.) fruit are one of the best natural sources of anthocyanins. Anthocyanin and flavonoid biosynthesis are transcriptionally regulated by the conserved MBW complex, including R2R3 MYB, basic helix-loop-helix (bHLH) and WD40 proteins. In this study, homology-search in the bilberry genome identified three putative anthocyanin biosynthesis-regulating bHLH genes, all containing a MYB binding domain, indicating their possible interaction with R2R3 MYBs. Phylogenetic analysis assigned the VmbHLHs to three different clusters within the IIIf subgroup of bHLHs. The expression of VmbHLH2 elevated at berry ripening, while VmbHLH1 and VmbHLH3 showed decreasing expression towards berry maturation. When transiently overexpressed together with MdMYB10 in Nicotiana benthamiana leaves, VmbHLH2 and VmbHLH3 were able to complement MdbHLH3 and upregulate a full set of anthocyanin biosynthetic genes leading to anthocyanin accumulation. In contrast, VmbHLH1 induced a reduced set of flavonoid pathway genes. Our results provide the first functional characterization of flavonoid-regulating bHLHs that contribute to the MBW complex in the economically important genus Vaccinium. We propose that the TT8-type VmbHLH2 is involved in anthocyanin biosynthesis in ripening bilberry fruit, while the MYC1-type VmbHLH1 and GL3/EGL3-type VmbHLH3 are associated with anthocyanin and PA biosynthesis, mainly in tissues other than berries.

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Abstract The cuticle and cuticular waxes play vital roles as the interface between a plant and its environment. Cuticular waxes are composed of very long-chain fatty acids (VLCFAs) and their derivatives as well as triterpenoids, which are specialized metabolites. Although triterpenoids constitute a major fraction of cuticular waxes, their functions remain poorly understood. In this review, we provide an overview of the chemical diversity of triterpenoids in the cuticular waxes of leaves and fruits of angiosperms and discuss changes in triterpenoid content during their development. The methods and challenges for the analysis of cuticular wax triterpenoids are summarized. The biosynthesis of triterpenoids is also reviewed along with recent knowledge of the potential mechanisms of triterpenoid transportation and secretion from the site of biosynthesis to the plant surface. Considering ongoing climate change, the current understanding of the effects of environmental conditions and abiotic stress factors on cuticular wax triterpenoids is reviewed. We also present an overview of the current knowledge on the roles of triterpenoids in cuticular waxes in transpiration and defense against biotic stressors and their possible role in cuticle stabilization. Moreover, owing to the generally high levels of triterpenoids in fruit cuticular waxes, the provided information on the variation and role of cuticular wax triterpenoids during postharvest fruit storage might help in the development of strategies for better fruit quality maintenance and preservation.

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A number of modelling frameworks exist to estimate resilience from ecological datasets. A subset of these frameworks seeks to estimate the whole ‘stability landscape', which can be used to calculate resilience and identify stable states and tipping points. These methods provide opportunities for insights into possible causes and consequences of variation in ecosystem resilience and dynamics. However, because such models can be complex to implement, there has so far been a substantial barrier to their application in ecological research. Here, we present the ‘mixglm' package for R software, which parametrizes stability landscapes using a mixture model approach. It provides tools for the calculation of resilience, identification of stable states and tipping points, as well as visualization functions. Flexible model specification allows the mean, precision, and probability of each mixture component to be linked to multiple predictors, such as environmental covariates. ‘mixglm' is based on Bayesian inference via NIMBLE and supports normal, beta, gamma, and negative binomial distributed response variables. We illustrate the use of ‘mixglm' with a published case of tree cover in South America, which reports a stability landscape with distinct stable states. Using ‘mixglm', we replicated the identification of these states. Moreover, we quantified the uncertainty of our estimates, and computed resilience estimates of South America's forests. We also conducted a power analysis to provide guidance regarding required sample sizes. ‘mixglm' can be readily used to describe stability landscapes and identify stable states in most spatial datasets, and it is accompanied by tools for the calculation of resilience estimates.