| 1. |
- Chowdhury, Jamil, et al.
(författare)
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Laccaria bicolor pectin methylesterases are involved in ectomycorrhiza development with Populus tremula × Populus tremuloides
- 2022
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Ingår i: New Phytologist. - : John Wiley & Sons. - 0028-646X .- 1469-8137. ; 236:2, s. 639-655
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Tidskriftsartikel (refereegranskat)abstract
- The development of ectomycorrhizal (ECM) symbioses between soil fungi and tree roots requires modification of root cell walls. The pectin-mediated adhesion between adjacent root cells loosens to accommodate fungal hyphae in the Hartig net, facilitating nutrient exchange between partners. We investigated the role of fungal pectin modifying enzymes in Laccaria bicolor for ECM formation with Populus tremula × Populus tremuloides.We combine transcriptomics of cell-wall-related enzymes in both partners during ECM formation, immunolocalisation of pectin (Homogalacturonan, HG) epitopes in different methylesterification states, pectin methylesterase (PME) activity assays and functional analyses of transgenic L. bicolor to uncover pectin modification mechanisms and the requirement of fungal pectin methylesterases (LbPMEs) for ECM formation.Immunolocalisation identified remodelling of pectin towards de-esterified HG during ECM formation, which was accompanied by increased LbPME1 expression and PME activity. Overexpression or RNAi of the ECM-induced LbPME1 in transgenic L. bicolor lines led to reduced ECM formation. Hartig Nets formed with LbPME1 RNAi lines were shallower, whereas those formed with LbPME1 overexpressors were deeper.This suggests that LbPME1 plays a role in ECM formation potentially through HG de-esterification, which initiates loosening of adjacent root cells to facilitate Hartig net formation.
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| 2. |
- Lindberg, A., et al.
(författare)
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Cold stress stimulates algae to produce value-added compounds
- 2022
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Ingår i: Bioresource Technology Reports. - : Elsevier. - 2589-014X. ; 19
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Tidskriftsartikel (refereegranskat)abstract
- Two cold-tolerant microalgae, Chlorella vulgaris and Scenedesmus sp., were grown at 22 and 5 °C. At the lower temperature, the microalgae showed substantial biochemical and morphological changes. The soluble sugar profile in response to low-temperature cultivation was very different in the two strains. C. vulgaris increased both the sucrose and raffinose family oligosaccharides (RFOs) content at 5 °C while Scenedesmus sp. drastically reduced the sucrose content. Both strains increased the total fatty acid methyl ester (FAME) content when grown at 5 °C. However, the FAME profiles were very different: C. vulgaris mainly increased C18:1 and less so C18:3, while Scenedesmus sp. decreased C18:1 but greatly increased C18:3. The morphology of C. vulgaris changed slightly at the lower temperature, while Scenedesmus sp. showed substantial changes in the size and shape. Low temperature triggered the synthesis of unsaturated fatty acids that are essential for human nutrition.
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| 3. |
- Niemi, Calle, et al.
(författare)
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Quantitative and qualitative saccharide analysis of North Atlantic brown seaweed by gas chromatography/mass spectrometry and infrared spectroscopy
- 2024
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Ingår i: International Journal of Biological Macromolecules. - : Elsevier. - 0141-8130 .- 1879-0003. ; 254
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Tidskriftsartikel (refereegranskat)abstract
- Brown seaweeds contain a variety of saccharides which have potential industrial uses. The most abundant polysaccharide in brown seaweed is typically alginate, consisting of mannuronic (M) and guluronic acid (G). The ratio of these residues fundamentally determines the physicochemical properties of alginate. In the present study, gas chromatography/mass spectrometry (GC/MS) was used to give a detailed breakdown of the monosaccharide species in North Atlantic brown seaweeds. The anthrone method was used for determination of crystalline cellulose. The experimental data was used to calibrate multivariate prediction models for estimation of total carbohydrates, crystalline cellulose, total alginate and alginate M/G ratio directly in dried, brown seaweed using three types of infrared spectroscopy, using relative error (RE) as a measure of predictive accuracy. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) performed well for the estimation of total alginate (RE = 0.12, R2 = 0.82), and attenuated total reflectance (ATR) showed good prediction of M/G ratio (RE = 0.14, R2 = 0.86). Both DRIFTS, ATR and near infrared (NIR) were unable to predict crystalline cellulose and only DRIFTS performed better in determining total carbohydrates. Multivariate spectral analysis is a promising method for easy and rapid characterization of alginate and M/G ratio in seaweed.
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| 4. |
- Oliveira de Sousa, Dannylo, et al.
(författare)
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Effects of grass species on cell wall components and milk production of dairy cows
- 2023
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Ingår i: Report from the Department of Crop Production Ecology (VPE). - 1653-5375. ; , s. 105-108
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- There is a balance between dry matter (DM) yield and feed value when choosing types of grasses on a farm depending on the acreages of farmland and types of ruminants to be fed. Tall fescue (TF, Festuca arundinacea Schreb.) appears to be an alternative to traditional grasses, such as timothy (TI, Phleum pretense L.) and meadow fescue (MF, Festuca pratensis L.), in northern Europe. This is especially important in a changing climate due to its high DM yield, drought tolerance and adaptability to a wide range of climates (Richard et al., 2020). Our previous study (Sousa et al., 2021) compared the effects of TI and TF on cell wall composition and their relationship to dairy cow performance. Besides the greater concentration of fiber components observed in TI, concentrations of most of the hydroxylcinnamic acids (p-coumaric acid, ferulic acid, and its respective cis isomerisation) in the cell walls were greater in TF silages than in TI silages. Consequently, cows receiving TI silages showed greater energy corrected milk (ECM) yield than cows receiving TF silages, suggesting that the concentration of hydroxycinnamic acids was the main factor regulating milk production. To our knowledge, there is no study comparing TF and TI with MF on performance of dairy cows. Therefore, the objective of this study was to evaluate the effect of these grass species on cell wall components and milk production of dairy cows.
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| 5. |
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| 6. |
- Takahashi Schmidt, Junko, et al.
(författare)
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ELIMAKI Locus Is Required for Vertical Proprioceptive Response in Birch Trees
- 2020
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Ingår i: Current Biology. - : Elsevier BV. - 0960-9822 .- 1879-0445. ; 30, s. 589-599
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Tidskriftsartikel (refereegranskat)abstract
- Tree architecture has evolved to support a top-heavy above-ground biomass, but this integral feature poses a weight-induced challenge to trunk stability. Maintaining an upright stem is expected to require vertical proprioception through feedback between sensing stem weight and responding with radial growth. Despite its apparent importance, the principle by which plant stems respond to vertical loading forces remains largely unknown. Here, by manipulating the stem weight of downy birch (Betula pubescens) trees, we show that cambial development is modulated systemically along the stem. We carried out a genetic study on the underlying regulation by combining an accelerated birch flowering program with a recessive mutation at the ELIMAKI locus (EKI), which causes a mechanically defective response to weight stimulus resulting in stem collapse after just 3 months. We observed delayed wood morphogenesis in eki compared with WT, along with a more mechanically elastic cambial zone and radial compression of xylem cell size, indicating that rapid tissue differentiation is critical for cambial growth under mechanical stress. Furthermore, the touch-induced mechanosensory pathway was transcriptionally misregulated in eki, indicating that the ELIMAKI locus is required to integrate the weight-growth feedback regulation. By studying this birch mutant, we were able to dissect vertical proprioception from the gravitropic response associated with reaction wood formation. Our study provides evidence for both local and systemic responses to mechanical stimuli during secondary plant development.
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| 7. |
- Vaisanen, E., et al.
(författare)
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Hunting monolignol transporters: membrane proteomics and biochemical transport assays with membrane vesicles of Norway spruce
- 2020
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Ingår i: Journal of Experimental Botany. - : Oxford University Press (OUP). - 0022-0957 .- 1460-2431. ; 71:20, s. 6379-6395
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Tidskriftsartikel (refereegranskat)abstract
- Both the mechanisms of monolignol transport and the transported form of monolignols in developing xylem of trees are unknown. We tested the hypothesis of an active, plasma membrane-localized transport of monolignol monomers, dimers, and/or glucosidic forms with membrane vesicles prepared from developing xylem and lignin-forming tissuecultured cells of Norway spruce (Picea abies L. Karst.), as well as from control materials, comprising non-lignifying Norway spruce phloem and tobacco (Nicotiana tabacum L.) BY-2 cells. Xylem and BY-2 vesicles transported both coniferin and p-coumaryl alcohol glucoside, but inhibitor assays suggested that this transport was through the tonoplast. Membrane vesicles prepared from lignin-forming spruce cells showed coniferin transport, but the K-m value for coniferin was much higher than those of xylem and BY-2 cells. Liquid chromatography-mass spectrometry analysis of membrane proteins isolated from spruce developing xylem, phloem, and lignin-forming cultured cells revealed multiple transporters. These were compared with a transporter gene set obtained by a correlation analysis with a selected set of spruce monolignol biosynthesis genes. Biochemical membrane vesicle assays showed no support for ABC-transporter-mediated monolignol transport but point to a role for secondary active transporters (such as MFS or MATE transporters). In contrast, proteomic and co-expression analyses suggested a role for ABC transporters and MFS transporters.
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