Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    We will mail you new results for this query: keywords==ultraviolet-b radiation
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Beneficial microbes in a changing environment: are they always helping plants to deal with insects?
Pineda, A. ; Dicke, M. ; Pieterse, C.M.J. ; Pozo, M.J. - \ 2013
Functional Ecology 27 (2013)3. - ISSN 0269-8463 - p. 574 - 586.
arbuscular mycorrhizal symbiosis - ultraviolet-b radiation - abscisic-acid - climate-change - induced resistance - defense responses - water-stress - signaling pathways - fungal endophyte - salicylic-acid
Plants have a complex immune system that defends them against attackers (e.g. herbivores and microbial pathogens) but that also regulates the interactions with mutualistic organisms (e.g. mycorrhizal fungi and plant growth-promoting rhizobacteria). Plants have to respond to multiple environmental challenges, so they need to integrate both signals associated with biotic and abiotic stresses in the most appropriate response to survive. Beneficial microbes such as rhizobacteria and mycorrhizal fungi can help plants to deal' with pathogens and herbivorous insects as well as to tolerate abiotic stress. Therefore, beneficial microbes may play an important role in a changing environment, where abiotic and biotic stresses on plants are expected to increase. The effects of beneficial microbes on herbivores are highly context-dependent, but little is known on what is driving such dependency. Recent evidence shows that abiotic stresses such as changes in soil nutrients, drought and salt stress, as well as ozone can modify the outcome of plantmicrobeinsect interactions. Here, we review how abiotic stress can affect plantmicrobe, plantinsect and plantmicrobeinsect interactions, and the role of the network of plant signal-transduction pathways in regulating such interactions. Most of the studies on the effects of abiotic stress on plantmicrobeinsect interactions show that the effects of microbes on herbivores (positive or negative) are strengthened under stressful conditions. We propose that, at least in part, this is due to the crosstalk of the different plant signalling pathways triggered by each stress individually. By understanding the cross-regulation mechanisms we may be able to predict the possible outcomes of plant-microbeinsect interactions under particular abiotic stress conditions. We also propose that microbes can help plants to deal with insects mainly under conditions that compromise efficient activation of plant defences. In the context of global change, it is crucial to understand how abiotic stresses will affect species interactions, especially those interactions that are beneficial for plants. The final aim of this review is to stimulate studies unravelling when these beneficial' microbes really benefit a plant.
MYB8 Controls Inducible Phenolamide Levels by Activating Three Novel Hydroxycinnamoyl-Coenzyme A:Polyamine Transferases in Nicotiana attenuata[W][OA]
Onkokesung, N. ; Gaquerel, E. ; Kotkar, H. ; Kaur, H. ; Baldwin, I.T. ; Galis, I. - \ 2012
Plant Physiology 158 (2012)1. - ISSN 0032-0889 - p. 389 - 407.
ultraviolet-b radiation - transcription factor - plant defense - acid-amides - convergent evolution - simulated herbivory - insect herbivores - responses - tobacco - metabolism
A large number of plants accumulate N-acylated polyamines (phenolamides [PAs]) in response to biotic and/or abiotic stress conditions. In the native tobacco (Nicotiana attenuata), the accumulation of two major PAs, caffeoylputrescine and dicaffeoylspermidine (DCS), after herbivore attack is known to be controlled by a key transcription factor, MYB8. Using a broadly targeted metabolomics approach, we show that a much larger spectrum of PAs composed of hydroxycinnamic acids and two polyamines, putrescine and spermidine, is regulated by this transcription factor. We cloned several novel MYB8-regulated genes, annotated as putative acyltransferases, and analyzed their function. One of the novel acyltransferases (AT1) is shown to encode a hydroxycinnamoyl-coenzyme A:putrescine acyltransferase responsible for caffeoylputrescine biosynthesis in tobacco. Another gene (acyltransferase DH29), specific for spermidine conjugation, mediates the initial acylation step in DCS formation. Although this enzyme was not able to perform the second acylation toward DCS biosynthesis, another acyltransferase gene, CV86, proposed to act on monoacylated spermidines, was isolated and partially characterized. The activation of MYB8 in response to herbivore attack and associated signals required the activity of LIPOXYGENASE3, a gene involved in jasmonic acid (JA) biosynthesis in N. attenuata. These new results allow us to reconstruct a complete branch in JA signaling that defends N. attenuata plants against herbivores: JA via MYB8’s transcriptional control of AT1 and DH29 genes controls the entire branch of PA biosynthesis, which allows N. attenuata to mount a chemically diverse (and likely efficient) defense shield against herbivores.
2-D DIGE analysis of UV-C radiation-responsive proteins in globe artichoke leaves
Falvo, S. ; Carli, M. Di; Desiderio, A. ; Benvenuto, E. ; Moglia, A. ; America, A.H.P. ; Lanteri, S. ; Acquadro, A. - \ 2012
Proteomics 12 (2012)3. - ISSN 1615-9853 - p. 448 - 460.
ultraviolet-b radiation - heat-shock proteins - proteome analysis - plants - stress - metabolism - rice - photorespiration - photooxidation - biosynthesis
Plants respond to ultraviolet stress inducing a self-defence through the regulation of specific gene family members. The UV acclimation is the result of biochemical and physiological processes, such as enhancement of the antioxidant enzymatic system and accumulation of UV-absorbing phenolic compounds (e.g. flavonoids). Globe artichoke is an attractive species for studying the protein network involved in UV stress response, being characterized by remarkable levels of inducible antioxidants. Proteomic tools can assist the evaluation of the expression patterns of UV-responsive proteins and we applied the difference in-gel electrophoresis (DIGE) technology for monitoring the globe artichoke proteome variation at four time points following an acute UV-C exposure. A total of 145 UV-C-modulated proteins were observed and 119 were identified by LC-MS/MS using a ~144¿000 customized Compositae protein database, which included about 19¿000 globe artichoke unigenes. Proteins were Gene Ontology (GO) categorized, visualized on their pathways and their behaviour was discussed. A predicted protein interaction network was produced and highly connected hub-like proteins were highlighted. Most of the proteins differentially modulated were chloroplast located, involved in photosynthesis, sugar metabolisms, protein folding and abiotic stress. The identification of UV-C-responsive proteins may contribute to shed light on the molecular mechanisms underlying plant responses to UV stress
Photosynthetic control of electron transport and the regulation of gene expression
Foyer, C.H. ; Neukermans, J. ; Queval, G. ; Noctor, G. ; Harbinson, J. - \ 2012
Journal of Experimental Botany 63 (2012)4. - ISSN 0022-0957 - p. 1637 - 1661.
atmospheric carbon-dioxide - long-term exposure - water-water cycle - ribulose-1,5-bisphosphate carboxylase-oxygenase - excess excitation-energy - ultraviolet-b radiation - nitrogen-use efficiency - mg-protoporphyrin ix - co2 enrichment face - photosystem-i
The term ‘photosynthetic control’ describes the short- and long-term mechanisms that regulate reactions in the photosynthetic electron transport (PET) chain so that the rate of production of ATP and NADPH is coordinated with the rate of their utilization in metabolism. At low irradiances these mechanisms serve to optimize light use efficiency, while at high irradiances they operate to dissipate excess excitation energy as heat. Similarly, the production of ATP and NADPH in ratios tailored to meet demand is finely tuned by a sophisticated series of controls that prevents the accumulation of high NAD(P)H/NAD(P) ratios and ATP/ADP ratios that would lead to potentially harmful over-reduction and inactivation of PET chain components. In recent years, photosynthetic control has also been extrapolated to the regulation of gene expression because mechanisms that are identical or similar to those that serve to regulate electron flow through the PET chain also coordinate the regulated expression of genes encoding photosynthetic proteins. This requires coordinated gene expression in the chloroplasts, mitochondria, and nuclei, involving complex networks of forward and retrograde signalling pathways. Photosynthetic control operates to control photosynthetic gene expression in response to environmental and metabolic changes. Mining literature data on transcriptome profiles of C3 and C4 leaves from plants grown under high atmospheric carbon dioxide (CO2) levels compared with those grown with ambient CO2 reveals that the transition to higher photorespiratory conditions in C3 plants enhances the expression of genes associated with cyclic electron flow pathways in Arabidopsis thaliana, consistent with the higher ATP requirement (relative to NADPH) of photorespiration.
Evidence for the semireduced primary quinone electron acceptor of photosystem II being a photosensitizer for UVB damage to the photosynthetic apparatus
Rodrigues, G.C. ; Jansen, M.A.K. ; Noort, M.E. van den; Rensen, J.J.S. van - \ 2006
Plant Science 170 (2006)2. - ISSN 0168-9452 - p. 283 - 290.
ultraviolet-b radiation - triazine-resistant - chloroplast reactions - active radiation - reducing side - d2 protein - degradation - photoinhibition - leaves - donor
Exposure to ultraviolet-B radiation (UVB) radiation affects plants in multiple ways, including effects on the photosynthetic apparatus. The carbon dioxide reduction reactions are affected as well as the light reactions, especially those of photosystem II. In the literature several UVB chromophores are suggested, including redox-active tyrosines, plastosemiquinones, and the manganese cluster of the water-splitting complex. We measured the damage by UVB radiation given together with a small component of photosynthetically active radiation (PAR) in a triazine-resistant biotype and a wild-type of Chenopodium album. The damage was estimated by chlorophyll fluorescence measurements and was larger in the resistant plants. We were able to show that the concentration of the semireduced primary quinone electron acceptor of photosystem II is higher in the resistant plants, under all radiation conditions tested. This finding and additional results support the hypothesis that plastosemiquinones are photosensitizers for UVB radiation
Negative effects of UVB-irradiated phytoplankton on life history traits and fitness of Daphnia magna
Lange, H.J. de; Reeuwijk, P.L. van - \ 2003
Freshwater Biology 48 (2003). - ISSN 0046-5070 - p. 678 - 686.
ultraviolet-b radiation - fatty-acid composition - food quality - offspring fitness - pulex - zooplankton - algae - consequences - depletion - survival
1. We tested the effect of ultraviolet-B (UVB)-irradiated phytoplankton on life history characteristics of Daphnia magna . Two phytoplankton species were used, Chlamydomonas reinhardtii and Cryptomonas pyrenoidifera . The phytoplankton species were cultured under photosynthetically active radiation (PAR) conditions, and under PAR supplemented with ultraviolet-A and ultraviolet-B radiation, and fed to Daphnia . 2. Life history traits of Daphnia were negatively affected when fed on UVB-irradiated Cryptomonas . Size at maturity was depressed and fewer juveniles with lower fitness were produced in the UVB treatments. In the Chlamydomonas experiment, no significant effects were found. 3. The cause of the observed UVB effects is likely to be constraints in food quality. Ultraviolet-B radiation thus has the potential of inhibiting energy transfer from the first to the second trophic level.
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