"Hoe houden we de herontdekking van de natuur in leven?"
Buijs, Arjen - \ 2020
nature - experiential value - natural areas - Netherlands - leisure
Variation in plant-mediated interactions between rhizobacteria and caterpillars: potential role of soil composition
Pangesti, N.P.D. ; Pineda Gomez, A.M. ; Dicke, M. ; Loon, J.J.A. van - \ 2015
Plant Biology 17 (2015)2. - ISSN 1435-8603 - p. 474 - 483.
induced systemic resistance - arbuscular mycorrhizal symbiosis - arabidopsis-thaliana - insect herbivores - gene-expression - jasmonic acid - pseudomonas-fluorescens - microbes - bacteria - immunity
Selected strains of non-pathogenic rhizobacteria can trigger induced systemic resistance (ISR) in plants against aboveground insect herbivores. However, the underlying mechanisms of plant-mediated interactions between rhizobacteria and herbivorous insects are still poorly understood. Using Arabidopsis thaliana Col-0-Pseudomonas fluorescens WCS417r as a model system, we investigated the performance and the molecular mechanisms underlying plant-mediated effects of rhizobacteria on the generalist caterpillar Mamestra brassicae and the specialist Pieris brassicae. Rhizobacteria colonisation of Arabidopsis roots resulted in decreased larval weight of M. brassicae, whereas no effect was observed on larval weight of P. brassicae. Using a jasmonic acid (JA)-impaired mutant (dde2-2), we confirmed the importance of JA in rhizobacteria-mediated ISR against M. brassicae. Interestingly, in some experiments we also observed rhizobacteria-induced systemic susceptibility to M. brassicae. The role of soil composition in the variable outcomes of microbe-plant-insect interactions was then assessed by comparing M. brassicae performance and gene transcription in plants grown in potting soil or a mixture of potting soil and sand in a 1:1 ratio. In a mixture of potting soil and sand, rhizobacteria treatment had a consistent negative effect on M. brassicae, whereas the effect was more variable in potting soil. Interestingly, at 24 h post-infestation (hpi) rhizobacteria treatment primed plants grown in a mixture of potting soil and sand for stronger expression of the JA- and ethylene-regulated genes PDF1.2 and HEL, respectively. Our study shows that soil composition can modulate rhizobacteria-plant-insect interactions, and is a factor that should be considered when studying these belowground-aboveground interactions.
Rhizobacterial modification of plant defenses against insect herbivores: from molecular mechanisms to tritrophic interactions
Pangesti, N.P.D. - \ 2015
Wageningen University. Promotor(en): Marcel Dicke; Joop van Loon. - Wageningen : Wageningen University - ISBN 9789462572836 - 224
planten - rizosfeerbacteriën - insecten - multitrofe interacties - verdedigingsmechanismen - pseudomonas fluorescens - mamestra brassicae - pieris brassicae - plant-microbe interacties - insect-plant relaties - plant-herbivoor relaties - plants - rhizosphere bacteria - insects - multitrophic interactions - defence mechanisms - pseudomonas fluorescens - mamestra brassicae - pieris brassicae - plant-microbe interactions - insect plant relations - plant-herbivore interactions
Plants as primary producers in terrestrial ecosystems are under constant threat from a multitude of attackers, which include insect herbivores. In addition to interactions with detrimental organisms, plants host a diversity of beneficial organisms, which include microbes in the rhizosphere. Furthermore, the interactions between plants and several groups of root-associated microbes such as mycorrhizae, plant growth promoting rhizobacteria (PGPR) and plant growth promoting fungi (PGPF) can affect plant interactions with foliar insect herbivores. The beneficial root-associated microbes are able to modify plant physiology by promoting plant growth and induced systemic resistance (ISR), in which the balance between both effects will determine the final impact on the insect herbivores. Using Arabidopsis thaliana Col-0, this thesis explores the molecular mechanisms on how plants integrate responses when simultaneously interacting with the rhizobacterium Pseudomonas fluorescens and the generalist and the specialist leaf-chewing insects Mamestra brassicae and Pieris brassicae respectively.
A literature review on the state-of-the-art in the field of microbe-plant-insect interactions (Chapter 2) explores how root-associated microbes and insect folivores can influence each other via a shared host plant. For more than a decade, both ecological and mechanistic studies mostly focused on exploring these belowground and aboveground interactions using single microbe and single herbivore species. The importance of increasing the complexity of the study system in order to understand the interactions in more natural situations is being emphasized. Furthermore, this review discusses the role of plant hormones in regulating plant growth and defense against folivores, while simultaneously being involved in associations with root-associated microbes.
Experimental evidence has shown patterns on the effects of mycorrhizal colonization on plant interactions with insect herbivores, and raises the question whether plant colonization by different groups of root-associated microbes has similar effects on particular categories of insect herbivores. In Chapter 3, plant-mediated effects of a non-pathogenic rhizobacterium on the performance of leaf-chewing insects, and the underlying mechanisms modulating the interactions, have been examined. Colonization of A. thaliana Col-0 roots by the bacterium P. fluorescens strain WCS417r resulted in decreased larval weight of the generalist leaf-chewing M. brassicae, and had no effect on larval weight of the specialist leaf-chewing P. brassicae. The crucial role of jasmonic acid (JA) in regulating rhizobacteria-mediated induced systemic resistance (ISR) against M. brassicae is confirmed by including plant mutants in the study. Interestingly, I also observed that rhizobacteria can induce systemic susceptibility to M. brassicae caterpillars. Comparison of M. brassicae performance and gene transcription in A. thaliana plants, grown in potting soil or a mixture of potting soil and sand in a 1:1 ratio, shows that in a mixture of potting soil and sand, rhizobacterial treatment had a consistently negative effect on M. brassicae, whereas the effect is more variable in potting soil. Rhizobacterial treatment primed plants grown in potting soil and sand for stronger expression of JA- and ethylene-regulated genes PDF1.2 and HEL, supporting stronger resistance to M. brassicae. Taken together, the results show that soil composition can be one of the factors modulating the outcome of microbe-plant-insect interactions.
Chapter 4 further addresses the mechanisms underlying rhizobacteria-mediated ISR against the generalist leaf-chewing M. brassicae by integrating plant gene transcription, chemistry and performance of M. brassicae in wild type A. thaliana Col-0 plants and mutants defective in the JA-pathway, i.e. dde2-2 and myc2, in the ET pathway, i.e. ein2-1, and in the JA-/ET-pathway, i.e. ora59. Results of this study show that rhizobacterial colonization alone or in combination with herbivore infestation induced the expression of the defense-associated genes ORA59 and PDF1.2 at higher levels than activation by herbivore feeding alone, and the expression of both genes is suppressed in the knock-out mutant ora59. Interestingly, the colonization of plant roots by rhizobacteria alters the levels of plant defense compounds, i.e. camalexin and glucosinolates (GLS), by enhancing the synthesis of constitutive and induced levels of camalexin and aliphatic GLS while suppressing the induced levels of indole GLS. The changes are associated with modulation of the JA-/ET-signaling pathways as shown by investigating mutants. Furthermore, the herbivore performance results show that functional JA- and ET-signaling pathways are required for rhizobacteria-mediated ISR against leaf-chewing insects as observed in the knock-out mutants dde2-2 and ein2-1. The results indicate that colonization of plant roots by rhizobacteria modulates plant-insect interactions by prioritizing the ORA59-branch over the MYC2-branch, although the transcription factor ORA59 is not the only one responsible for the observed effects of rhizobacteria-mediated ISR against leaf-chewing insects.
Taking a step further in increasing the complexity of the study system, Chapter 5 investigates how co-cultivation of P. fluorescens strains WCS417r and SS101 affects direct plant defense to the caterpillar M. brassicae. Inoculation of either P. fluorescens WCS417r or SS101 singly at root tips or simultaneously at two different positions along the roots resulted in a similar level of rhizobacterial colonization by each strain, whereas co-cultivation of both strains at either the root tips or at two different positions along the roots resulted in a higher colonization level of strain WCS417r compared to colonization by SS101. The results suggest that the site of inoculation influences the direct interactions between the two strains in the rhizosphere, as also confirmed by in vitro antagonism assays in the absence of plants. Both upon single inoculation and co-cultivation of both strains at the same or different sites along the roots, the two rhizobacterial strains induced the same strength of ISR against the caterpillar M. brassicae and the same degree of plant growth promotion. In the roots, colonization by the two strains as single or mixed culture resulted in a similar gene expression pattern of up-regulation of MYC2, down-regulation of WRKY70 and no effect on NPR1 expression, genes representing JA-signaling, SA-signaling and the node of crosstalk between the two pathways, respectively. We hypothesize that both rhizobacterial strains use negative crosstalk between JA- and SA-pathways as mechanism to suppress plant immunity and establish colonization. This study shows that competitive interactions between rhizobacterial strains known to induce plant defense in systemic tissue via different signaling pathways, may interfere with synergistic effects on ISR and plant growth promotion.
While the effect of root-associated microbes on direct plant defense against insect herbivores has been studied previously, the effect of these microbes on indirect plant defense to herbivores is much less known. Chapter 6 explores how colonization by the rhizobacterium P. fluorescens strain WCS417r affects indirect plant defense against the generalist herbivore M. brassicae by combining behavioral, chemical and gene transcriptional approaches. The results show that rhizobacterial colonization of A. thaliana roots results in an increased attraction of the parasitoid Microplitis mediator to caterpillar-infested plants. Volatile analysis revealed that rhizobacterial colonization suppressed emission of the terpene (E)-α-bergamotene, and the aromatics methyl salicylate and lilial in response to caterpillar feeding. Rhizobacterial colonization decreased the caterpillar-induced transcription of the terpene synthase genes TPS03 and TPS04. Rhizobacteria enhanced both growth and indirect defense of plants under caterpillar attack. This study shows that rhizobacteria have a high potential to enhance the biocontrol of leaf-chewing herbivores based on enhanced attraction of parasitoids.
Taken together, the research presented in this thesis has shown how single or combined applications of rhizobacteria affect interactions of plants with leaf-chewing insects in terms of direct and indirect resistance. Furthermore, results presented in this thesis have revealed some of the molecular mechanisms underlying plant-mediated interactions between rhizobacteria and leaf-chewing insects that can be used in developing practical approaches by applying beneficial root-associated microbes for improving plant resistance.
|TBV kan nog laat in seizoen bollen besmetten
Dam, M.F.N. van; Stijger, C.C.M.M. ; Verbeek, M. - \ 2015
BloembollenVisie 2015 (2015)322. - ISSN 1571-5558 - p. 20 - 21.
Uit dit onderzoek is gebleken dat planten die eerder in het seizoen worden geïnfecteerd, bol len geven met een hoger percentage TBV Plan ten die eenmalig een week voor het rooien wor den besmet, geven bijna geen zieke bollen. Bij infectie twee weken en langer voor het rooien loopt het percentage zieke bollen sterk op. Ook worden klisters later ziek dan de hoofdbol. Infec tie vindt blijkbaar plaats vanuit de plant via de hoofdbol naar de klisters. ln de praktijk vindt inl'e tiegedurende hei hele seizo n pla11 door pas r nde, vliegende blad luizen. In de praktijk i du ook ni t va 1 te tel len wanneer planten voor hel er t geïnfecteerd raken. Vrijwel zeker gebeurt dat ook al vroeg in het seizoen. In dat geval is er dus geen spra ke van een lager percentage virus in de kleine maten. De resultaten hebben betrekking op het onder zoek in een cultivar ('Strong Gold') en van een seizoen (2013-2014). Om beter gefundeerde conclusies te kunnen trekken is vervolgonder zoek gestartin het seizoen 2014-2015 met twee cultivars. Het actieplan 'Minder virus in tulp' is een gezamenlijk initiatief van Wageningen UR, PPO Bloembollen, Boomkwekerij & Fruit, Proeftuin Zwaagdijk, KAVB,LTO en BKD.
Maakt de hondentrainer het verschil tussen hemel en hel voor de hond(en baas)?
Beerda, Bonne ; Borg, Joanne van der; Vellema, Sietze - \ 2014
Differential effectiveness of microbially induced resistance against herbivorous insects in Arabidopsis
Oosten, V.R. van; Bodenhausen, N. ; Reymond, Ph. ; Pelt, J.A. van; Loon, L.C. van; Dicke, M. ; Pieterse, C.M.J. - \ 2008
Molecular Plant-Microbe Interactions 21 (2008)7. - ISSN 0894-0282 - p. 919 - 930.
induced systemic resistance - lipid-transfer proteins - parasitoid cotesia-rubecula - defense signaling pathways - jasmonic acid - salicylic-acid - pseudomonas-syringae - gene-expression - plant defense - cross-talk
Rhizobacteria¿induced systemic resistance (ISR) and pathogen-induced systemic acquired resistance (SAR) have a broad, yet partly distinct, range of effectiveness against pathogenic microorganisms. Here, we investigated the effectiveness of ISR and SAR in Arabidopsis against the tissue-chewing insects Pieris rapae and Spodoptera exigua. Resistance against insects consists of direct defense, such as the production of toxins and feeding deterrents and indirect defense such as the production of plant volatiles that attract carnivorous enemies of the herbivores. Wind-tunnel experiments revealed that ISR and SAR did not affect herbivore-induced attraction of the parasitic wasp Cotesia rubecula (indirect defense). By contrast, ISR and SAR significantly reduced growth and development of the generalist herbivore S. exigua, although not that of the specialist P. rapae. This enhanced direct defense against S. exigua was associated with potentiated expression of the defense-related genes PDF1.2 and HEL. Expression profiling using a dedicated cDNA microarray revealed four additional, differentially primed genes in microbially induced S. exigua-challenged plants, three of which encode a lipid-transfer protein. Together, these results indicate that microbially induced plants are differentially primed for enhanced insect-responsive gene expression that is associated with increased direct defense against the generalist S. exigua but not against the specialist P. rapae.
|From Tropical Africa to Arctic Scandinavia: A.H.J. Prins as maritime anthropologist
Prins, H.H.T. ; Prins, H.E.L. - \ 2005
In: Het Topje van de IJsberg: 35 jaar Arctisch Centrum (1970-2005) / Boschman, N., Hacquebord, L., Veluwenkamp, J.W., Groningen : Barkhuis Publishing (Circumpolar Studies 2) - ISBN 9789077922019 - p. 21 - 29.
Dietary xylose as an energy source for young pigs.
Verstegen, M.W.A. ; Schutte, J.B. ; Hel, W. van der; Polziehn, R. ; Schrama, J.W. ; Sutton, A.L. - \ 1997
Journal of Animal Physiology and Animal Nutrition 77 (1997). - ISSN 0931-2439 - p. 180 - 188.
Effect of varying ambient temperature and porcine somatotropin treatment in pigs on feed intake and energy balance traits
Hel, W. van der; Verstegen, M.W.A. ; Schrama, J.W. ; Brandsma, H.A. ; Sutton, A.L. - \ 1997
Livestock Production Science 51 (1997). - ISSN 0301-6226 - p. 21 - 28.
|Optimal temperature levels for racing pigeons (Columbia livia) housed under transport conditions: the role of water availability and age.
Gorssen, J. ; Schrama, J.W. ; Hel, W. van der; Noordhuizen, J.P.T.M. ; Linden, J.M. van der - \ 1997
Vlaams Diergeneeskundig Tijdschrift 66 (1997). - ISSN 0303-9021 - p. 81 - 87.
diergeneeskunde - duiven - veevervoer - lichaamstemperatuur - thermoregulatie - regulatie van de lichaamstemperatuur - wedstrijddieren - jagen - werkdieren - drinken - drinkwater - veterinary science - pigeons - transport of animals - body temperature - thermoregulation - body temperature regulation - racing animals - hunting - working animals - drinking - drinking water
Gegevens van onderzoek over het optimale temperatuurniveau van reisduiven tijdens transport
|The effect of Trypanosoma vivax infection on energy and nitrogen metabolism, and serum metabolites and hormones in West African Dwarf Goats at different feed intake levels.
Dam, J.T.P. van; Heide, D. van der; Hel, W. van der; Ingh, J.S.G.A.M. van den; Verstegen, M.W.A. ; Wensing, T. ; Zwart, D. - \ 1996
Animal Science 63 (1996)1. - ISSN 1357-7298 - p. 111 - 121.
Required thermal thresholds during transport of animals.
Schrama, J.W. ; Hel, W. van der; Gorssen, J. ; Henken, A.M. ; Verstegen, M.W.A. ; Noordhuizen, J.P.T.M. - \ 1996
Veterinary Quarterly 18 (1996). - ISSN 0165-2176 - p. 90 - 95.
Heat production, body temperature, and body posture in West African Dwarf goats infected with Trypanosoma vivax.
Dam, J.T.P. van; Schrama, J.W. ; Hel, W. van der; Verstegen, M.W.A. ; Zwart, D. - \ 1996
Veterinary Quarterly 18 (1996). - ISSN 0165-2176 - p. 55 - 59.
|Effects of atrophic rhinitis and climatic environment on the performance of GY-pigs.
Diemen, P.M. van; Schrama, J.W. ; Hel, W. van der; Verstegen, M.W.A. ; Noordhuizen, J.P.T.M. - \ 1995
Livestock Production Science 43 (1995). - ISSN 0301-6226 - p. 275 - 284.
Development metabolic partitioning of energy in young calves
Arieli, A. ; Schrama, J.W. ; Hel, W. van der; Verstegen, M.W.A. - \ 1995
Journal of Dairy Science 78 (1995). - ISSN 0022-0302 - p. 1154 - 1162.
Modifications in thermal demand and energy partitioning in newborn calves were determined over time via indirect calorimetry. One-week-old calves were fed milk replacer at 70 and 110% of the metabolizable energy requirements for maintenance, at ambient temperatures of 7.5 or 19°C, over two consecutive but separately monitored 7-d balance periods. During wk l, N digestibility, energy digestibility, and energy metabolizability were lower than during wk 2. Heat production decreased, but retention of energy and fat increased, between balance periods. During wk l, initial IgG concentration in serum was positively correlated with digestibilities of N and energy, and hemoglobin concentration was negatively correlated with heat production. Regression analysis revealed that predicted basal metabolic rate, efficiency of metabolizable energy use, and metabolizable energy requirements for maintenance were lower for wk 2 than for wk 1. Decreased energy utilization in calves on restricted feedings is related to an increase in the utilization of protein as an energy source. Young calves need at least 2 wk to adapt to the combination of new environmental temperature and low feeding amount. Metabolic partitioning of energy may indicate completion of the adaptation stage.
Effect of recombinant porcine somatotropin and monoclonal antibody directed to ovine somatotrophic hormone on nitrogen retention and immune parameters in pigs.
Hel, W. van der; Parmentier, H.K. ; Hole, N.J.K. ; James, S. ; Brandsma, H.A. ; Fentener van Vlissingen, J.M. ; Nieuwland, M.G.B. ; Joling, P. - \ 1994
Journal of Animal Science 72 (1994). - ISSN 0021-8812 - p. 2820 - 2827.
|Intranasal administration of Pasteurella multocida toxin in a challenge-exposure model used to induce subclinical signs of atrophic rhinitis in pigs.
Diemen, P.M. van; Jong, M.F. de; Vries Reilingh, G. de; Hel, W. van der; Schrama, J.W. - \ 1994
American Journal of Veterinary Research 55 (1994). - ISSN 0002-9645 - p. 49 - 54.
|Transport of farm animals: the thermal environment.
Schrama, J.W. ; Hel, W. van der; Henken, A.M. ; Gorssen, J. ; Verstegen, M.W.A. - \ 1994
In: Proc. 40th Int. Congr. Meat Science and Technology, Den Haag - p. 85 - 96.
|Klimaatbehoeften van postduiven tijdens transport, fase I.
Gorssen, J. ; Hel, W. van der - \ 1994
Unknown Publisher - 72 p.
|Circadian rhythm in heat production of limit fed growing pigs of several breeds kept at and below thermal neutrality.
Henken, A.M. ; Brandsma, A.M. ; Hel, W. van der; Verstegen, M.W.A. - \ 1993
Journal of Animal Science 71 (1993). - ISSN 0021-8812 - p. 1434 - 1440.