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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Harnessing a 'currency matrix' for performance measurement in cooperatives : A multi-phased study
Benos, Theo ; Kalogeras, Nikos ; Wetzels, Martin ; Ruyter, Ko de; Pennings, Joost M.E. - \ 2018
Sustainability 10 (2018)12. - ISSN 2071-1050
Cooperatives - Delphi method - Extensive review - Interdisciplinary dialogue - Performance measurement - Social enterprises - Socio-economic impact

The cooperative organizational form is by nature a sustainable one, which has proved to be resilient in the face of crises and a solid lever in addressing present-day societal challenges. Still, little is known about its socio-economic impact. Also, despite the plethora of studies on cooperative performance, research remains inconclusive about how to best measure it. In fact, scholarly work has largely favored the use of appraisal tools reflecting those of investor-owned firms (IOFs), having undermined the dual idiosyncratic nature of the cooperative organizational form, which is manifest in the business and social-membership objectives. The goal of this article is to fill these gaps by delivering a comprehensive dashboard for cooperative performance assessment that harmonizes business-social aspects and catalogs the basic components for future attempts. To reach this goal, we used an extensive review of empirical research in cooperative performance (phase 1) and a Delphi study with 14 experts (phase 2). In addition, we reviewed comparable research efforts for a business form (social enterprises) that combines business with social goals and faces similar challenges (phase 3). This inquiry was particularly insightful for the social perspective and the overlooked role of cooperatives as a socially-embedded organizational form that hardly documents its societal impact and outreach.

Agrobacterium rhizogenes transformed calli of the holoparasitic plant Phelipanche ramosa maintain parasitic competence
Libiaková, Dagmara ; Ruyter-Spira, Carolien ; Bouwmeester, Harro J. ; Matusova, Radoslava - \ 2018
Plant Cell, Tissue and Organ Culture: an international journal on in vitro culture of higher plants 135 (2018)2. - ISSN 0167-6857 - p. 321 - 329.
Genetic transformation - Holoparasitic plant - In vitro - Phelipanche ramosa - Regeneration
Phelipanche and Orobanche spp. (broomrapes) are economically important parasitic weeds, causing severe damage to many agricultural crops. However, conventional methods to control these parasitic weeds are often not effective. Targeting molecular and biochemical processes involved in the establishment of the connection between the parasite and the host may offer a new perspective for control. However, progress in the understanding of these processes is hampered by the fact that genetic transformation and regeneration of these parasites is difficult if not impossible due to their specific lifecycle. Phelipanche and Orobanche spp. are holoparasites that need to attach to the roots of a host plant to get their assimilates, nutrients and water to develop and reproduce. The present study describes a highly efficient genetic transformation and regeneration protocol for the root holoparasitic Phelipanche ramosa. We present a new transformation system for P. ramosa using Agrobacterium rhizogenes MSU440 carrying a non-destructive selection marker gene coding for a red fluorescent protein (DsRed1). Using this protocol up to 90% transformation efficiency was obtained. We transformed 4 weeks old P. ramosa calli and transgenic calli expressing DsRed1 were then cultured on host plants. For the first time, we present shoot and flower development of the transgenic parasitic plant P. ramosa after successful connection of transgenic calli with the host plant roots. Moreover, we also present, for the first time, growth and development of P. ramosa shoots and flowers in vitro in the absence of a host plant.
Diagnosing member-customer ostracism in co-operatives and counterpoising its relationship-poisoning effects
Benos, Theo ; Kalogeras, Nikos ; Ruyter, Ko de; Wetzels, Martin - \ 2018
European Journal of Marketing 52 (2018)9/10. - ISSN 0309-0566 - p. 1778 - 1801.
Co-operatives - Coping strategy - Membership - Ostracism - Relationship marketing - Relationship poison

Purpose: This paper aims to examine a core member-customer threat in co-operatives (co-ops) by drawing from ostracism research, assessing co-op ostracism’s impact on critical membership and relational exchange outcomes and discussing why relationship marketing research needs to pay more attention to the overlooked role of implicit mistreatment forms in customer harm-doing. Design/methodology/approach: Three studies were conducted. In Study 1, ostracism in co-ops was explored, and a measurement scale for co-op ostracism was developed. In Study 2, the core conceptual model was empirically tested with data from members of three different co-ops. In Study 3, a coping strategy was integrated into an extended model and empirically tested with a new sample of co-op members. Findings: Ostracism is present in co-ops and “poisons” crucial relational (and membership) outcomes, despite the presence of other relationship-building or relationship-destroying accounts. Coupling entitativity with cognitive capital attenuates ostracism’s impact. Research limitations/implications: Inspired by co-ops’ membership model and inherent relational advantage, this research is the first to adopt a co-op member-customer perspective and shed light on an implicit relationship-destroying factor. Practical implications: Co-op decision makers might use the diagnostic tool developed in the paper to detect ostracism and fight it. Moreover, a novel coping strategy for how co-ops (or other firms) might fend off ostracism threats is offered in the article. Originality/value: The present study illuminates a dark side of a relationally profuse customer context, painting a more complete picture of relationship marketing determinants. Little attention has been given to ostracism as a distinct and important social behaviour in marketing research and to co-ops as a research context.

The tomato MAX1 homolog, SlMAX1, is involved in the biosynthesis of tomato strigolactones from carlactone
Zhang, Yanxia ; Cheng, Xi ; Wang, Yanting ; Díez-Simón, Carmen ; Flokova, Kristyna ; Bimbo, Andrea ; Bouwmeester, Harro J. ; Ruyter-Spira, Carolien - \ 2018
New Phytologist 219 (2018)1. - ISSN 0028-646X - p. 297 - 309.
cytochrome P450 (CYP) - didehydro-orobanchol isomers - MORE AXILLARY GROWTH 1 (MAX1) - orobanchol - solanacol - tomato strigolactones
Strigolactones (SLs) are rhizosphere signalling molecules exuded by plants that induce seed germination of root parasitic weeds and hyphal branching of arbuscular mycorrhiza. They are also phytohormones regulating plant architecture. MORE AXILLARY GROWTH 1 (MAX1) and its homologs encode cytochrome P450 (CYP) enzymes that catalyse the conversion of the strigolactone precursor carlactone to canonical strigolactones in rice (Oryza sativa), and to an SL-like compound in Arabidopsis. Here, we characterized the tomato (Solanum lycopersicum) MAX1 homolog, SlMAX1. The targeting induced local lesions in genomes method was used to obtain Slmax1 mutants that exhibit strongly reduced production of orobanchol, solanacol and didehydro-orobanchol (DDH) isomers. This results in a severe strigolactone mutant phenotype in vegetative and reproductive development. Transient expression of SlMAX1 – together with SlD27, SlCCD7 and SlCCD8 – in Nicotiana benthamiana showed that SlMAX1 catalyses the formation of carlactonoic acid from carlactone. Plant feeding assays showed that carlactone, but not 4-deoxy-orobanchol, is the precursor of orobanchol, which in turn is the precursor of solanacol and two of the three DDH isomers. Inhibitor studies suggest that a 2-oxoglutarate-dependent dioxygenase is involved in orobanchol biosynthesis from carlactone and that the formation of solanacol and DDH isomers from orobanchol is catalysed by CYPs.
Weerbaarder, guller en attractiever : naar een nieuwe aanpak voor het veen in het Lage Midden van Fryslân
Ruyter, P. de; Vogelzang, T.A. ; Prins, H. - \ 2018
- 32 p.
Zeapyranolactone − A novel strigolactone from maize
Charnikhova, Tatsiana V. ; Gaus, Katharina ; Lumbroso, Alexandre ; Sanders, Mark ; Vincken, Jean Paul ; Mesmaeker, Alain De; Ruyter-Spira, Carolien P. ; Screpanti, Claudio ; Bouwmeester, Harro J. - \ 2018
Phytochemistry letters 24 (2018). - ISSN 1874-3900 - p. 172 - 178.
Maize (Zea mays) - NMR - Prep-HPLC–MS - Strigolactones - Zeapyranolactone
The structure of a new strigolactone present in the root exudate and root extract of maize hybrid cv NK Falkone plants was elucidated and characterized as zeapyranolactone: Methyl.(E)-3-((4-methyl-5-oxo-2,5-dihydrofuran-2-yl)oxy)-2-(4,4,5-trimethyl-2-oxo-2,3,4,6,7,7a-hexahydrocyclopenta[b]pyran-7-yl)acrylate. Unlike any other strigolactone published so far, it contains a 4,4-dimethyltetrahydropyran-2-one as A ring. The impact of the elucidation of this structure on the earlier postulated biosynthetic pathway of another maize strigolactone, zealactone, is discussed.
Blockchain for agriculture and food : Findings from the pilot study
Ge, Lan ; Brewster, Christopher ; Spek, Jacco ; Smeenk, Anton ; Top, Jan ; Diepen, Frans van; Klaase, Bob ; Graumans, Conny ; Ruyter de Wildt, Marieke de - \ 2017
Wageningen : Wageningen Economic Research (Wageningen Economic Research report 2017-112) - ISBN 9789463438179 - 33
This report documents experiences and findings from the public private partnership (PPP) project ‘Blockchain for Agrifood’ that was started in March 2017. The project aims to contribute to a better understanding of the blockchain technology (BCT) and its implications for agrifood, especially how it can impact specific aspects of supply chains and what is needed to apply BCT in agrifood chains. A second aim of this project is to conceptualise and develop a proof of concept in an application based on a use case concerning table grapes from South Africa where BCT could be applied. This has been done by building a demonstrator that keeps track of different certificates involved in the table grapes supply chain. The code of this demonstrator is published at Github. Furthermore, the project explored issues regarding the relevance, applicability and implications of BCT for the agrifood sector through literature study and stakeholder consultation.
Exploring the resistance against root parasitic plants in Arabidopsis and tomato
Cheng, Xi - \ 2017
University. Promotor(en): H.J. Bouwmeester, co-promotor(en): Carolien Ruyter-Spira. - Wageningen : Wageningen University - ISBN 9789463437004 - 305
plants - parasitic plants - arabidopsis thaliana - solanum lycopersicum - host parasite relationships - plant growth regulators - resistance - planten - parasitaire planten - gastheer parasiet relaties - plantengroeiregulatoren - weerstand
Root parasitic plant species such as broomrapes (Orobanche and Phelipanche spp.) and witchweeds (Striga spp.) are notorious agricultural weeds. They cause damage to crops by depriving them of water, nutrients and assimilates via a vascular connection. The difficulty in controlling root parasitic weeds is largely due to their intricate lifecycle and partially underground lifestyle. Their life cycle includes processes such as germination of the seed, the formation of the vascular connection with the host, the growth and development of the parasite after attachment and the emergence of shoots and flowers aboveground. The germination of many parasitic plants is induced by strigolactones that were recently shown to also be signalling compounds that stimulate mycorrhizal symbiosis. In addition, in the past few years, their role in plant development and plant defense has been established revealing them as a new class of plant hormones that exert their function likely in interaction with other hormones.
The role of strigolactones and the fungal microbiome in rice during drought adaptation
Andreo Jimenez, Beatriz - \ 2017
University. Promotor(en): Harro Bouwmeester, co-promotor(en): Carolien Ruyter-Spira. - Wageningen : Wageningen University - ISBN 9789463437028 - 205
drought resistance - drought - abiotic injuries - rice - oryza sativa - plant-microbe interactions - nutrient uptake - defence mechanisms - hormones - fungi - genes - droogteresistentie - droogte - abiotische beschadigingen - rijst - plant-microbe interacties - voedingsstoffenopname (planten) - verdedigingsmechanismen - hormonen - schimmels - genen

Rice is the most important food crop in the world, feeding over half the world’s population. However, rice water use efficiency, defined by units of yield produced per unit of water used, is the lowest of all crops. The aim of this thesis was to study the effect of plant hormones and the root microbiome on drought tolerance in rice. The new plant hormone, strigolactone, was shown to be upregulated under drought and to regulate drought tolerance in interaction with the drought-hormone abscisic acid. Using a large collection of rice genotypes grown in the field, we showed that the composition of the root associated fungal microbiome is determined by the rice genotype and can contribute to drought tolerance.

Mutation in sorghum LOW GERMINATION STIMULANT 1 alters strigolactones and causes Striga resistance
Gobena, Daniel ; Shimels, Mahdere ; Rich, Patrick J. ; Ruyter-Spira, Carolien ; Bouwmeester, Harro ; Kanuganti, Satish ; Mengiste, Tesfaye ; Ejeta, Gebisa - \ 2017
Proceedings of the National Academy of Sciences of the United States of America 114 (2017)17. - ISSN 0027-8424 - p. 4471 - 4476.
Gene - Sorghum - Stereochemistry - Striga - Strigolactone

Striga is a major biotic constraint to sorghum production in semiarid tropical Africa and Asia. Genetic resistance to this parasitic weed is the most economically feasible control measure. Mutant alleles at the LGS1 (LOW GERMINATION STIMULANT 1) locus drastically reduce Striga germination stimulant activity. We provide evidence that the responsible gene at LGS1 codes for an enzyme annotated as a sulfotransferase and show that functional loss of this gene results in a change of the dominant strigolactone (SL) in root exudates from 5-deoxystrigol, a highly active Striga germination stimulant, to orobanchol, an SL with opposite stereochemistry. Orobanchol, although not previously reported in sorghum, functions in the multiple SL roles required for normal growth and environmental responsiveness but does not stimulate germination of Striga. This work describes the identification of a gene regulating Striga resistance and the underlying protective chemistry resulting from mutation.

The role of endogenous strigolactones and their interaction with ABA during the infection process of the parasitic weed Phelipanche ramosa in tomato plants
Cheng, Xi ; Floková, Kristýna ; Bouwmeester, Harro ; Ruyter-Spira, Carolien - \ 2017
Frontiers in Plant Science 8 (2017). - ISSN 1664-462X
Abscisic acid - Plant architecture - Post-attachment resistance - Root parasitic plant - Strigolactone
The root parasitic plant species Phelipanche ramosa, branched broomrape, causes severe damage to economically important crops such as tomato. Its seed germination is triggered by host-derived signals upon which it invades the host root. In tomato, strigolactones (SLs) are the main germination stimulants for P. ramosa. Therefore, the development of low SL-producing lines may be an approach to combat the parasitic weed problem. However, since SLs are also a plant hormone controlling many aspects of plant development, SL deficiency may also have an effect on post-germination stages of the infection process, during the parasite-host interaction. In this study, we show that SL-deficient tomato plants (Solanum lycopersicum; SlCCD8 RNAi lines), infected with pre-germinated P. ramosa seeds, display an increased infection level and faster development of the parasite, which suggests a positive role for SLs in the host defense against parasitic plant invasion. Furthermore, we show that SL-deficient tomato plants lose their characteristic SL-deficient phenotype during an infection with P. ramosa through a reduction in the number of internodes and the number and length of secondary branches. Infection with P. ramosa resulted in increased levels of abscisic acid (ABA) in the leaves and roots of both wild type and SL-deficient lines. Upon parasite infection, the level of the conjugate ABA-glucose ester (ABA-GE) also increased in leaves of both wild type and SL-deficient lines and in roots of one SL-deficient line. The uninfected SL-deficient lines had a higher leaf ABA-GE level than the wild type. Despite the high levels of ABA, stomatal aperture and water loss rate were not affected by parasite infection in the SL-deficient line, while in wild type tomato stomatal aperture and water loss increased upon infection. Future studies are needed to further underpin the role that SLs play in the interaction of hosts with parasitic plants and which other plant hormones interact with the SLs during this process.
Vechten tegen rijstvampiers : parasitaire planten bedreigen voedselzekerheid in Afrika
Bastiaans, Lammert ; Tippe, Dennis ; Ruyter-Spira, Carolien - \ 2017

Verwoestende parasitaire onkruiden richten voor miljoenen schade aan in de gewassen ten zuiden van de Sahara. Ze zuigen hun waardplanten uit als vampiers. Onderzoekers proberen deze ondergrondse profiteurs te dwarsbomen.

Zealactones. Novel natural strigolactones from maize
Charnikhova, Tatsiana V. ; Gaus, Katharina ; Lumbroso, Alexandre ; Sanders, Mark ; Vincken, Jean Paul ; Mesmaeker, Alain de; Ruyter-Spira, Carolien P. ; Screpanti, Claudio ; Bouwmeester, Harro J. - \ 2017
Phytochemistry 137 (2017). - ISSN 0031-9422 - p. 123 - 131.
Maize (Zea mays) - NMR - Prep-HPLC-MS - Seed germination - Striga hermonthica (Orobanchaceae) - Strigolactones - UHPLC-MS-MS - Zealactone

In the root exudate and root extracts of maize hybrid cv NK Falkone seven putative strigolactones were detected using UPLC-TQ-MS-MS. All seven compounds displayed MS-MS-fragmentation common for strigolactones and particularly the presence of a fragment of m/z 97 Da, which may indicate the presence of the so-called D-ring, suggests they are strigolactones. The levels of all these putative strigolactones increased upon phosphate starvation and decreased upon fluridone (carotenoid biosynthesis inhibitor) treatment, both of which are a common response for strigolactones. All seven compounds were subsequently isolated with prep-HPLC-MS. They all exhibited Striga hermonthica seed germination inducing activity just as the synthetic strigolactone analog GR24. The structure of two of the seven compounds was elucidated by NMR spectroscopy as: methyl (2E,. 3E)-4-(3,. 3-dimethyl-5-oxo-2-(prop-1-en-2-yl)tetrahydrofuran-2-yl)-2-(((4-methyl-5-oxo-2,. 5-dihydrofuran-2-yl)oxy)methylene)but-3-enoate (two diastereomers 1a and 1b). Strigolactones (1a/b) are closely related to the methyl ester of carlactonoic acid (MeCLA) and heliolactone. However, they contain a unique 4,4-dimethyltetrahydrofuran-2-one motif as the "A-ring" instead of the classical (di)methylcyclohexene. Because these compounds were isolated from maize (Zea mays) we called them "zealactone 1a and 1b". The implications of this discovery for our view on strigolactones and their biosynthesis are discussed.

Genetic architecture of plant stress resistance: multi-trait genome-wide association mapping
Thoen, H.P.M. ; Davila Olivas, N.H. ; Kloth, K.J. ; Coolen, Silvia ; Huang, P. ; Aarts, M.G.M. ; Molenaar, J.A. ; Bakker, J. ; Bouwmeester, H.J. ; Broekgaarden, C. ; Bucher, J. ; Busscher-Lange, J. ; Cheng, X. ; Dijk-Fradin, E.F. van; Jongsma, M.A. ; Julkowska, Magdalena M. ; Keurentjes, J.J.B. ; Ligterink, W. ; Pieterse, Corné M.J. ; Ruyter-Spira, C.P. ; Smant, G. ; Schaik, C.C. van; Wees, Saskia C.M. van; Visser, R.G.F. ; Voorrips, R.E. ; Vosman, B. ; Vreugdenhil, D. ; Warmerdam, S. ; Wiegers, G.L. ; Heerwaarden, J. van; Kruijer, W.T. ; Eeuwijk, F.A. van; Dicke, M. - \ 2017
New Phytologist 213 (2017)3. - ISSN 0028-646X - p. 1346 - 1362.
Plants are exposed to combinations of various biotic and abiotic stresses, but stress responses are usually investigated for single stresses only. Here, we investigated the genetic architecture underlying plant responses to 11 single stresses and several of their combinations by phenotyping 350 Arabidopsis thaliana accessions. A set of 214 000 single nucleotide polymorphisms (SNPs) was screened for marker-trait associations in genome-wide association (GWA) analyses using tailored multi-trait mixed models. Stress responses that share phytohormonal signaling pathways also share genetic architecture underlying these responses. After removing the effects of general robustness, for the 30 most significant SNPs, average quantitative trait locus (QTL) effect sizes were larger for dual stresses than for single stresses. Plants appear to deploy broad-spectrum defensive mechanisms influencing multiple traits in response to combined stresses. Association analyses identified QTLs with contrasting and with similar responses to biotic vs abiotic stresses, and below-ground vs above-ground stresses. Our approach allowed for an unprecedented comprehensive genetic analysis of how plants deal with a wide spectrum of stress conditions.
Low levels of strigolactones in roots as a component of the systemic signal of drought stress in tomato
Visentin, Ivan ; Vitali, Marco ; Ferrero, Manuela ; Zhang, Yanxia ; Ruyter-Spira, Carolien ; Novák, Ondřej ; Strnad, Miroslav ; Lovisolo, Claudio ; Schubert, Andrea ; Cardinale, Francesca - \ 2016
New Phytologist 212 (2016)4. - ISSN 0028-646X - p. 954 - 963.
Abscisic acid (ABA) - Drought - Strigolactones (SL) - Systemic signalling - Tomato (Solanum lycopersicum)

Strigolactones (SL) contribute to drought acclimatization in shoots, because SL-depleted plants are hypersensitive to drought due to stomatal hyposensitivity to abscisic acid (ABA). However, under drought, SL biosynthesis is repressed in roots, suggesting organ specificity in their metabolism and role. Because SL can be transported acropetally, such a drop may also affect shoots, as a systemic indication of stress. We investigated this hypothesis by analysing molecularly and physiologically wild-type (WT) tomato (Solanum lycopersicum) scions grafted onto SL-depleted rootstocks, compared with self-grafted WT and SL-depleted genotypes, during a drought time-course. Shoots receiving few SL from the roots behaved as if under mild stress even if irrigated. Their stomata were hypersensitive to ABA (likely via a localized enhancement of SL synthesis in shoots). Exogenous SL also enhanced stomata sensitivity to ABA. As the partial shift of SL synthesis from roots to shoots mimics what happens under drought, a reduction of root-produced SL might represent a systemic signal unlinked from shootward ABA translocation, and sufficient to prime the plant for better stress avoidance.

Arbuscular mycorrhizal symbiosis induces strigolactone biosynthesis under drought and improves drought tolerance in lettuce and tomato
Ruiz-Lozano, J.M. ; Aroca, R. ; Zamarreno, A.M. ; Molina, S. ; Andreo Jimenez, B. ; Porcel, R. ; Garcia-Mina, J.M. ; Ruyter-Spira, C.P. ; Lopez-Raez, J.A. - \ 2016
Plant, Cell & Environment 39 (2016)2. - ISSN 0140-7791 - p. 441 - 452.
Arbuscular mycorrhizal (AM) symbiosis alleviates drought stress in plants. However, the intimate mechanisms involved, as well as its effect on the production of signalling molecules associated with the host plant–AM fungus interaction remains largely unknown. In the present work, the effects of drought on lettuce and tomato plant performance and hormone levels were investigated in non-AM and AM plants. Three different water regimes were applied, and their effects were analysed over time. AMplants showed an improved growth rate and efficiency of photosystem II than non-AM plants under drought from very early stages of plant colonization. The levels of the phytohormone abscisic acid, as well as the expression of the correspondingmarker genes, were influenced by drought stress in non-AMandAMplants. The levels of strigolactones and the expression of corresponding marker genes were affected by both AM symbiosis and drought. The results suggest that AM symbiosis alleviates drought stress by altering the hormonal profiles and affecting plant physiology in the host plant. In addition, a correlation between AM root colonization, strigolactone levels and drought severity is shown, suggesting that under these unfavourable conditions, plants might increase strigolactone production in order to promote symbiosis establishment to cope with the stress.
Osmotic stress represses strigolactone biosynthesis in Lotus japonicus roots: exploring the interaction between strigolactones and ABA under abiotic stress
Liu, J. ; He, H. ; Vitali, M. ; Visentin, I. ; Charnikhova, T. ; Haider, I. ; Schubert, A. ; Ruyter-Spira, C.P. - \ 2015
Planta 241 (2015)6. - ISSN 0032-0935 - p. 1435 - 1451.
Main conclusion Strigolactone changes and cross talk with ABA unveil a picture of root-specific hormonal dynamics under stress. Abstract Strigolactones (SLs) are carotenoid-derived hormones influencing diverse aspects of development and communication with (micro)organisms, and proposed as mediators of environmental stimuli in resource allocation processes; to contribute to adaptive adjustments, therefore, their pathway must be responsive to environmental cues. To investigate the relationship between SLs and abiotic stress in Lotus japonicus, we compared wild-type and SLdepleted plants, and studied SL metabolism in roots stressed osmotically and/or phosphate starved. SL-depleted plants showed increased stomatal conductance, both under normal and stress conditions, and impaired resistance to drought associated with slower stomatal closure in response to abscisic acid (ABA). This confirms that SLs contribute to drought resistance in species other than Arabidopsis. However, we also observed that osmotic stress rapidly and strongly decreased SL concentration in tissues and exudates of wild-type Lotus roots, by acting on the transcription of biosynthetic and transporter-encoding genes and independently of phosphate abundance. Pretreatment with exogenous SLs inhibited the osmotic stressinduced ABA increase in wild-type roots and downregulated the transcription of the ABA biosynthetic gene
Engineering the plant rhizosphere
Zhang, Y. ; Ruyter-Spira, C.P. ; Bouwmeester, H.J. - \ 2015
Current Opinion in Biotechnology 32 (2015). - ISSN 0958-1669 - p. 136 - 142.
Plant natural products are low molecular weight compounds playing important roles in plant survival under biotic and abiotic stresses. In the rhizosphere, several groups of plant natural products function as semiochemicals that mediate the interactions of plants with other plants, animals and microorganisms. The knowledge on the biosynthesis and transport of these signaling molecules is increasing fast. This enables us to consider to optimize plant performance by changing the production of these signaling molecules or their exudation into the rhizosphere. Here we discuss recent advances in the understanding and metabolic engineering of these rhizosphere semiochemicals.
Ecological relevance of strigolactones in nutrient uptake and other abiotic stresses, and in plant-microbe interactions below ground
Andreo Jimenez, B. ; Ruyter-Spira, C.P. ; Bouwmeester, H.J. ; Lopez-Raez, J.A. - \ 2015
Plant and Soil 394 (2015)1. - ISSN 0032-079X - p. 1 - 19.
arbuscular mycorrhizal fungi - carotenoid cleavage dioxygenases - root-system architecture - phosphate starvation - medicago-truncatula - drought stress - abscisic-acid - analog gr24 - stomatal conductance - rhizobial infection
Background Plants are exposed to ever changing and often unfavourable environmental conditions, which cause both abiotic and biotic stresses. They have evolved sophisticated mechanisms to flexibly adapt themselves to these stress conditions. To achieve such adaptation, they need to control and coordinate physiological, developmental and defence responses. These responses are regulated through a complex network of interconnected signalling pathways, in which plant hormones play a key role. Strigolactones (SLs) are multifunctional molecules recently classified as a new class of phytohormones, playing a key role as modulators of the coordinated plant development in response to nutrient deficient conditions, especially phosphorus shortage. Belowground, besides regulating root architecture, they also act as molecular cues that help plants to communicate with their environment. Scope This review discusses current knowledge on the different roles of SLs below-ground, paying special attention to their involvement in phosphorus uptake by the plant by regulating root architecture and the establishment of mutualistic symbiosis with arbuscular mycorrhizal fungi. Their involvement in plant responses to other abiotic stresses such as drought and salinity, as well as in other plant-(micro)organisms interactions such as nodulation and root parasitic plants are also highlighted. Finally, the agronomical implications of SLs below-ground and their potential use in sustainable agriculture are addressed. Conclusions Experimental evidence illustrates the biological and ecological importance of SLs in the rhizosphere. Their multifunctional nature opens up a wide range of possibilities for potential applications in agriculture. However, a more in-depth understanding on the SL functioning/signalling mechanisms is required to allow us to exploit their full potential.
Slimme Winkelwagens: Hoe Realtime Bestedingsfeedback het Winkelgedrag Beinvloedt
Ittersum, K. van; Wansink, B. ; Pennings, J.M.E. ; Sheeman, D. - \ 2015
In: Jaarboek MarktOnderzoekAssociatie : Ontwikkelingen in het Marktonderzoek / Bronner, A.E., Dekker, P., de Leeuw, E., Paas, L.J., de Ruyter, K., Smidts, A., Wieringa, J.E., - p. 95 - 107.
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