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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Soil Salinity Limits Plant Shade Avoidance
Hayes, Scott ; Pantazopoulou, Chrysoula K. ; Gelderen, Kasper van; Reinen, Emilie ; Tween, Adrian Louis ; Sharma, Ashutosh ; Vries, Michel de; Prat, Salomé ; Schuurink, Robert C. ; Testerink, Christa ; Pierik, Ronald - \ 2019
Current Biology 29 (2019)10. - ISSN 0960-9822 - p. 1669 - 1676.e4.
abscisic acid - brassinosteroids - phytochrome - phytohormones - PIF - plant photobiology - salt response - salt stress

Global food production is set to keep increasing despite a predicted decrease in total arable land [1]. To achieve higher production, denser planting will be required on increasingly degraded soils. When grown in dense stands, crops elongate and raise their leaves in an effort to reach sunlight, a process termed shade avoidance [2]. Shade is perceived by a reduction in the ratio of red (R) to far-red (FR) light and results in the stabilization of a class of transcription factors known as PHYTOCHROME INTERACTING FACTORS (PIFs) [3, 4]. PIFs activate the expression of auxin biosynthesis genes [4, 5] and enhance auxin sensitivity [6], which promotes cell-wall loosening and drives elongation growth. Despite our molecular understanding of shade-induced growth, little is known about how this developmental program is integrated with other environmental factors. Here, we demonstrate that low levels of NaCl in soil strongly impair the ability of plants to respond to shade. This block is dependent upon abscisic acid (ABA) signaling and the canonical ABA signaling pathway. Low R:FR light enhances brassinosteroid (BR) signaling through BRASSINOSTEROID SIGNALING KINASE 5 (BSK5) and leads to the activation of BRI1 EMS SUPPRESSOR 1 (BES1). ABA inhibits BSK5 upregulation and interferes with GSK3-like kinase inactivation by the BR pathway, thus leading to a suppression of BES1:PIF function. By demonstrating a link between light, ABA-, and BR-signaling pathways, this study provides an important step forward in our understanding of how multiple environmental cues are integrated into plant development. Intensively farmed crops often experience multiple stresses simultaneously. Here, Hayes et al. show that low-level soil salinity suppresses shade avoidance in plants. Through investigation of the mechanisms underlying this trait, they uncover a regulatory pathway that converges at the level of brassinosteroid signaling.

Seminal plasma amino acid profile in different breeds of chicken : Role of seminal plasma on sperm cryoresistance
Santiago-Moreno, Julián ; Bernal, Berenice ; Pérez-Cerezales, Serafín ; Castaño, Cristina ; Toledano-Díaz, Adolfo ; Esteso, Milagros C. ; Gutiérrez-Adán, Alfonso ; López-Sebastián, Antonio ; Gil, María G. ; Woelders, Henri ; Blesbois, Elisabeth - \ 2019
PLoS ONE 14 (2019)1. - ISSN 1932-6203

Seminal plasma is a key biological fluid that modulates sperm function in the reproduction process. However, its role in sperm biotechnologies is scarce in poultry. The aims of the present study were to study the amino acids profile and total proteins of seminal plasma in 12 Spanish chicken breeds and to investigate the role of seminal plasma on cryoresistance of rooster sperm. To investigate the role of seminal plasma on cryoresistance, diluted pooled semen samples were cryopreserved in the presence and absence of seminal plasma. Glutamic acid was the most abundant free amino acid in seminal plasma, followed by alanine, serine, valine, and glycine. There was an influence of breed (P<0.05) on the percentage of viable sperm after freezing-thawing of samples with seminal plasma. Cluster analysis revealed that White Prat, Black Castellana, Blue Andaluza, Quail Castellana, and Red-Barred Vasca returned the best freezing-thawing response (good freezers). There was a positive correlation between seminal plasma concentrations of valine, isoleucine lysine, leucine and post thaw viability. The evaluation of fertilization capacity of frozen-thawed semen from the breeds White Prat (‘good freezer’) and Black-Red Andaluza (‘bad freezer’) showed that good freezer had higher fertility (20/68, 29.4%) compared to bad freezer breed (14/76, 18.4%), even if the difference was not significant (P = 0.08). The TUNEL assay revealed that freezing/thawing procedures in presence of seminal plasma provoked higher DNA fragmentation in most of the breeds, with a positive correlation between seminal alanine, valine, isoleucine, methionine, leucine, tyrosine, phenylalanine concentrations and DNA integrity. DNA fragmentation was lower in absence of seminal plasma and the breed effect on sperm viability was highly reduced. It is concluded that specific seminal plasma amino acids were associated with post-thaw percentage of viable sperm and DNA integrity. The removal of seminal plasma decreases the variability of the results and DNA fragmentation damages.

Potato StCONSTANS-like1 Suppresses Storage Organ Formation by Directly Activating the FT-like StSP5G Repressor
Abelenda, José A. ; Cruz-Oró, Eduard ; Franco-Zorrilla, José Manuel ; Prat, Salomé - \ 2016
Current Biology 26 (2016)7. - ISSN 0960-9822 - p. 872 - 881.
CONSTANS - FLOWERING LOCUS T - potato - tuberigen

The CONSTANS-FT pathway defines a core module for reproductive transition in both long-day (LD) and short-day (SD) plants. Changes in the transcriptional function of the CONSTANS (CO) protein have been proposed to mediate differential SD activation of FLOWERING LOCUS T (FT) orthologs in SD plants. Potato Andigena genotypes have an obligate SD requirement for tuber formation, and this photoperiodic response correlates with activation of the FT StSP6A gene in leaves. The potato StCOL1 factor represses expression of this mobile tuberization signal, but the control mechanism is poorly understood. Here, we analyzed StCOL1 diurnal oscillation and protein accumulation at different photoperiods and light wavelengths. We observed that the potato StCOL1 gene peaked at dawn and that, in contrast to the Arabidopsis AtCO homolog, the light receptor phyB is necessary for protein stabilization in the light. Reduced StCOL1 levels in RNAi lines strongly correlated with downregulated expression of an additional potato FT family member, StSP5G. Co-regulated StCOL1 and StSP5G expression suggested that StCOL1 activates this target directly rather than controlling StSP6A expression. By hybridization of a universal protein-binding microarray, we established that StCOL1 binds a TGTGGT element, and we found that immunoprecipitated StCOL1 protein fractions were enriched in StSP5G promoter fragments bearing this element. We show that StSP5G represses tuberization in LD conditions and that this FT-like homolog suppresses StSP6A gene expression. Rewiring StCOL1 transcriptional function from direct activation of the StSP6A inducer signal to the control of an FT-like repressor thus mediates the strict SD requirement of Andigena plants for tuberization.

Terug naar de basis
Willems, Arno ; Schreppers, Harrie ; Jans, Rino ; Klingen, Simon ; Ouden, J. den; Schoonderwoerd, Henny ; Wijdeven, Sander ; Staak, Erik van der - \ 2016
Vakblad Natuur Bos Landschap 13 (2016)127. - ISSN 1572-7610 - p. 40 - 41.
bosbeheer - houtachtige planten - duurzaamheid (sustainability) - bosgronden - bodemuitputting - bosecologie - voedingsstoffenbalans - verzuring - bodemverdichting - mechanisatie - forest administration - woody plants - sustainability - forest soils - soil exhaustion - forest ecology - nutrient balance - acidification - soil compaction - mechanization
Als bosbeheerders gaan we er prat op dat we het begrip duurzaamheid hebben uitgevonden. Dat is inderdaad iets om trots op te zijn en bewijst dat we als sector gewend zijn ver vooruit te kijken en te denken. Het is echter de vraag of we onze bossen nog wel volgens de principes van duurzaamheid beheren. Met name over de mogelijke uitputting van de bodem en de invloed van de exploitatie op de bodem bestaan veel vragen waarvan de antwoorden niet voor het oprapen liggen. Op 17 mei 2016 ging de Studiekring van de KNBV terug naar de basis: de bosbodem.
Progenitor-derived hepatocyte-like (B-13/H) cells metabolise 1'-hydroxyestragole to a genotoxic species via a SULT2B1-dependent mechanism
Probert, Philip M. ; Palmer, Jeremy M. ; Alhusainy, W. ; Amer, Aimen O. ; Rietjens, Ivonne M.C.M. ; White, Steven A. ; Jones, David E. ; Wright, Matthew C. - \ 2016
Toxicology Letters 243 (2016). - ISSN 0378-4274 - p. 98 - 110.
Comet - Estragole - Genotoxicity - Liver - Sulfotransferase

Rat B-13 progenitor cells are readily converted into functional hepatocyte-like B-13/H cells capable of phase I cytochrome P450-dependent activation of pro-carcinogens and induction of DNA damage. The aim of the present study was to investigate whether the cells are also capable of Phase II sulphotransferase (SULT)-dependent activation of a pro-carcinogen to an ultimate carcinogen. To this end we therefore examined the bioactivation of the model hepatic (hepato- and cholangio-) carcinogen estragole and its proximate SULT1A1-activated genotoxic metabolite 1'-hydroxyestragole. Exposing B-13 or B-13/H cells to estragole (at concentrations up to 1mM) resulted in the production of low levels of 1'-hydroxyestragole, but did not result in detectable DNA damage. Exposing B-13/H cells - but not B-13 cells - to 1'-hydroxyestragole resulted in a dose-dependent increase in DNA damage in comet assays, confirmed by detection of N2-(trans-isoestragol-3'-yl)-2'-deoxyguanosine adducts. Genotoxicity was inhibited by general SULT inhibitors, supporting a role for SULTS in the activation of 1-hydroxyestragole in B-13/H cells. However, B-13 and B-13/H cells did not express biologically significant levels of SULT1A1 as determined by qRT-PCR, Western blotting and its associated 7-hydroxycoumarin sulphation activity. B-13 and B-13/H cells expressed - relative to intact rat liver - high levels of SULT2B1 (primarily the b isoform) and SULT4A1 mRNAs and proteins. B-13 and B-13/H cells also expressed the 3'-phosphoadenosine 5'-phosphosulphate synthase 1 required for the generation of activated sulphate cofactor 3'-phosphoadenosine 5'-phosphosulphate. However, only B-13/H cells expressed functional SULT activities towards SULT2B1 substrates DHEA, pregnenolone and 4 methylumbelliferone. Since liver progenitor cells are bi-potential and also form cholangiocytes, we therefore hypothesised that B-13 cells express a cholangiocyte-like SULT profile. To test this hypothesis, the expression of SULTs was examined in liver by RT-PCR and immunohistochemistry. SULT2B1 - but not SULT1A1 - was determined to be expressed in both rat and human cholangiocytes. Since 1'-hydroxyestragole exposure readily produced DNA injury in B-13/H cells, these data suggest that cholangiocarcinomas generated in rats fed estragole may be dependent, in part, on SULT2B1 activation of the 1'-hydroxyestragole metabolite.

Evaluation and Selection of Indicators for Land Degradation and Desertification Monitoring: Types of Degradation, Causes, and Implications for Management
Kairis, O. ; Kosmas, C. ; Karavitis, C. ; Ritsema, C.J. ; Salvati, L. ; Acikalin, S. ; Alcala, M. ; Alfama, P. ; Atlhopheng, J. ; Barrera, J. ; Belgacem, A. ; Sole-Benet, A. ; Brito, J. ; Chaker, M. ; Chanda, R. ; Coelho, C. ; Darkoh, M. ; Diamantis, I. ; Ermolaeva, O. ; Fassouli, V. ; Fei, W. ; Feng, J. ; Fernandez, F. ; Ferreira, A. ; Gokceoglu, C. ; Gonzalez, D. ; Gungor, H. ; Hessel, R. ; Juying, J. ; Khatteli, H. ; Khitrov, N. ; Kounalaki, A. ; Laouina, A. ; Lollino, P. ; Lopes, M. ; Magole, L. ; Medina, L. ; Mendoza, M. ; Morais, P. ; Mulale, K. ; Ocakoglu, F. ; Ouessar, M. ; Ovalle, C. ; Perez, C. ; Perkins, J. ; Pliakas, F. ; Polemio, M. ; Pozo, A. ; Prat, C. ; Qinke, Y. ; Ramos, A. ; Ramos, J. ; Riquelme, J. ; Romanenkov, V. ; Rui, L. ; Santaloia, F. ; Sebego, R. ; Sghaier, M. ; Silva, N. ; Sizemskaya, M. ; Soares, J. ; Sonmez, H. ; Taamallah, H. ; Tezcan, L. ; Torri, D. ; Ungaro, F. ; Valente, S. ; Vente, J. de; Zagal, E. ; Zeiliguer, A. ; Zhonging, W. ; Ziogas, A. - \ 2014
Environmental Management 54 (2014)5. - ISSN 0364-152X - p. 971 - 982.
region ne spain - tillage erosion - soil displacement - translocation - vulnerability - sensitivity - performance - vegetation - systems - impact
Indicator-based approaches are often used to monitor land degradation and desertification from the global to the very local scale. However, there is still little agreement on which indicators may best reflect both status and trends of these phenomena. In this study, various processes of land degradation and desertification have been analyzed in 17 study sites around the world using a wide set of biophysical and socioeconomic indicators. The database described earlier in this issue by Kosmas and others (Environ Manage, 2013) for defining desertification risk was further analyzed to define the most important indicators related to the following degradation processes: water erosion in various land uses, tillage erosion, soil salinization, water stress, forest fires, and overgrazing. A correlation analysis was applied to the selected indicators in order to identify the most important variables contributing to each land degradation process. The analysis indicates that the most important indicators are: (i) rain seasonality affecting water erosion, water stress, and forest fires, (ii) slope gradient affecting water erosion, tillage erosion and water stress, and (iii) water scarcity soil salinization, water stress, and forest fires. Implementation of existing regulations or policies concerned with resources development and environmental sustainability was identified as the most important indicator of land protection.
Evaluation and Selection of Indicators for Land Degradation and Desertification Monitoring: Methodological Approach
Kosmas, C. ; Karis, O. ; Karavitis, C. ; Ritsema, C.J. ; Salvati, L. ; Acikalin, S. ; Alcala, S. ; Alfama, P. ; Atlhopheng, J. ; Barrera, J. ; Belgacem, A. ; Sole-Benet, A. ; Brito, J. ; Chaker, M. ; Chanda, R. ; Coelho, C. ; Darkoh, M. ; Diamantis, I. ; Ermolaeva, O. ; Fassouli, V. ; Fei, W. ; Fernandez, F. ; Ferreira, A. ; Gokceoglu, C. ; Gonzalez, D. ; Gungor, H. ; Hessel, R. ; Juying, J. ; Khatteli, H. ; Kounalaki, A. ; Laouina, A. ; Lollino, P. ; Lopes, M. ; Magole, L. ; Medina, L. ; Mendoza, M. ; Morais, P. ; Mulale, K. ; Ocakoglu, F. ; Ouessar, M. ; Ovalle, C. ; Perez, C. ; Perkins, J. ; Pliakas, F. ; Polemio, M. ; Pozo, A. ; Prat, C. ; Qinke, Y. ; Ramos, A. ; Riquelme, J. ; Romanenkov, V. ; Rui, L. ; Santaloia, F. ; Sebego, R. ; Sghaier, M. ; Silva, N. ; Sizemskaya, M. ; Soares, J. ; Sonmez, H. ; Taamallah, H. ; Tezcan, L. ; Torri, D. ; Ungaro, F. ; Valente, S. ; Vente, J. de; Zagal, E. ; Zeiliguer, A. ; Zhonging, W. ; Ziogas, A. - \ 2014
Environmental Management 54 (2014)5. - ISSN 0364-152X - p. 951 - 970.
mediterranean conditions - aggregate stability - soil properties - rock fragments - organic-matter - vegetation - tillage - biomass - erosion - greece
An approach to derive relationships for defining land degradation and desertification risk and developing appropriate tools for assessing the effectiveness of the various land management practices using indicators is presented in the present paper. In order to investigate which indicators are most effective in assessing the level of desertification risk, a total of 70 candidate indicators was selected providing information for the biophysical environment, socio-economic conditions, and land management characteristics. The indicators were defined in 1,672 field sites located in 17 study areas in the Mediterranean region, Eastern Europe, Latin America, Africa, and Asia. Based on an existing geo-referenced database, classes were designated for each indicator and a sensitivity score to desertification was assigned to each class based on existing research. The obtained data were analyzed for the various processes of land degradation at farm level. The derived methodology was assessed using independent indicators, such as the measured soil erosion rate, and the organic matter content of the soil. Based on regression analyses, the collected indicator set can be reduced to a number of effective indicators ranging from 8 to 17 in the various processes of land degradation. Among the most important indicators identified as affecting land degradation and desertification risk were rain seasonality, slope gradient, plant cover, rate of land abandonment, land-use intensity, and the level of policy implementation.
Naturally occurring allele diversity allows potato cultivation in northern latitudes
Kloosterman, B.A. ; Abelenda, J.A. ; Carretero Gomez, M. ; Oortwijn, M.E.P. ; Boer, J.M. de; Kowitwanich, K. ; Horvath, B.M. ; Eck, H.J. van; Smaczniak, C. ; Prat, S. ; Visser, R.G.F. ; Bachem, C.W.B. - \ 2013
Nature 495 (2013)7440. - ISSN 0028-0836 - p. 246 - 250.
flowering-time - arabidopsis - constans - tuberization - gene - plants - fkf1
Potato (Solanum tuberosum L.) originates from the Andes and evolved short-day-dependent tuber formation as a vegetative propagation strategy. Here we describe the identification of a central regulator underlying a major-effect quantitative trait locus for plant maturity and initiation of tuber development. We show that this gene belongs to the family of DOF (DNA-binding with one finger) transcription factors1 and regulates tuberization and plant life cycle length, by acting as a mediator between the circadian clock and the StSP6A mobile tuberization signal2. We also show that natural allelic variants evade post-translational light regulation, allowing cultivation outside the geographical centre of origin of potato. Potato is a member of the Solanaceae family and isone of the world’s most important food crops. This annual plant originates from the Andean regions of South America3. Potato develops tubers from underground stems called stolons. Its equatorial origin makes potato essentially short-day dependent for tuberization and potato will not make tubers in the long-day conditions of spring and summer in the northern latitudes. When introduced in temperate zones, wild material will form tubers in the course of the autumnal shortening of day-length. Thus, one of the first selected traits in potato leading to a European potato type4 is likely to have been long-day acclimation for tuberization. Potato breeders can exploit the naturally occurring variation in tuberization onset and life cycle length, allowing varietal breeding for different latitudes, harvest times and markets.
A novel approach to analysing the regimes of temporary streams in relation to their controls on the composition and structure of aquatic biota
Gallart, F. ; Prat, N. ; Garcia-Roger, E.M. ; Latron, J. ; Rieradevall, M. ; Liorens, P. ; Barbera, G.G. ; Brito, D. ; Girolamo, A. De; Porto, A. Lo; Buffagni, A. ; Erba, S. ; Neves, R. ; Nikolaidis, N.P. ; Perrin, L. ; Querner, E.P. ; Quinonero, J.M. ; Tournoud, M.G. ; Tzoraki, O. ; Skoulikidis, N. ; Gomez, R. ; Sanchez-Montoya, M.M. ; Froebrich, J. - \ 2012
Hydrology and Earth System Sciences 16 (2012)9. - ISSN 1027-5606 - p. 3165 - 3182.
benthic macroinvertebrate assemblages - mediterranean streams - intermittent streams - community structure - ephemeral channels - habitat features - fish assemblages - flow permanence - river health - drought
Temporary streams are those water courses that undergo the recurrent cessation of flow or the complete drying of their channel. The structure and composition of biological communities in temporary stream reaches are strongly dependent on the temporal changes of the aquatic habitats determined by the hydrological conditions. Therefore, the structural and functional characteristics of aquatic fauna to assess the ecological quality of a temporary stream reach cannot be used without taking into account the controls imposed by the hydrological regime. This paper develops methods for analysing temporary streams' aquatic regimes, based on the definition of six aquatic states that summarize the transient sets of mesohabitats occurring on a given reach at a particular moment, depending on the hydrological conditions: Hyperrheic, Eurheic, Oligorheic, Arheic, Hyporheic and Edaphic. When the hydrological conditions lead to a change in the aquatic state, the structure and composition of the aquatic community changes according to the new set of available habitats. We used the water discharge records from gauging stations or simulations with rainfall-runoff models to infer the temporal patterns of occurrence of these states in the Aquatic States Frequency Graph we developed. The visual analysis of this graph is complemented by the development of two metrics which describe the permanence of flow and the seasonal predictability of zero flow periods. Finally, a classification of temporary streams in four aquatic regimes in terms of their influence over the development of aquatic life is updated from the existing classifications, with stream aquatic regimes defined as Permanent, Temporary-pools, Temporary-dry and Episodic. While aquatic regimes describe the long-term overall variability of the hydrological conditions of the river section and have been used for many years by hydrologists and ecologists, aquatic states describe the availability of mesohabitats in given periods that determine the presence of different biotic assemblages. This novel concept links hydrological and ecological conditions in a unique way. All these methods were implemented with data from eight temporary streams around the Mediterranean within the MIRAGE project. Their application was a precondition to assessing the ecological quality of these streams.
Developing a novel approach to analyse the regimes of temporary streams and their controls on aquatic biota
Gallart, F. ; Prat, N. ; Garcia-Roger, E.M. ; Latron, J. ; Rieradevall, M. ; Llorens, P. ; Barbera, G.G. ; Froebrich, J. - \ 2011
Hydrology and Earth System Sciences Discussions 8 (2011)5. - ISSN 1812-2108 - p. 9637 - 9673.
Temporary streams are those water courses that undergo the recurrent cessation of flow or the complete drying of their channel. The biological communities in temporary stream reaches are strongly dependent on the temporal changes of the aquatic habitats determined by the hydrological conditions. The use of the aquatic fauna structural and functional characteristics to assess the ecological quality of a temporary stream reach can not therefore be made without taking into account the controls imposed by the hydrological regime. This paper develops some methods for analysing temporary streams' aquatic regimes, based on the definition of six aquatic states that summarize the sets of mesohabitats occurring on a given reach at a particular moment, depending on the hydrological conditions: flood, riffles, connected, pools, dry and arid. We used the water discharge records from gauging stations or simulations using rainfall-runoff models to infer the temporal patterns of occurrence of these states using the developed aquatic states frequency graph. The visual analysis of this graph is complemented by the development of two metrics based on the permanence of flow and the seasonal predictability of zero flow periods. Finally, a classification of the aquatic regimes of temporary streams in terms of their influence over the development of aquatic life is put forward, defining Permanent, Temporary-pools, Temporary-dry and Episodic regime types. All these methods were tested with data from eight temporary streams around the Mediterranean from MIRAGE project and its application was a precondition to assess the ecological quality of these streams using the current methods prescribed in the European Water Framework Directive for macroinvertebrate communities.
Hydrological analysis of the Evrotas basin, Greece - Low flow characterization and scenario analisis
Cazemier, M. ; Querner, E.P. ; Lanen, H.A.J. van; Gallart, F. ; Prat, N. ; Tzoraki, O. ; Froebrich, J. - \ 2011
Wageningen : Alterra (Alterra-rapport 2249) - 92
hydrologie - waterlopen - aquatische ecologie - griekenland - stroming - seizoengebondenheid - hydrology - streams - aquatic ecology - greece - flow - seasonality
Genes driving potato tuber initiation and growth: identification based on transcriptional changes using the POCI array
Kloosterman, B.A. ; Koeyer, D. de; Griffiths, R. ; Flinn, B. ; Steuernagel, B. ; Scholz, U. ; Sonnewald, S. ; Sonnewald, U. ; Bryan, G.J. ; Prat, S. ; Banfalvi, Z. ; Hammond, J.P. ; Geigenberger, P. ; Nielsen, K.L. ; Visser, R.G.F. ; Bachem, C.W.B. - \ 2008
Functional and Integrative Genomics 8 (2008)4. - ISSN 1438-793X - p. 329 - 340.
expressed sequence tags - libraries - search
The increasing amount of available expressed gene sequence data makes whole-transcriptome analysis of certain crop species possible. Potato currently has the second largest number of publicly available expressed sequence tag (EST) sequences among the Solanaceae. Most of these ESTs, plus other proprietary sequences, were combined and used to generate a unigene assembly. The set of 246,182 sequences produced 46,345 unigenes, which were used to design a 44K 60-mer oligo array (Potato Oligo Chip Initiative: POCI). In this study, we attempt to identify genes controlling and driving the process of tuber initiation and growth by implementing large-scale transcriptional changes using the newly developed POCI array. Major gene expression profiles could be identified exhibiting differential expression at key developmental stages. These profiles were associated with functional roles in cell division and growth. A subset of genes involved in the regulation of the cell cycle, based on their Gene Ontology classification, exhibit a clear transient upregulation at tuber onset indicating increased cell division during these stages. The POCI array allows the study of potato gene expression on a much broader level than previously possible and will greatly enhance analysis of transcriptional control mechanisms in a wide range of potato research areas. POCI sequence and annotation data are publicly available through the POCI database
StGA2ox1 is induced prior to stolon swelling and controls GA levels during potato tuber development
Kloosterman, B.A. ; Navarro, C. ; Bijsterbosch, G. ; Lange, Theo ; Prat, S. ; Visser, R.G.F. ; Bachem, C.W.B. - \ 2007
The Plant Journal 52 (2007)2. - ISSN 0960-7412 - p. 362 - 373.
differential gene-expression - gibberellin metabolism - phytochrome-b - solanum-tuberosum - transcript levels - 20-oxidase gene - in-vitro - tuberization - biosynthesis - antirrhinum
The formation and growth of a potato (Solanum tuberosum) tuber is a complex process regulated by different environmental signals and plant hormones. In particular, the action of gibberellins (GAs) has been implicated in different aspects of potato tuber formation. Here we report on the isolation and functional analysis of a potato GA 2-oxidase gene (StGA2ox1) and its role in tuber formation. StGA2ox1 is upregulated during the early stages of potato tuber development prior to visible swelling and is predominantly expressed in the subapical region of the stolon and growing tuber. 35S-over-expression transformants exhibit a dwarf phenotype, reduced stolon growth and earlier in vitro tuberization. Transgenic plants with reduced expression levels of StGA2ox1 showed normal plant growth, an altered stolon swelling phenotype and delayed in vitro tuberization. Tubers of the StGA2ox1 suppression clones contain increased levels of GA20, indicating altered GA metabolism. We propose a role for StGA2ox1 in early tuber initiation by modifying GA levels in the subapical stolon region at the onset of tuberization, thereby facilitating normal tuber development and growth.
Soil health scenario's
Faber, J.H. ; Pol, J.J.C. van der; Thomsen, M. - \ 2006
In: Pre-selection of scenario for cumulative risk assessment : documentation of the first version of selection procedure including initial uncertaicty evaluation / Thomsen, M., Sorensen, P.B., Fauser, P., Faber, J., van der Pol, J., Peirano, F., Magnetti Vernai, A., Strebel, K., Schlink, U., Espinosa Porragas, G., Giralt i Prat, F., Rallo, R., Pistocchi, A., [S.l.] : [s.n.] (Report Deliverable D.1.2.4.) - p. 64 - 78.
Pre-selection of scenario for cumulative risk assessment; documentation of the first version for selection procedure including initial uncertainty evaluation
Thomsen, M. ; Sorensen, P.B. ; Fauser, P. ; Faber, J.H. ; Pol, J.J.C. van der; Peirano, F. ; Magnetti Vernai, A. ; Strebel, K. ; Schlink, U. ; Espinosa Porragas, G. ; Giralt i Prat, F. ; Rallo, R. ; Pistocchi, A. - \ 2006
S.l. : s.n. (NoMiracle Deliverable D.1.2.4) - 215
risicoschatting - modellen - methodologie - onzekerheid - ecotoxicologie - risk assessment - models - methodology - uncertainty - ecotoxicology
The mapping of phytochrome genes and photomorphogenic mutants of tomato.
Tuinen, A. van; Cordonnier-Prat, M.M. ; Pratt, L.H. ; Verkerk, R. ; Zabel, P. ; Koornneef, M. - \ 1997
Theoretical and Applied Genetics 94 (1997)1. - ISSN 0040-5752 - p. 115 - 122.
'Replicationfree' optimal designs in regression analysis.
Rasch, D.A.M.K. - \ 1996
In: Proceedings in Computational Statistics. Physica Verlag Heidelberg / Prat, A., - p. 403 - 409.
Propagation and regeneration of Salix alba in vitro
Evers, P.W. ; Haanstra, L. ; Prat, A. ; Eeden, S.J. van - \ 1995
Wageningen : Institute for Forestry and Nature Research (IBN Research Report 95/8) - 57 p.
Rejuvenation and micropropagation of Quercus suber
Evers, P.W. ; Haanstra, L. ; Prat, A. ; Vermeer, E. - \ 1995
Wageningen : Institute for Forestry and Nature Research (IBN Research Report 95/6) - 27 p.
Vermeerderingsonderzoek aan populier in kweekbuizen
Evers, P. ; Prat, A. - \ 1984
Populier 21 (1984)1. - ISSN 0166-7491 - p. 17 - 20.
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