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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The effector GpRbp-1 of Globodera pallida targets a nuclear HECT E3 ubiquitin ligase to modulate gene expression in the host
Diaz-Granados, Amalia ; Sterken, Mark G. ; Overmars, Hein ; Ariaans, Roel ; Holterman, Martijn ; Pokhare, Somnath S. ; Yuan, Yulin ; Pomp, Rikus ; Finkers-Tomczak, Anna ; Roosien, Jan ; Slootweg, Erik ; Elashry, Abdenaser ; Grundler, Florian M.W. ; Xiao, Fangming ; Goverse, Aska ; Smant, Geert - \ 2020
Molecular Plant Pathology 21 (2020)1. - ISSN 1464-6722 - p. 66 - 82.
Cyst nematodes - GpRbp-1 - HECT E3 ligase - nematode effectors - ubiquitination - UPL3 - virulence/parasitism

Plant-parasitic nematodes secrete effectors that manipulate plant cell morphology and physiology to achieve host invasion and establish permanent feeding sites. Effectors from the highly expanded SPRYSEC (SPRY domain with a signal peptide for secretion) family in potato cyst nematodes have been implicated in activation and suppression of plant immunity, but the mechanisms underlying these activities remain largely unexplored. To study the host mechanisms used by SPRYSEC effectors, we identified plant targets of GpRbp-1 from the potato cyst nematode Globodera pallida. Here, we show that GpRbp-1 interacts in yeast and in planta with a functional potato homologue of the Homology to E6-AP C-Terminus (HECT)-type ubiquitin E3 ligase UPL3, which is located in the nucleus. Potato lines lacking StUPL3 are not available, but the Arabidopsis mutant upl3-5 displaying a reduced UPL3 expression showed a consistently small but not significant decrease in susceptibility to cyst nematodes. We observed a major impact on the root transcriptome by the lower levels of AtUPL3 in the upl3-5 mutant, but surprisingly only in association with infections by cyst nematodes. To our knowledge, this is the first example that a HECT-type ubiquitin E3 ligase is targeted by a pathogen effector and that a member of this class of proteins specifically regulates gene expression under biotic stress conditions. Together, our data suggest that GpRbp-1 targets a specific component of the plant ubiquitination machinery to manipulate the stress response in host cells.

Do diverse landscapes provide for effective natural pest control in subtropical rice?
Zou, Yi ; Kraker, Joop De; Bianchi, Felix J.J.A. ; Xiao, Haijun ; Huang, Jikun ; Deng, Xiangzheng ; Hou, Lingling ; Werf, Wopke Van Der - \ 2020
Journal of Applied Ecology 57 (2020)1. - ISSN 0021-8901 - p. 170 - 180.
While the biocontrol potential of natural enemies is well established, it is largely unknown how landscape‐mediated effects on pest and natural enemy communities impact the cascade of biocontrol potential, crop injury, yield and profit, taking into account crop management and surrounding landscape composition.We compared natural biocontrol with chemical control according to local farmers’ practice, across the ‘full cascade’ from natural enemy and pest abundance to crop injury, yield loss, yield and economic performance. This two‐year study was conducted in 20 rice fields embedded in a gradient of landscapes from crop‐dominated to semi‐natural habitat‐dominated, in subtropical China, the world's largest rice producing region.Natural enemies suppressed brown planthopper population growth in unsprayed plots, irrespective of landscape composition. However, crop injury was lower in pesticide treated plots than in unsprayed plots, and yields in sprayed plots were 20% higher than in unsprayed plots. Nevertheless, pesticide applications were only profitable in less than half of the cases when only costs for pesticides were considered, and in less than one third of the cases when costs for pesticides and labour were considered.Synthesis and applications. Our findings question the cost‐effectiveness of current chemical‐based pest management in farming, and highlight opportunities for more ecologically based pest management strategies based on the widespread activity of natural enemies. Pest damage and biocontrol, however, are largely independent from the landscape context, which might be due to the small‐scale character of Chinese rice landscapes. To maintain high levels of biocontrol, conserving this small‐scale character appears more important than increasing the proportion of semi‐natural habitat
Genome-wide transcriptome analysis reveals molecular pathways involved in leafy head formation of Chinese cabbage (Brassica rapa)
Sun, Xiao Xue ; Basnet, Ram Kumar ; Yan, Zhichun ; Bucher, Johan ; Cai, Chengcheng ; Zhao, Jianjun ; Bonnema, Guusje - \ 2019
Horticulture Research 6 (2019)1. - ISSN 2052-7276

Chinese cabbage plants go through seedling and rosette stages before forming their leafy head. Chinese cabbage plants resemble pak-choi plants at their seedling stage, but in their rosette stage the leaves of Chinese cabbage differentiate, as they increase in size with shorter petioles. In order to understand the molecular pathways that play a role in leafy head formation, transcript abundance of young emerging leaves was profiled during development of two Chinese cabbage genotypes and a single pak-choi genotype. The two Chinese cabbages differed in many aspects, among others earliness, leaf size and shape, leaf numbers, and leafy head shape. Genome-wide transcriptome analysis clearly separated the seedling stages of all three genotypes together with the later stages from pak-choi, from the later developmental stages of both Chinese cabbages (rosette, folding, and heading). Weighted correlation network analysis and hierarchical clustering using Euclidean distances resulted in gene clusters with transcript abundance patterns distinguishing the two Chinese cabbages from pak-choi. Three clusters included genes with transcript abundance affected by both genotype and developmental stage, whereas two clusters showed only genotype effects. This included a genotype by developmental stage cluster highly enriched with the MapMan category photosynthesis, with high expression during rosette and folding in Chinese cabbages and low expression in the heading inner leaves that are not exposed to light. The other clusters contained many genes in the MapMan categories Cell, showing again differences between pak-choi and both Chinese cabbages. We discuss how this relates to the differences in leaf blade growth between Chinese cabbage and pak-choi, especially at the rosette stage. Overall, comparison of the transcriptome between leaves of two very different Chinese cabbages with pak-choi during plant development allowed the identification of specific gene categories associated with leafy head formation.

Lateral root formation involving cell division in both pericycle, cortex and endodermis is a common and ancestral trait in seed plants
Xiao, Ting Ting ; Velzen, Robin van; Kulikova, Olga ; Franken, Carolien ; Bisseling, Ton - \ 2019
Development 146 (2019)20. - ISSN 0950-1991
Endodermis - Lateral root development - Medicago - Primordium - Quiescent centre - Stem cells

Studies on the model plant Arabidopsis have led to the common view that lateral roots are exclusively formed from pericycle cells and that the latter are unique in their ability to be reprogrammed into stem cells. By analysing lateral root formation in an evolutionary context, we show that lateral root primordium formation in which cortex, endodermis and pericycle are mitotically activated, is a common and ancestral trait in seed plants, whereas the exclusive involvement of pericycle evolved in the Brassicaceae. Furthermore, the endodermis can also be reprogrammed into stem cells in some species.

Self-assembled egg yolk peptide micellar nanoparticles as a versatile emulsifier for food-grade oil-in-water pickering nanoemulsions
Du, Zhenya ; Li, Qing ; Li, Junguang ; Su, Enyi ; Liu, Xiao ; Wan, Zhili ; Yang, Xiaoquan - \ 2019
Journal of Agricultural and Food Chemistry 67 (2019)42. - ISSN 0021-8561 - p. 11728 - 11740.
Egg yolk peptides - Food-grade pickering nanoemulsions - Nanomicelles - Particulate emulsifiers - Self-assembly

Pickering emulsions stabilized by food-grade particles have garnered increasing interest in recent years due to their promising applications in bio-related fields such as foods, cosmetics, and drug delivery. However, it remains a big challenge to formulate nanoscale Pickering emulsions from these edible particles. Herein, we show that a new Pickering nanoemulsion that is stable, monodisperse and controllable can be produced by employing the spherical micellar nanoparticles (EYPN), self- A ssembled from the food-derived, amphiphilic egg yolk peptides, as an edible particulate emulsifier. As natural peptide-based nanoparticles, the EYPN have small particle size, intermediate wettability, high surface activity, and deformability at the interface, which enable the formation of stable Pickering nanodroplets with a mean DLS diameter below 200 nm and a PDI below 0.2. This nanoparticle system is versatile for different oil phases with various polarities and demonstrates easy control of nanodroplet size through tuning the microfluidization conditions and/or the ratio of EYPN to oil phase. These food-grade Pickering nanoemulsions, obtained when the internal phase is an edible vegetable oil, have superior stability during long-term storage and spray-drying, based on the irreversible and compact adsorption of intact EYPN at the nanodroplet surface. This is the first finding of a natural edible nano-Pickering emulsifier that can be used solely to make stable food Pickering nanoemulsions with the qualities of simplicity, versatility, low cost, and the possibility of controllable and mass production, which make them viable for many sustainable applications.

Do diverse landscapes provide for effective natural pest control in subtropical rice?
Zou, Y. ; Kraker, Joop de; Bianchi, F.J.J.A. ; Xiao, Haijun ; Huang, Jikun ; Deng, Xiangzheng ; Hou, Lingling ; Werf, W. van der - \ 2019
Wageningen University & Research
agroecosystem - biological pest control - China - natural enemy - pest - planthopper - yield
This datasets comprises data from 20 rice fields embedded in a gradient of landscapes from crop-dominated to semi-natural habitat-dominated, in the Jiangxi Province in China in 2014 and 2015. Each field was split into two plots: in one plot no pesticides were applied and in the other plot farmers applied pesticides according to their normal pest management practices. The dataset comprises information on the focal rice fields, the land use surrounding the focal rice fields, arthropod abundances and diversity, crop damage, an exclusion experiment to assess the potential of natural enemies to suppress pests, pest management practices and rice yield
Editorial: Organ Modification for Edible Parts of Horticultural Crops
He, Yuke ; Bonnema, Guusje ; Xiao, Han ; Zhao, Yunde - \ 2019
Frontiers in Plant Science 10 (2019). - ISSN 1664-462X
bulb - corm - curd - fleshy fruit - fleshy root - leafy head - morphological modification - tuber
Development of a low-alcoholic fermented beverage employing cashew apple juice and non-conventional yeasts
Gamero, Amparo ; Ren, Xiao ; Lamboni, Yendouban ; Jong, Catrienus de; Smid, Eddy J. ; Linnemann, Anita R. - \ 2019
Fermentation 5 (2019)3. - ISSN 2311-5637
Alcoholic beverages - Aroma profile - Cashew apple juice - Hanseniaspora guilliermondii - Non‐conventional yeasts - Saccharomyces cerevisiae - Torulaspora microellipsoides

Cashew apples are by‐products in the production of cashew nuts, which are mostly left to rot in the fields. Cashew apple juice (CAJ), a highly nutritious beverage, can be produced from them. It is rich in sugars and ascorbic acid, but its high polyphenol content makes it bitter and astringent, and therefore difficult to commercialize. The kingdom of fungi contains more than 2000 yeast species, of which only a few species have been studied in relation to their potential to produce aroma compounds. The aim of this research was to develop a new low‐alcoholic fermented beverage to valorize cashew apples. For this purpose, a screening was carried out employing non‐conventional yeast species and some species of the genus Saccharomyces for comparison, followed by a more detailed study with four selected strains cultured at different conditions. The production of volatile aroma compounds as a function of the presence of oxygen, temperature, and yeast species was investigated. The results showed that the more diverse aroma profiles appeared at 25 °C under anaerobic cultivation conditions, where Saccharomyces cerevisiae WUR 102 and Hanseniaspora guilliermondii CBS 2567 excelled in the synthesis of certain aroma compounds, such as β-phenylethanol and its acetate ester (rose aroma). Further studies are needed to test consumer acceptance of these new products.

A Medicago truncatula SWEET transporter implicated in arbuscule maintenance during arbuscular mycorrhizal symbiosis
An, Jianyong ; Zeng, Tian ; Ji, Chuanya ; Graaf, Sanne de; Zheng, Zijun ; Xiao, Ting Ting ; Deng, Xiuxin ; Xiao, Shunyuan ; Bisseling, Ton ; Limpens, Erik ; Pan, Zhiyong - \ 2019
New Phytologist 224 (2019)1. - ISSN 0028-646X - p. 396 - 408.
arbuscular mycorrhiza (AM) - glucose - Medicago truncatula - sugar export - SWEET - symbiosis

Plants form a mutualistic symbiosis with arbuscular mycorrhizal (AM) fungi, which facilitates the acquisition of scarce minerals from the soil. In return, the host plants provide sugars and lipids to its fungal partner. However, the mechanism by which the AM fungi obtain sugars from the plant has remained elusive. In this study we investigated the role of potential SWEET family sugar exporters in AM symbiosis in Medicago truncatula. We show that M. truncatula SWEET1b transporter is strongly upregulated in arbuscule-containing cells compared to roots and localizes to the peri-arbuscular membrane, across which nutrient exchange takes place. Heterologous expression of MtSWEET1b in a yeast hexose transport mutant showed that it mainly transports glucose. Overexpression of MtSWEET1b in M. truncatula roots promoted the growth of intraradical mycelium during AM symbiosis. Surprisingly, two independent Mtsweet1b mutants, which are predicted to produce truncated protein variants impaired in glucose transport, exhibited no significant defects in AM symbiosis. However, arbuscule-specific overexpression of MtSWEET1bY57A/G58D, which are considered to act in a dominant-negative manner, resulted in enhanced collapse of arbuscules. Taken together, our results reveal a (redundant) role for MtSWEET1b in the transport of glucose across the peri-arbuscular membrane to maintain arbuscules for a healthy mutually beneficial symbiosis.

Transcriptome analysis of virulence-differentiated Fusarium oxysporum f. Sp. Cucumerinum isolates during cucumber colonisation reveals pathogenicity profiles
Huang, Xiao Qing ; Lu, Xiao Hong ; Sun, Man Hong ; Guo, Rong Jun ; Diepeningen, Anne D. Van; Li, Shi Dong - \ 2019
BMC Genomics 20 (2019)1. - ISSN 1471-2164
Cucumber Fusarium wilt - Differentially expressed genes - Fusarium oxysporum f. Sp. Cucumerinum - Transposon - Virulence variation

Background: Cucumber Fusarium wilt, caused by Fusarium oxysporum f. Sp. Cucumerinum (Foc), is one of the most notorious diseases in cucumber production. Our previous research showed the virulence of Foc significantly increases over consecutive rounds of infection in a resistant cultivar. To understand the virulence variation of Foc under host pressure, the mildly virulent strain foc-3b (WT) and its virulence-enhanced variant Ra-4 (InVir) were selected and their transcriptome profiles in infected cucumber roots were analyzed at 24 h after inoculation (hai) and 120 hai. Results: A series of differentially expressed genes (DEGs) potentially involved in fungal pathogenicity and pathogenicity variation were identified and prove mainly involved in metabolic, transport, oxidation-reduction, cell wall degradation, macromolecules modification, and stress and defense. Among these DEGs, 190 up- and 360 down-regulated genes were expressed in both strains, indicating their importance in Foc infection. Besides, 286 and 366 DEGs showed up-regulated expression, while 492 and 214 showed down-regulated expression in InVir at 24 and 120 hai, respectively. These DEGs may be involved in increased virulence. Notably, transposases were more active in InVir than WT, indicating transposons may contribute to adaptive evolution. Conclusions: By a comparative transcriptome analysis of the mildly and highly virulent strains of Foc during infection of cucumber, a series of DEGs were identified that may be associated with virulence. Hence, this study provides new insight into the transcriptomic profile underlying pathogenicity and virulence differentiation of Foc.

A Natural Supramolecular Saponin Hydrogelator for Creation of Ultrastable and Thermostimulable Food-Grade Foams
Ma, Lulu ; Li, Qing ; Du, Zhenya ; Su, Enyi ; Liu, Xiao ; Wan, Zhili ; Yang, Xiaoquan - \ 2019
Advanced Material Interfaces 6 (2019)14. - ISSN 2196-7350
glycyrrhizic acid - responsive foams - saponin nanofibrils - supramolecular self-assembly - ultrastability

A new class of food-grade foams that are ultrastable, thermostimulable, and processable can be created simply by using the naturally occurring saponin glycyrrhizic acid (GA) as the sole stabilizer. The creation of this “superfoam” is based on the spatially controllable self-assembly of supramolecular GA nanofibril hydrogelators at the air–water interface and in the continuous phase. The rapid adsorption of GA nanofibrils at the bubble surface, forming a multilayer interfacial network, combined with the formation of viscoelastic fibrillar hydrogel networks in the continuous phase, enables the foams having ultrastability over months or years without the water drainage induced phase separation, which have been evidenced using small angle X-ray scattering and microscopy techniques. Such ultrastable foams can be rapidly destabilized on demand by heating, which induces the melting of the fibrillar networks. These thermoresponsive foams can be reversibly switched between stable and unstable by simply changing the temperature, based on the reversible gel–sol phase transition of the supramolecular hydrogel inside the foam. This is the first finding of a natural edible surfactant system that foams very well and can be used solely to make advanced foams with the qualities of simplicity, ultrastability, stimulability, and processability, which make them viable for many sustainable applications.

Introduction of polar or nonpolar groups at the hydroquinone units can lead to the destruction of the columnar structure of Pillar[5]arenes
Wang, Xiao ; Chen, R.X. ; Sue, Andrew C.H. ; Zuilhof, Han ; Aquino, Adelia J.A. ; Lischka, Hans - \ 2019
Computational and Theoretical Chemistry 1161 (2019). - ISSN 2210-271X - p. 1 - 9.
Alkyl group - Density functional theory - Energy barriers - Polar group

Pillar[5]arenes, a type of novel macrocycles containing di-substituted hydroquinone units linked by methylene bridges in para-positions, have attracted extensive attention in supramolecular chemistry as interesting candidates to be used in the preparation of host-guest complexes. Functionalization by means of rim substitution and sustaining an ordered substituent arrangement on both sides of the rim is important for the development of new pillararene-based materials. In order to achieve this, the rim inversion process of rotating the hydroquinone units through the pillar[5]arenes has to be controlled. In this context we have studied the effect of different types of hydroquinone substituents on the rotational energy profile using density functional theory combined with the hybrid M06-2X functional. The influence of polar ([sbnd]CH2F, [sbnd]CH2Cl, [sbnd]CH2OH, [sbnd]CH2SH, [sbnd]CH2NH2) and nonpolar alkyl ([sbnd]CH3, [sbnd]CH2CH3, [sbnd]CH2CH2CH3, [sbnd]CH(CH3)2 and [sbnd]CH2CH2CH2CH3) substituents on the on the energy barriers of the rotation mechanism, and different local minima was investigated. The stabilization of the intermediate structures by non-covalent van der Waals and interactions and also by hydrogen bonds constitute a major factor affecting barrier heights. In case of polar substituents, the largest barriers were found for [sbnd]CH2OH and [sbnd]CH3 substitutions and the lowest ones for [sbnd]CH2SH and [sbnd]CH2NH2. For the alkyl series, the barrier decreased significantly up to propyl due to increasing stabilizing dispersion interactions while it increased again for n-butyl since the chain did not fit in well the cavity to rotate through.

Individual performance in a coopetitive R&D alliance: motivation, opportunity and ability
Wang, Xiao ; Dolfsma, Wilfred ; Bij, Hans van der - \ 2019
R&D Management 49 (2019)5. - ISSN 0033-6807 - p. 762 - 774.

This study examines individual knowledge sharing in a coopetitive R&D alliance. R&D is increasingly carried out in an R&D alliance setting, where individuals share highly specialized tacit knowledge crossing firm boundaries. A particular challenging setting is the coopetitive R&D alliance, where partner firms partially compete and individuals may leak competitive knowledge. This setting has been studied on the level of the partner firm. We want to deepen insights by examining the individual level. Drawing on the motivation-opportunity-ability framework, we study the influence of individuals’ job experience (ability) on their performance in the alliance. We also examine effects of two- and three-way interactions between job experience, a central position in the social alliance network (opportunity) and intrinsic and extrinsic motivation. We find a positive association of job experience with individual performance, a positive interaction between job experience and extrinsic motivation and a positive three-way interaction between job experience, central network position and intrinsic motivation, and discuss the impact of these findings.

Potential impact of hydrodynamic shear force in aquifer thermal energy storage on dissolved organic matter releasement : A vigorous shaking batch study
Ni, Zhuobiao ; Li, Xiao ; Wang, Yafei ; Wang, Yue ; Qiu, Rongliang ; Rijnaarts, Huub ; Grotenhuis, Tim - \ 2019
Science of the Total Environment 677 (2019). - ISSN 0048-9697 - p. 263 - 271.
Aquifer thermal energy storage (ATES) - Bioremediation - COD - Dissolved organic matter (DOM) - Hydrodynamic shear force - TOC

The combination of bioremediation and aquifer thermal energy storage (ATES) has become attractive because of the possibility of solving environmental and energy problems simultaneously. While the impact of ATES on groundwater quality due to temperature change has received ample attention in literature, the effect of the greatly enhanced groundwater flow velocity on groundwater quality has not yet received sufficient scientific attention. To fill this gap in understanding, we conducted a simple yet straightforward experiment to illustrate the impact of hydrodynamic shear force due to the water flow by ATES on the release of dissolved organic matter, which can potentially be advantageous to bioremediation. Vigorous shaking conditions were applied to simulate the enhanced dynamics at the ATES well center and nearby. As the indicators of dissolved organic matter, COD and TOC concentrations were significantly impacted by shaking. COD increased from 5.4 mgO 2 /L to 36.3 mgO 2 /L during horizontal shaking. The maximum COD level was determined as 33.8 mgO 2 /L during orbital shaking, while the TOC level was growing from 6.7 to 28.7 mg C/L. Meanwhile, redox potential (with initial level -100 mV) was decreasing to -450 mV synchronously with the elevating COD and TOC level. Temperature was also revealed as a significant factor in the organic matter releasement. Microbial iron reduction was deemed to occur, yet sulfate reduction was not initiated during the whole experiment. Eventually, the structure of the soil-water matrix has been changed due to the extensive hydraulic and particle collisions, resulting in blackish appearance and thicker layer of fine particles. Overall, the findings advance our understanding of the role of the ATES-induced water flow in the subsurface biogeochemistry and give insight into the perspective of the combination of bioremediation and ATES. In general, an increase in dissolved organic matter can be expected due to the increased shear force at high flow conditions in the ATES system.

Airborne host–plant manipulation by whiteflies via an inducible blend of plant volatiles
Zhang, Peng Jun ; Wei, Jia Ning ; Zhao, Chan ; Zhang, Ya Fen ; Li, Chuan You ; Liu, Shu Sheng ; Dicke, Marcel ; Yu, Xiao Ping ; Turlings, Ted C.J. - \ 2019
Proceedings of the National Academy of Sciences of the United States of America 116 (2019)15. - ISSN 0027-8424 - p. 7387 - 7396.
Herbivore-induced plant volatiles - Jasmonic acid - Salicylic acid - Tomato - Whiteflies

The whitefly Bemisia tabaci is one of the world’s most important invasive crop pests, possibly because it manipulates plant defense signaling. Upon infestation by whiteflies, plants mobilize salicylic acid (SA)-dependent defenses, which mainly target pathogens. In contrast, jasmonic acid (JA)-dependent defenses are gradually suppressed in whitefly-infested plants. The down-regulation of JA defenses make plants more susceptible to insects, including whiteflies. Here, we report that this host–plant manipulation extends to neighboring plants via airborne signals. Plants respond to insect attack with the release of a blend of inducible volatiles. Perception of these volatiles by neighboring plants usually primes them to prepare for an imminent attack. Here, however, we show that whitefly-induced tomato plant volatiles prime SA-dependent defenses and suppress JA-dependent defenses, thus rendering neighboring tomato plants more susceptible to whiteflies. Experiments with volatiles from caterpillar-damaged and pathogen-infected plants, as well as with synthetic volatiles, confirm that whiteflies modify the quality of neighboring plants for their offspring via whitefly-inducible plant volatiles.

The potato cyst nematode effector RHA1B is a ubiquitin ligase and uses two distinct mechanisms to suppress plant immune signaling
Kud, Joanna ; Wang, Wenjie ; Gross, Rachel ; Fan, Youhong ; Huang, Li ; Yuan, Yulin ; Gray, Amanda ; Duarte, Aida ; Kuhl, Joseph C. ; Caplan, Allan ; Goverse, Aska ; Liu, Yongsheng ; Dandurand, Louise-Marie ; Xiao, Fangming - \ 2019
PLoS Pathogens 15 (2019)4. - ISSN 1553-7366 - 18 p.
Plant pathogens, such as bacteria, fungi, oomycetes and nematodes, rely on wide range of virulent effectors delivered into host cells to suppress plant immunity. Although phytobacterial effectors have been intensively investigated, little is known about the function of effectors of plant-parasitic nematodes, such as Globodera pallida, a cyst nematode responsible for vast losses in the potato and tomato industries. Here, we demonstrate using in vivo and in vitro ubiquitination assays the potato cyst nematode (Globodera pallida) effector RHA1B is an E3 ubiquitin ligase that employs multiple host plant E2 ubiquitin conjugation enzymes to catalyze ubiquitination. RHA1B was able to suppress effector-triggered immunity (ETI), as manifested by suppression of hypersensitive response (HR) mediated by a broad range of nucleotide-binding leucine-rich repeat (NB-LRR) immune receptors, presumably via E3-dependent degradation of the NB-LRR receptors. RHA1B also blocked the flg22-triggered expression of Acre31 and WRKY22, marker genes of pathogen‐associated molecular pattern (PAMP)‐triggered immunity (PTI), but this did not require the E3 activity of RHA1B. Moreover, transgenic potato overexpressing the RHA1B transgene exhibited enhanced susceptibility to G. pallida. Thus, our data suggest RHA1B facilitates nematode parasitism not only by triggering degradation of NB-LRR immune receptors to block ETI signaling but also by suppressing PTI signaling via an as yet unknown E3-independent mechanism

Arabinoxylans-enriched fractions : From dry fractionation of wheat bran to the investigation on bread baking performance
Zhang, Lu ; Boven, Anneloes van; Mulder, Jorinde ; Grandia, Jeroen ; Chen, Xiao Dong ; Boom, Remko M. ; Schutyser, Maarten A.I. - \ 2019
Journal of Cereal Science 87 (2019). - ISSN 0733-5210 - p. 1 - 8.
Arabinoxylans - Bread baking - Dry fractionation - Valorization

Arabinoxylans- (AX-) enriched fractions were separated from wheat bran by dry fractionation and utilized for fiber fortification in bread. The obtained AX-enriched fractions (AXF) contained 39.2–55.8% arabinoxylans (dry basis). To produce bread with various AX-fortification levels, wheat flour was partially replaced with AXF in the recipe, i.e., 2%, 5% and 10% of flour weight. Results indicate 10% AX fortification led to decreased specific volume, harder and coarser crumb and darker color of bread, while 2% and 5% showed no significant influence. Next, the bread recipe was adjusted based on Farinograph water absorption and the AXF was pre-soaked in water (with or without xylanase) at 40 C for 16 h before dough mixing. The recipe and process adjustment reduced the detrimental effects of a high-level AX-fortification on bread quality. Bread with 10% AXF showed comparable quality properties as the control and its fiber content (11.75% dry basis) was found twice higher than the control (5.48% dry basis). However, usage of xylanase did not further improve the bread quality under tested conditions. In conclusion, this study shows that AX-enriched fractions from wheat bran have valorization potential for application in food.

Transcriptome Analysis of CHO Cell Size Increase During a Fed-Batch Process
Pan, Xiao ; Alsayyari, Abdulaziz A. ; Dalm, Ciska ; Hageman, Jos A. ; Wijffels, René H. ; Martens, Dirk E. - \ 2019
Biotechnology Journal 14 (2019)3. - ISSN 1860-6768
cell cycle - cell size increase - CHO cell culture - mAb production - mTOR - transcriptome analysis
In a Chinese Hamster Ovary (CHO) cell fed-batch process, arrest of cell proliferation and an almost threefold increase in cell size occurred, which is associated with an increase in cell-specific productivity. In this study, transcriptome analysis is performed to identify the molecular mechanisms associated with this. Cell cycle analysis reveals that the cells are arrested mainly in the G0/G1 phase. The cell cycle arrest is associated with significant up-regulation of cyclin-dependent kinases inhibitors (CDKNs) and down-regulation of cyclin-dependent kinases (CDKs) and cyclins. During the cell size increase phase, the gene expression of the upstream pathways of mechanistic target of rapamycin (mTOR), which is related to the extracellular growth factor, cytokine, and amino acid conditions, shows a strongly synchronized pattern to promote the mTOR activity. The downstream genes of mTOR also show a synchronized pattern to stimulate protein translation and lipid synthesis. The results demonstrate that cell cycle inhibition and stimulated mTOR activity at the transcriptome level are related to CHO cell size increase. The cell size increase is related to the extracellular nutrient conditions through a number of cascade pathways, indicating that by rational design of media and feeds, CHO cell size can be manipulated during culture processes, which may further improve cell growth and specific productivity.
Global wheat production with 1.5 and 2.0°C above pre‐industrial warming
Liu, B. ; Martre, P. ; Ewert, F. ; Porter, J.R. ; Challinor, A.J. ; Muller, G. ; Ruane, A.C. ; Waha, K. ; Thorburn, Peter J. ; Aggarwal, P.K. ; Ahmed, M. ; Balkovic, Juraj ; Basso, B. ; Biernath, C. ; Bindi, M. ; Cammarano, D. ; Sanctis, Giacomo De; Dumont, B. ; Espadafor, M. ; Eyshi Rezaei, Ehsan ; Ferrise, Roberto ; Garcia-Vila, M. ; Gayler, S. ; Gao, Y. ; Horan, H. ; Hoogenboom, G. ; Izaurralde, Roberto C. ; Jones, C.D. ; Kassie, Belay T. ; Kersebaum, K.C. ; Klein, C. ; Koehler, A.K. ; Maiorano, Andrea ; Minoli, Sara ; Montesino San Martin, M. ; Kumar, S.N. ; Nendel, C. ; O'Leary, G.J. ; Palosuo, T. ; Priesack, E. ; Ripoche, D. ; Rötter, R.P. ; Semenov, M.A. ; Stockle, Claudio ; Streck, T. ; Supit, I. ; Tao, F. ; Velde, M. van der; Wallach, D. ; Wang, E. ; Webber, H. ; Wolf, J. ; Xiao, L. ; Zhang, Z. ; Zhao, Z. ; Zhu, Y. ; Asseng, S. - \ 2019
Global Change Biology 25 (2019)4. - ISSN 1354-1013 - p. 1428 - 1444.
Efforts to limit global warming to below 2°C in relation to the pre-industrial level are under way, in accordance with the 2015 Paris Agreement. However, most impact research on agriculture to date has focused on impacts of warming >2°C on mean crop yields, and many previous studies did not focus sufficiently on extreme events and yield interannual variability. Here, with the latest climate scenarios from the Half a degree Additional warming, Prognosis and Projected Impacts (HAPPI) project, we evaluated the impacts of the 2015 Paris Agreement range of global warming (1.5°C and 2.0°C warming above the pre-industrial period) on global wheat production and local yield variability. A multi-crop and multi-climate model ensemble over a global network of sites developed by the Agricultural Model Intercomparison and Improvement Project (AgMIP) for Wheat was used to represent major rainfed and irrigated wheat cropping systems. Results show that projected global wheat production will change by -2.3% to 7.0% under the 1.5 °C scenario and -2.4% to 10.5% under the 2.0 °C scenario, compared to a baseline of 1980-2010, when considering changes in local temperature, rainfall and global atmospheric CO2 concentration, but no changes in management or wheat cultivars. The projected impact on wheat production varies spatially; a larger increase is projected for temperate high rainfall regions than for moderate hot low rainfall and irrigated regions. Grain yields in warmer regions are more likely to be reduced than in cooler regions. Despite mostly positive impacts on global average grain yields, the frequency of extremely low yields (bottom 5 percentile of baseline distribution) and yield inter-annual variability will increase under both warming scenarios for some of the hot growing locations, including locations from the second largest global wheat producer -India, which supplies more than 14% of global wheat. The projected global impact of warming <2°C on wheat production are therefore not evenly distributed and will affect regional food security across the globe as well as food prices and trade.
Genetic dissection of flowering time in Brassica rapa responses to temperature and photoperiod
Xiao, Dong ; Shen, Hao Ran ; Zhao, Jian Jun ; Wei, Yan Ping ; Liu, Dong Rang ; Hou, Xi Lin ; Bonnema, Guusje - \ 2019
Plant Science 280 (2019). - ISSN 0168-9452 - p. 110 - 119.
Brassica rapa - FLOWERING LOCUS C (FLC) - Flowering time - Photoperiod - QTL mapping - Temperature

The Brassica rapa (B. rapa) species displays enormous phenotypic diversity, with leafy vegetables, storage root vegetables and oil crops. These different crops all have different flowering time, which determine their growing season and cultivation area. Little is known about the effects of diverse temperature and day-lengths on flowering time QTL associated with FLC paralogues. We phenotyped the flowering time of a doubled haploid population, established from a cross between Yellow sarson and Pak choi under diverse environmental conditions. We identified flowering-time QTL (fQTL) in different photoperiod and temperature regimes in the greenhouse, and studied their colocation with known flowering time genes. As several fQTL colocalized with FLC paralogues, we studied the expression patterns of four FLC paralogues during the course of vernalization in parental lines. Under all environmental conditions tested the major fQTL that mapped to the BrFLC2_A02 locus was detected, however its effect decreased when plants were grown at low temperatures. Another fQTL that mapped to the FLC paralogue, BrFLC5_A03 was also identified under all tested environments, while no fQTL colocated with BrFLC1_A10 or BrFLC3_A03. Furthermore, the vernalization treatment decreased expression of all BrFLC paralogues in the parental lines, and showed the lowest transcript level after 28 days of vernalization. Transcript abundance stayed low after returning the plants for seven days to normal growth temperature. Interestingly, transcript abundance of BrFLC3_A03 and BrFLC5_A03 was repressed much stronger and already reached lowest levels after 14d in the early-flowering type YS-143. This study improves understanding of the effects of daylength and vernalization on flowering time in B. rapa and the role of the different BrFLC paralogues therein.

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