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 global abundance of tree palms
    Muscarella, Robert ; Emilio, Thaise ; Phillips, Oliver L. ; Lewis, Simon L. ; Slik, Ferry ; Baker, William J. ; Couvreur, Thomas L.P. ; Eiserhardt, Wolf L. ; Svenning, Jens Christian ; Affum-Baffoe, Kofi ; Aiba, Shin Ichiro ; Almeida, Everton C. de; Almeida, Samuel S. de; Oliveira, Edmar Almeida de; Álvarez-Dávila, Esteban ; Alves, Luciana F. ; Alvez-Valles, Carlos Mariano ; Carvalho, Fabrício Alvim ; Guarin, Fernando Alzate ; Andrade, Ana ; Aragão, Luis E.O.C. ; Murakami, Alejandro Araujo ; Arroyo, Luzmila ; Ashton, Peter S. ; Corredor, Gerardo A.A. ; Baker, Timothy R. ; Camargo, Plinio Barbosa de; Barlow, Jos ; Bastin, Jean François ; Bengone, Natacha Nssi ; Berenguer, Erika ; Berry, Nicholas ; Blanc, Lilian ; Böhning-Gaese, Katrin ; Bonal, Damien ; Bongers, Frans ; Bradford, Matt ; Brambach, Fabian ; Brearley, Francis Q. ; Brewer, Steven W. ; Camargo, Jose L.C. ; Campbell, David G. ; Castilho, Carolina V. ; Castro, Wendeson ; Catchpole, Damien ; Cerón Martínez, Carlos E. ; Chen, Shengbin ; Chhang, Phourin ; Cho, Percival ; Chutipong, Wanlop ; Clark, Connie ; Collins, Murray ; Comiskey, James A. ; Medina, Massiel Nataly Corrales ; Costa, Flávia R.C. ; Culmsee, Heike ; David-Higuita, Heriberto ; Davidar, Priya ; Aguila-Pasquel, Jhon del; Derroire, Géraldine ; Fiore, Anthony Di; Do, Tran Van; Doucet, Jean Louis ; Dourdain, Aurélie ; Drake, Donald R. ; Ensslin, Andreas ; Erwin, Terry ; Ewango, Corneille E.N. ; Ewers, Robert M. ; Fauset, Sophie ; Feldpausch, Ted R. ; Ferreira, Joice ; Ferreira, Leandro Valle ; Fischer, Markus ; Franklin, Janet ; Fredriksson, Gabriella M. ; Gillespie, Thomas W. ; Gilpin, Martin ; Gonmadje, Christelle ; Gunatilleke, Arachchige Upali Nimal ; Hakeem, Khalid Rehman ; Hall, Jefferson S. ; Hamer, Keith C. ; Harris, David J. ; Harrison, Rhett D. ; Hector, Andrew ; Hemp, Andreas ; Herault, Bruno ; Pizango, Carlos Gabriel Hidalgo ; Honorio Coronado, Eurídice N. ; Hubau, Wannes ; Hussain, Mohammad Shah ; Ibrahim, Faridah Hanum ; Imai, Nobuo ; Joly, Carlos A. ; Joseph, Shijo ; Anitha, K. ; Kartawinata, Kuswata ; Kassi, Justin ; Killeen, Timothy J. ; Kitayama, Kanehiro ; Klitgård, Bente Bang ; Kooyman, Robert ; Labrière, Nicolas ; Larney, Eileen ; Laumonier, Yves ; Laurance, Susan G. ; Laurance, William F. ; Lawes, Michael J. ; Levesley, Aurora ; Lisingo, Janvier ; Lovejoy, Thomas ; Lovett, Jon C. ; Lu, Xinghui ; Lykke, Anne Mette ; Magnusson, William E. ; Mahayani, Ni Putu Diana ; Malhi, Yadvinder ; Mansor, Asyraf ; Peña, Jose Luis Marcelo ; Marimon-Junior, Ben H. ; Marshall, Andrew R. ; Melgaco, Karina ; Bautista, Casimiro Mendoza ; Mihindou, Vianet ; Millet, Jérôme ; Milliken, William ; Mohandass, D. ; Mendoza, Abel Lorenzo Monteagudo ; Mugerwa, Badru ; Nagamasu, Hidetoshi ; Nagy, Laszlo ; Seuaturien, Naret ; Nascimento, Marcelo T. ; Neill, David A. ; Neto, Luiz Menini ; Nilus, Rueben ; Vargas, Mario Percy Núñez ; Nurtjahya, Eddy ; Araújo, R.N.O. de; Onrizal, Onrizal ; Palacios, Walter A. ; Palacios-Ramos, Sonia ; Parren, Marc ; Paudel, Ekananda ; Morandi, Paulo S. ; Pennington, R.T. ; Pickavance, Georgia ; Pipoly, John J. ; Pitman, Nigel C.A. ; Poedjirahajoe, Erny ; Poorter, Lourens ; Poulsen, John R. ; Prasad, P.R.C. ; Prieto, Adriana ; Puyravaud, Jean Philippe ; Qie, Lan ; Quesada, Carlos A. ; Ramírez-Angulo, Hirma ; Razafimahaimodison, Jean Claude ; Reitsma, Jan Meindert ; Requena-Rojas, Edilson J. ; Correa, Zorayda Restrepo ; Rodriguez, Carlos Reynel ; Roopsind, Anand ; Rovero, Francesco ; Rozak, Andes ; Lleras, Agustín Rudas ; Rutishauser, Ervan ; Rutten, Gemma ; Punchi-Manage, Ruwan ; Salomão, Rafael P. ; Sam, Hoang Van; Sarker, Swapan Kumar ; Satdichanh, Manichanh ; Schietti, Juliana ; Schmitt, Christine B. ; Marimon, Beatriz Schwantes ; Senbeta, Feyera ; Nath Sharma, Lila ; Sheil, Douglas ; Sierra, Rodrigo ; Silva-Espejo, Javier E. ; Silveira, Marcos ; Sonké, Bonaventure ; Steininger, Marc K. ; Steinmetz, Robert ; Stévart, Tariq ; Sukumar, Raman ; Sultana, Aisha ; Sunderland, Terry C.H. ; Suresh, Hebbalalu Satyanarayana ; Tang, Jianwei ; Tanner, Edmund ; Steege, Hans ter; Terborgh, John W. ; Theilade, Ida ; Timberlake, Jonathan ; Torres-Lezama, Armando ; Umunay, Peter ; Uriarte, María ; Gamarra, Luis Valenzuela ; Bult, Martin van de; Hout, Peter van der; Martinez, Rodolfo Vasquez ; Vieira, Ima Célia Guimarães ; Vieira, Simone A. ; Vilanova, Emilio ; Cayo, Jeanneth Villalobos ; Wang, Ophelia ; Webb, Campbell O. ; Webb, Edward L. ; White, Lee ; Whitfeld, Timothy J.S. ; Wich, Serge ; Willcock, Simon ; Wiser, Susan K. ; Young, Kenneth R. ; Zakaria, Rahmad ; Zang, Runguo ; Zartman, Charles E. ; Zo-Bi, Irié Casimir ; Balslev, Henrik - \ 2020
    Global Ecology and Biogeography 29 (2020)9. - ISSN 1466-822X - p. 1495 - 1514.
    above-ground biomass - abundance patterns - Arecaceae - local abiotic conditions - Neotropics - pantropical biogeography - tropical rainforest - wood density

    Aim: Palms are an iconic, diverse and often abundant component of tropical ecosystems that provide many ecosystem services. Being monocots, tree palms are evolutionarily, morphologically and physiologically distinct from other trees, and these differences have important consequences for ecosystem services (e.g., carbon sequestration and storage) and in terms of responses to climate change. We quantified global patterns of tree palm relative abundance to help improve understanding of tropical forests and reduce uncertainty about these ecosystems under climate change. Location: Tropical and subtropical moist forests. Time period: Current. Major taxa studied: Palms (Arecaceae). Methods: We assembled a pantropical dataset of 2,548 forest plots (covering 1,191 ha) and quantified tree palm (i.e., ≥10 cm diameter at breast height) abundance relative to co-occurring non-palm trees. We compared the relative abundance of tree palms across biogeographical realms and tested for associations with palaeoclimate stability, current climate, edaphic conditions and metrics of forest structure. Results: On average, the relative abundance of tree palms was more than five times larger between Neotropical locations and other biogeographical realms. Tree palms were absent in most locations outside the Neotropics but present in >80% of Neotropical locations. The relative abundance of tree palms was more strongly associated with local conditions (e.g., higher mean annual precipitation, lower soil fertility, shallower water table and lower plot mean wood density) than metrics of long-term climate stability. Life-form diversity also influenced the patterns; palm assemblages outside the Neotropics comprise many non-tree (e.g., climbing) palms. Finally, we show that tree palms can influence estimates of above-ground biomass, but the magnitude and direction of the effect require additional work. Conclusions: Tree palms are not only quintessentially tropical, but they are also overwhelmingly Neotropical. Future work to understand the contributions of tree palms to biomass estimates and carbon cycling will be particularly crucial in Neotropical forests.

    The Genome of Peronospora belbahrii Reveals High Heterozygosity, a Low Number of Canonical Effectors, and TC-Rich Promoters
    Thines, Marco ; Sharma, Rahul ; Rodenburg, Sander Y.A. ; Gogleva, Anna ; Judelson, Howard S. ; Xia, Xiaojuan ; Hoogen, Johan van den; Kitner, Miloslav ; Klein, Joël ; Neilen, Manon ; Ridder, Dick de; Seidl, Michael F. ; Ackerveken, Guido van den; Govers, Francine ; Schornack, Sebastian ; Studholme, David J. - \ 2020
    Molecular Plant-Microbe Interactions 33 (2020)5. - ISSN 0894-0282 - p. 742 - 753.
    Comparative genomics - Downy mildew - Evolutionary biology - Metabolic pathways - Oomycetes

    Along with Plasmopara destructor, Peronosopora belbahrii has arguably been the economically most important newly emerging downy mildew pathogen of the past two decades. Originating from Africa, it has started devastating basil production throughout the world, most likely due to the distribution of infested seed material. Here, we present the genome of this pathogen and results from comparisons of its genomic features to other oomycetes. The assembly of the nuclear genome was around 35.4 Mbp in length, with an N50 scaffold length of around 248 kbp and an L50 scaffold count of 46. The circular mitochondrial genome consisted of around 40.1 kbp. From the repeat-masked genome, 9,049 protein-coding genes were predicted, out of which 335 were predicted to have extracellular functions, representing the smallest secretome so far found in peronosporalean oomycetes. About 16% of the genome consists of repetitive sequences, and, based on simple sequence repeat regions, we provide a set of microsatellites that could be used for population genetic studies of P. belbahrii. P. belbahrii has undergone a high degree of convergent evolution with other obligate parasitic pathogen groups, reflecting its obligate biotrophic lifestyle. Features of its secretome, signaling networks, and promoters are presented, and some patterns are hypothesized to reflect the high degree of host specificity in Peronospora species. In addition, we suggest the presence of additional virulence factors apart from classical effector classes that are promising candidates for future functional studies.

    Hepatotoxicity of the pesticides imazalil, thiacloprid and clothianidin – Individual and mixture effects in a 28-day study in female Wistar rats
    Alarcan, Jimmy ; Waizenegger, Julia ; Lourdes Marzo Solano, Marize de; Lichtenstein, Dajana ; Luckert, Claudia ; Peijnenburg, Ad ; Stoopen, Geert ; Sharma, Raju Prasad ; Kumar, Vikas ; Marx-Stoelting, Philip ; Lampen, Alfonso ; Braeuning, Albert - \ 2020
    Food and Chemical Toxicology 140 (2020). - ISSN 0278-6915
    EuroMix - Liver hypertrophy - Mixture effects - Pesticides

    Humans are exposed to pesticide residues through various food products. As these residues can occur in mixtures, there is a need to investigate possible mixture effects on human health. Recent exposure studies revealed the preponderance of imazalil, thiacloprid, and clothianidin in food diets. In this study, we assessed their toxicity alone and in binary mixtures in a 28-day gavage study in female Wistar rats. Five dose levels (up to 350 mg/kg bw/day) ranging from a typical toxicological reference value to a clear effect dose were applied. Data show that the liver was a target organ of all pesticides and their mixtures. Increases in liver weight were observed and histopathological examination revealed centrilobular hepatocellular hypertrophy and cytoplasm degeneration for all treatment conditions. No accumulation of hepatic triglycerides was reported. Tissue residue analysis showed altered pesticide residues in the liver and the kidney when being in mixture as compared to the levels of pesticide residues for the single compound treatment, indicating possible toxicokinetic interactions. Overall, all mixtures appeared to follow the additivity concept, even though quantitative analysis was limited for some endpoints due to the semi-quantitative nature of the data, raising no specific concern for the risk assessment of the examined pesticides.

    On the merits and pitfalls of introducing a digital platform to aid conservation management : Volunteer data submission and the mediating role of volunteer coordinators
    Arts, Koen ; Melero, Yolanda ; Webster, Gemma ; Sharma, Nirwan ; Tintarev, Nava ; Tait, Elizabeth ; Mellish, Christopher ; Sripada, Somayajulu ; MacMaster, Ann Marie ; Sutherland, Hollie ; Horrill, Chris ; Lambin, Xavier ; Wal, René van der - \ 2020
    Journal of Environmental Management 265 (2020). - ISSN 0301-4797
    Environmental citizen science - Human-computer interaction - Invasive species control - Technological innovation - Volunteer coordination - Volunteer-based management

    Against a backdrop of accelerating digital innovation in nature conservation and environmental management, a real-world experiment was conducted with the research aims of assessing: 1) the effects of introducing a digital data-entry platform on volunteer data submission; and 2) the extent to which coordinators influence digital platform use by their volunteers. We focussed on a large-scale volunteer-based initiative aimed at eradicating the non-native American mink (Neovison vison) from northern Scotland. This geographically dispersed conservation initiative adopted a digital platform that allowed volunteers to submit records to a central database. We found that the platform had a direct and positive effect on volunteer data submission behaviour, increasing both the number and frequency of submissions. However, our analysis revealed striking differences in coordinator engagement with the platform, which in turn influenced the engagement of volunteers with this centrally introduced digital innovation. As a consequence, the intended organisation-wide rolling out of a digital platform translated into a diversely-implemented innovation, limiting the efficacy of the tool and revealing key challenges for digital innovation in geographically-dispersed conservation initiatives.

    Maternal exposure to mixtures of dienestrol, linuron and flutamide. Part I: Feminization effects on male rat offspring
    Schreiber, Elga ; Garcia, Tània ; González, Neus ; Esplugas, Roser ; Sharma, Raju Prasad ; Torrente, Margarita ; Kumar, Vikas ; Bovee, Toine ; Katsanou, Efrosini S. ; Machera, Kyriaki ; Domingo, José Luis ; Gómez, Mercedes - \ 2020
    Food and Chemical Toxicology 139 (2020). - ISSN 0278-6915
    Dienestrol - Feminization effects - Flutamide - Linuron - Male rats - Mixtures

    Exposure to endocrine-disrupting compounds (EDCs) during pregnancy can result in negative health effects in later generations, including sex changes and feminization. The present study assessed the feminization effects on male offspring rats of three EDCs: Dienestrol (DIES), Linuron (LIN), and Flutamide (FLU). Sexually mature female rats were exposed from gestation day (GD) 6 until postnatal day (PND) 21 to: 0.37, 0.75, 1.5, 3.12 or 6.25 μg/kg/day of DIES, 1.5, 3, 6, 12.5, 25 or 50 mg/kg/day of LIN, 3.5, 6.7, 12.5, 25 or 50 mg/kg/day of FLU, and the following mixtures: FLU + DIES (mg/kg/day+μg/kg/day), 3.5 + 0.37, or 3.5 + 3, 25 + 0.37, or 25 + 3; FLU + LIN (mg/kg/day + mg/kg/day), 3.5 + 12.5, or 25 + 12.5; and DIES + LIN (μg/kg/day + mg/kg/day), 0.37 + 12.5, or 3 + 12.5. Anogenital distance (AGD), nipple retention (NR) and cryptorchidism were evaluated. FLU produced a decrease of AGD, an increase of NR, and an increase of cryptorchidism at the highest dose. None of these three endpoints were significantly affected by LIN or DIES treatments alone. Combinations of FLU + LIN and FLU + DIES increased NR, and decreased AGD, while DIES + LIN did not produce any effects in male pups. Results show that FLU is able to induce feminization in male pups, while binary combinations of LIN and DIES did not modify the effects produced by FLU.

    Dataset for: Presence of seed-borne pest and pathogens on/in the seed produced by farmers in the province of Cotopaxi
    Navarrete Cueva, Israel ; Andrade, Jorge ; Almekinders, Conny ; Struik, Paul - \ 2019
    Kansas State University
    seed degeneration - nematodes - fungi - viruses - seed tubers - seed damaging insects - Potato - Rhizoctonia - Streptomyces scabies - Fusarium - Silver scurf - Powdery scabs - Andean potato weevil - Potato tuber moth - White grub - Wireworm - Flea beetle - PVS - PVY - PVX - PLRV - APMoV - Globodera pallida - Tylenchus spp. - Pratylenchus spp. - Aphelenchoides spp. - Heterodera spp. - Meloidogyne spp. - Paratylenchus Spp. - Saprophytes - Tylenchorhynchus spp.
    Seed degeneration (PSD) threats potato production in developing countries. PSD is defined as the accumulation of pest and pathogens in/on the seed tuber due to the successive cycles of vegetative propagation leading potentially to a yield and quality reduction (Thomas-Sharma et al., 2016; Pl. Path. [vol 65, issue 1]). However, the understanding of PSD in the Andes is deficient due to the limited comprehension of the spatial distribution of potato seed- and soil- borne pests and pathogens. For this reason, 260 farmers´ seed lots and fields were surveyed in the province of Cotopaxi-Ecuador from September to October 2018. The survey was implemented using a stratified sampling design (stratum = Cantons of Latacunga, Pujilí, Salcedo and Saquisilí). The sample size was defined based on the seed replacement rate reported by farmers in a pilot study previously implemented. In each place, farmers kindly provided a sample of (1 to 10) potato seed tubers depending on their willingness. In addition to it, a soil sample was collected from the closest field to the house after farmers provided oral consent. Symptoms and damages on the seed tubers caused by insects and fungi were visually inspected following the methodology suggested by James (1971, [Canadian pl. dis. survey {vol. 51}]) and the photography guide of the main pests and pathogens of the potato crop in Ecuador (Montesdeoca et al., 2013)(Reported in sheet coined "Insects and Fungi"). Virus identification was carried out on plantlets coming from the tubers assessed previously. This was performed by using the kits and the protocol for DAS-ELISA manufactured and suggested by CIP (2007). Six viruses were identified: PVX, PVS, PVY, APLV, PLRV, and APMoV (Reported in sheet coined "Virus"). Forty three soil samples out of the 260 were selected depending on the farmers’ field altitude and landscape location (Reported in sheet coined "nematodes"). These were sent to the laboratory of Plant Protection of the National Agriculture Research Center (INIAP) for nematodes identification. Nematodes were identified according to the methodologies of Oostenbrink (1960) and Fenwick (1940). It is expected that this database contributes to a deeper knowledge about the presence of seed-borne pests and pathogens in the tropical highlands of Ecuador and to design better seed system interventions.;The dataset contains data about presence of seed-borne pest and pathogens on/in the seed produced by farmers in the province of Cotopaxi.
    Farmers' Knowledge and Practices of Potato Bacterial Wilt Management in Ethiopia
    Gobena, Shiferaw Tafesse ; Damtew, E. ; Mierlo, B.C. van; Lie, R. ; Lemaga, B. ; Sharma, Kalpana ; Leeuwis, C. ; Struik, P.C. - \ 2019
    - 1 p.
    Potato (Solanum tuberosum L.) is an increasingly important crop for food and nutrition security in Ethiopia. It is also a vital source of income and more than 3.7 million smallholder farmers are involved in potato production in the country. However, bacterial wilt is currently causing an overwhelming impact on the country's potato production systems, threatening food and nutrition security initiatives.
    A survey of 261 randomly selected smallholder farmers was carried out in three major potato growing districts in the central highlands of Ethiopia to examine farmers' knowledge and management practices of bacterial wilt, and to analyse the role of relevant knowledge in their practices. Considering their different characteristics, three groups of farmers were distinguished: producers of quality declared seed, producers of normal seed and producers of ware potatoes. The results of the study indicated that most farmers (72%) could recognise symptoms of the disease on infected potato plants. However, they had very limited knowledge of the disease including its causal agent, spreading mechanisms, and management methods. All of the farmers were unaware of the causal agent of the disease and there were significant incongruences between scientific explanations and farmers' understanding of the disease. The farmers provided different explanations and confused a causal agent of the disease with various factors, such as water shortage, insects, planting seed potato with high moisture content, and waterlogging. Further, the majority of the farmers (60%) did not know spreading mechanisms of the disease. There was also no statistically significant association between farmers' knowledge of the disease and the category of the farmers.
    Farmers' knowledge of recommended management methods for bacterial wilt was also limited. The study further showed that practices of farmers have striking implication for spreading of the disease instead of controlling it. Previous agricultural extension efforts did not have the desirable effect on farmers' knowledge and practices. Therefore, to bridge the gap between scientific knowledge and farmers' understanding and practices, farmers need to learn about the disease and how to manage it through appropriate learning approaches that foster innovations in their local context.
    Molecular Epidemiology of Ralstonia solanacearum Species Complex Strains Causing Bacterial Wilt of Potato in Uganda
    Abdurahman, Abdulwahab ; Parker, Monica L. ; Kreuze, Jan ; Elphinstone, John G. ; Struik, Paul C. ; Kigundu, Andrew ; Arengo, Esther ; Sharma, Kalpana - \ 2019
    Phytopathology 109 (2019)11. - ISSN 0031-949X - p. 1922 - 1931.
    bacteriology - etiology - population biology

    Bacterial wilt (BW) caused by the Ralstonia solanacearum species complex (RSSC) is a serious threat to potato production in Uganda. However, little is known about the extent of the disease and the type of the pathogen strains involved. A nationwide survey was conducted to study BW prevalence and incidence in potato, and potato tuber and stem samples of potential alternative hosts were collected for pathogen isolation. DNA was extracted from pure cultures for genetic diversity studies. The pathogen was phylotyped by multiplex PCR; then, a subset of isolates was typed at sequevar level. Isolates of the same sequevar were then haplotyped using multilocus tandem repeat sequence typing (TRST) schemes. BW prevalence and incidence in potato farms were 81.4 and 1.7%, respectively. Three RSSC phylotypes were identified, with the majority of the strains belonging to Phylotype II (80%) followed by Phylotype I (18.5%) and III (1.5%). Phylotype I strains belonged to Sequevar 31, and Phylotype II strains belonged to Sequevar 1. Potato-associated Phylotype II Sequevar 1 strains were more diverse (27 TRST haplotypes) than nonpotato Phylotype I (5 TRST haplotypes). Mapping of TRST haplotypes revealed that three TRST haplotypes of Phylotype II Sequevar 1 strains play an important epidemiological role in BW of potato in Uganda being disseminated via latently infected seed.[Formula: see text]

    The genome of Peronospora belbahrii reveals high heterozygosity, a low number of canonical effectors and CT-rich promoters
    Thines, M. ; Sharma, R. ; Rodenburg, Y.A. ; Gogleva, A. ; Judelson, H.S. ; Xia, X. ; Hoogen, D.J. van den; Kitner, M. ; Klein, J. ; Neilen, M. ; Ridder, D. de; Seidl, M.F. ; Ackerveken, G. van den; Govers, F. ; Schornack, S. ; Studholme, D.J. - \ 2019
    BioRxiv
    Along with Plasmopara destructor, Peronosopora belbahrii has arguably been the economically most important newly emerging downy mildew pathogen of the past two decades. Originating from Africa, it has started devastating basil production throughout the world, most likely due to the distribution of infested seed material. Here we present the genome of this pathogen and results from comparisons of its genomic features to other oomycetes. The assembly of the nuclear genome was ca. 35.4 Mbp in length, with an N50 scaffold length of ca. 248 kbp and an L50 scaffold count of 46. The circular mitochondrial genome consisted of ca. 40.1 kbp. From the repeat-masked genome 9049 protein-coding genes were predicted, out of which 335 were predicted to have extracellular functions, representing the smallest secretome so far found in peronosporalean oomycetes. About 16 % of the genome consists of repetitive sequences, and based on simple sequence repeat regions, we provide a set of microsatellites that could be used for population genetic studies of Pe. belbahrii. Peronospora belbahrii has undergone a high degree of convergent evolution, reflecting its obligate biotrophic lifestyle. Features of its secretome, signalling networks, and promoters are presented, and some patterns are hypothesised to reflect the high degree of host specificity in Peronospora species. In addition, we suggest the presence of additional virulence factors apart from classical effector classes that are promising candidates for future functional studies.
    Validation of an ultra-high-performance liquid chromatography-mass spectrometry method for the quantification of cysteinylated aldehydes and application to malt and beer samples
    Bustillo Trueba, P. ; Jaskula-Goiris, B. ; Clippeleer, J. De; Goiris, K. ; Praet, T. ; Sharma, U.K. ; Eycken, E. Van der; Sanders, M.G. ; Vincken, J.P. ; Brabanter, J. De; Rouck, G. De; Aerts, G. ; Cooman, L. De - \ 2019
    Journal of Chromatography. A, Including electrophoresis and other separation methods 1604 (2019). - ISSN 0021-9673
    2-substituted 1,3-thiazolidine-4-carboxylic acids - Beer - Cysteinylated aldehydes - Liquid chromatography-mass spectrometry - Malt - Method validation

    This paper describes the method validation for the simultaneous determination of seven cysteinylated aldehydes, i.e. 2-substituted 1,3-thiazolidines-4-carboxylic acids, using ultra-high-performance liquid chromatography-mass spectrometry (UHPLC–MS). Authentic reference compounds were first synthesized for identification and quantification purposes. Moreover, nuclear magnetic resonance (1H NMR and 13C NMR) was applied for verification of their structure, while ultra-high-performance liquid chromatography–mass spectrometry (UHPLC–MS) was applied for estimation of the purity. The method for quantification of cysteinylated aldehydes in model solutions has been validated according to the criteria and procedures described in international standards. The synthesized compounds were successfully identified via UHPLC–MS by comparing retention time and MS spectra with the commercial reference compounds. Method validation revealed good linearity (R2 > 0.995) over the range of 0.4–2.2 µg/L to approximately 1000 µg/L, depending on the analyte. The limits of quantification varied from 0.9 to 4.3 µg/L depending on the nature of the compound. Furthermore, evaluation of the method showed good accuracy and stability of the standard solutions. Reported chromatographic recoveries ranged from 112 to 120%. Consequently, the currently described method was applied on malt and beer samples. For the first time, quantification of cysteinylated aldehydes was obtained in malt. In contrast, in fresh beers unambiguous identification of these compounds was not achieved.

    Efficiency of insect-proof net tunnels in reducing virus-related seed degeneration in sweet potato
    Ogero, K.O. ; Kreuze, J.F. ; McEwan, M.A. ; Luambano, N.D. ; Bachwenkizi, H. ; Garrett, K.A. ; Andersen, K.F. ; Thomas-Sharma, S. ; Vlugt, R.A.A. van der - \ 2019
    Plant Pathology 68 (2019)8. - ISSN 0032-0862 - p. 1472 - 1480.
    farmer-multiplier - modelling - net tunnels - seed - sweet potato - virus-related degeneration

    Virus-related degeneration constrains production of quality sweet potato seed, especially under open field conditions. Once in the open, virus-indexed seed is prone to virus infection leading to decline in performance. Insect-proof net tunnels have been proven to reduce virus infection under researcher management. However, their effectiveness under farmer-multiplier management is not known. This study investigated the ability of net tunnels to reduce degeneration in sweet potato under farmer-multiplier management. Infection and degeneration were assessed for two cultivars, Kabode and Polista, grown in net tunnels and open fields at two sites with varying virus pressures. There was zero virus incidence at both sites during the first five generations. Sweet potato feathery mottle virus and sweet potato chlorotic stunt virus were present in the last three generations, occurring singly or in combination to form sweet potato virus disease. Virus infection increased successively, with higher incidences recorded at the high virus pressure site. Seed degeneration modelling illustrated that for both varieties, degeneration was reduced by the maintenance of vines under net tunnel conditions. The time series of likely degeneration based on a generic model of yield loss suggested that, under the conditions experienced during the experimental period, infection and losses within the net tunnels would be limited. By comparison, in the open field most of the yield could be lost after a small number of generations without the input of seed with lower disease incidence. Adopting the technology at the farmer-multiplier level can increase availability of clean seed, particularly in high virus pressure areas.

    Twenty-three unsolved problems in hydrology (UPH)–a community perspective
    Blöschl, Günter ; Bierkens, Marc F.P. ; Chambel, Antonio ; Cudennec, Christophe ; Destouni, Georgia ; Fiori, Aldo ; Kirchner, James W. ; McDonnell, Jeffrey J. ; Savenije, Hubert H.G. ; Sivapalan, Murugesu ; Stumpp, Christine ; Toth, Elena ; Volpi, Elena ; Carr, Gemma ; Lupton, Claire ; Salinas, Josè ; Széles, Borbála ; Viglione, Alberto ; Aksoy, Hafzullah ; Allen, Scott T. ; Amin, Anam ; Andréassian, Vazken ; Arheimer, Berit ; Aryal, Santosh K. ; Baker, Victor ; Bardsley, Earl ; Barendrecht, Marlies H. ; Bartosova, Alena ; Batelaan, Okke ; Berghuijs, Wouter R. ; Beven, Keith ; Blume, Theresa ; Bogaard, Thom ; Borges de Amorim, Pablo ; Böttcher, Michael E. ; Boulet, Gilles ; Breinl, Korbinian ; Brilly, Mitja ; Brocca, Luca ; Buytaert, Wouter ; Castellarin, Attilio ; Castelletti, Andrea ; Chen, Xiaohong ; Chen, Yangbo ; Chen, Yuanfang ; Chifflard, Peter ; Claps, Pierluigi ; Clark, Martyn P. ; Collins, Adrian L. ; Croke, Barry ; Dathe, Annette ; David, Paula C. ; Barros, Felipe P.J. de; Rooij, Gerrit de; Baldassarre, Giuliano Di; Driscoll, Jessica M. ; Duethmann, Doris ; Dwivedi, Ravindra ; Eris, Ebru ; Farmer, William H. ; Feiccabrino, James ; Ferguson, Grant ; Ferrari, Ennio ; Ferraris, Stefano ; Fersch, Benjamin ; Finger, David ; Foglia, Laura ; Fowler, Keirnan ; Gartsman, Boris ; Gascoin, Simon ; Gaume, Eric ; Gelfan, Alexander ; Geris, Josie ; Gharari, Shervan ; Gleeson, Tom ; Glendell, Miriam ; Gonzalez Bevacqua, Alena ; González-Dugo, María P. ; Grimaldi, Salvatore ; Gupta, A.B. ; Guse, Björn ; Han, Dawei ; Hannah, David ; Harpold, Adrian ; Haun, Stefan ; Heal, Kate ; Helfricht, Kay ; Herrnegger, Mathew ; Hipsey, Matthew ; Hlaváčiková, Hana ; Hohmann, Clara ; Holko, Ladislav ; Hopkinson, Christopher ; Hrachowitz, Markus ; Illangasekare, Tissa H. ; Inam, Azhar ; Innocente, Camyla ; Istanbulluoglu, Erkan ; Jarihani, Ben ; Kalantari, Zahra ; Kalvans, Andis ; Khanal, Sonu ; Khatami, Sina ; Kiesel, Jens ; Kirkby, Mike ; Knoben, Wouter ; Kochanek, Krzysztof ; Kohnová, Silvia ; Kolechkina, Alla ; Krause, Stefan ; Kreamer, David ; Kreibich, Heidi ; Kunstmann, Harald ; Lange, Holger ; Liberato, Margarida L.R. ; Lindquist, Eric ; Link, Timothy ; Liu, Junguo ; Loucks, Daniel Peter ; Luce, Charles ; Mahé, Gil ; Makarieva, Olga ; Malard, Julien ; Mashtayeva, Shamshagul ; Maskey, Shreedhar ; Mas-Pla, Josep ; Mavrova-Guirguinova, Maria ; Mazzoleni, Maurizio ; Mernild, Sebastian ; Misstear, Bruce Dudley ; Montanari, Alberto ; Müller-Thomy, Hannes ; Nabizadeh, Alireza ; Nardi, Fernando ; Neale, Christopher ; Nesterova, Nataliia ; Nurtaev, Bakhram ; Odongo, Vincent O. ; Panda, Subhabrata ; Pande, Saket ; Pang, Zhonghe ; Papacharalampous, Georgia ; Perrin, Charles ; Pfister, Laurent ; Pimentel, Rafael ; Polo, María J. ; Post, David ; Prieto Sierra, Cristina ; Ramos, Maria Helena ; Renner, Maik ; Reynolds, José Eduardo ; Ridolfi, Elena ; Rigon, Riccardo ; Riva, Monica ; Robertson, David E. ; Rosso, Renzo ; Roy, Tirthankar ; Sá, João H.M. ; Salvadori, Gianfausto ; Sandells, Mel ; Schaefli, Bettina ; Schumann, Andreas ; Scolobig, Anna ; Seibert, Jan ; Servat, Eric ; Shafiei, Mojtaba ; Sharma, Ashish ; Sidibe, Moussa ; Sidle, Roy C. ; Skaugen, Thomas ; Smith, Hugh ; Spiessl, Sabine M. ; Stein, Lina ; Steinsland, Ingelin ; Strasser, Ulrich ; Su, Bob ; Szolgay, Jan ; Tarboton, David ; Tauro, Flavia ; Thirel, Guillaume ; Tian, Fuqiang ; Tong, Rui ; Tussupova, Kamshat ; Tyralis, Hristos ; Uijlenhoet, Remko ; Beek, Rens van; Ent, Ruud J. van der; Ploeg, Martine van der; Loon, Anne F. Van; Meerveld, Ilja van; Nooijen, Ronald van; Oel, Pieter R. van; Vidal, Jean Philippe ; Freyberg, Jana von; Vorogushyn, Sergiy ; Wachniew, Przemyslaw ; Wade, Andrew J. ; Ward, Philip ; Westerberg, Ida K. ; White, Christopher ; Wood, Eric F. ; Woods, Ross ; Xu, Zongxue ; Yilmaz, Koray K. ; Zhang, Yongqiang - \ 2019
    Hydrological Sciences Journal 64 (2019)10. - ISSN 0262-6667 - p. 1141 - 1158.
    hydrology - interdisciplinary - knowledge gaps - research agenda - science questions

    This paper is the outcome of a community initiative to identify major unsolved scientific problems in hydrology motivated by a need for stronger harmonisation of research efforts. The procedure involved a public consultation through online media, followed by two workshops through which a large number of potential science questions were collated, prioritised, and synthesised. In spite of the diversity of the participants (230 scientists in total), the process revealed much about community priorities and the state of our science: a preference for continuity in research questions rather than radical departures or redirections from past and current work. Questions remain focused on the process-based understanding of hydrological variability and causality at all space and time scales. Increased attention to environmental change drives a new emphasis on understanding how change propagates across interfaces within the hydrological system and across disciplinary boundaries. In particular, the expansion of the human footprint raises a new set of questions related to human interactions with nature and water cycle feedbacks in the context of complex water management problems. We hope that this reflection and synthesis of the 23 unsolved problems in hydrology will help guide research efforts for some years to come.

    Towards the development of a biobased economy in Europe and India
    Pant, Deepak ; Misra, Shilpi ; Nizami, Abdul Sattar ; Rehan, Mohammad ; Leeuwen, Rebecca van; Tabacchioni, Silvia ; Goel, Reeta ; Sarma, Priyangshu ; Bakker, Rob ; Sharma, Neeta ; Kwant, Kees ; Diels, Ludo ; Elst, Kathy - \ 2019
    Critical Reviews in Biotechnology 39 (2019)6. - ISSN 0738-8551 - p. 779 - 799.
    Biobased economy - biomass - biorefineries - European Union (EU) - India - value-added products

    India has emerged as a key player with a high potential to develop a biomass and biobased economy due to its large geographic size and the massive amounts of agricultural and non agricultural biomass produced. India has joined hands with Europe to synchronize its efforts to create and facilitate the development of a biobased economy in this country. This paper aims to examine common research and development actions between the European Union (EU) and India to facilitate the development of these biobased economies. As a base, a thorough study has been performed considering the biomass potential and current status of the bioeconomy in both the EU and India based on the distillation of a series of 80 potential recommendations. The recommendations were grouped into four major categories: (1) biomass production, (2) by-products/waste, (3) biorefineries and (4) policy, market, and value-added products. A questionnaire was designed and distributed to key stakeholders belonging to: academia, industry, and policymakers in both India and the EU. A total of 231 responses were received and analyzed, based on the key recommendations made for the essential research and development topics that are of prime importance to develop biobased economies in both the EU and India. The findings of this study suggest recognizing the value-added contributions made by biobased products such as: food, feed, valuable materials and chemicals in both regions. It is important to reduce the overall process costs and minimize the environmental impacts of such a biobased economy.

    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.

    WRF Model Prediction of a Dense Fog Event Occurred During the Winter Fog Experiment (WIFEX)
    Pithani, Prakash ; Ghude, Sachin D. ; Chennu, V.N. ; Kulkarni, Rachana G. ; Steeneveld, Gert Jan ; Sharma, Ashish ; Prabhakaran, Thara ; Chate, D.M. ; Gultepe, Ismail ; Jenamani, R.K. ; Madhavan, Rajeevan - \ 2019
    Pure and Applied Geophysics 176 (2019)4. - ISSN 0033-4553 - p. 1827 - 1846.
    Liquid water content - PBL scheme - vertical level - WIFEX - WRF model

    In this study, the sensitivity of the Weather Research and Forecasting (WRF) model to simulate the life cycle of a dense fog event that occurred on 23–24 January 2016 is evaluated using different model configurations. For the first time, intensive observational periods (IOPs) were made during the unique winter fog experiment (WIFEX) that took place over Delhi, India, where air quality is serious during the winter months. The multiple sensitivity experiments to evaluate the WRF model performance included parameters such as initial model and boundary conditions, vertical resolution in the lower boundary layer (BL), and the planetary BL (PBL) physical parameterizations. In addition, the model sensitivity was tested using various configurations that included domain size and grid resolution. Results showed that simulations with a high number of vertical levels within the lower PBL height (i.e., 10 levels below 300 m) simulated the accurate timing of fog formation, development, and dissipation. On the other hand, simulations with less vertical levels in the PBL captured only the mature physical characteristics of the fog cycle. A comparison of six local PBL schemes showed little variation in the onset of fog life cycle in comparison to observations of visibility. However, comparisons of observations with thermodynamical values such as 2-m temperature and longwave radiation showed poor relationships. Overall, quasi-normal scale elimination (QNSE) and MYNN 2.5 PBL schemes simulated the complete fog life cycle correctly with high liquid water content (LWC; 0.5/0.35 g m −3 ), while other schemes only responded during the mature phase.

    Comparison of Pesticide Exposure in Honey Bees (Hymenoptera : Apidae) and Bumble Bees (Hymenoptera: Apidae): Implications for Risk Assessments
    Gradish, Angela E. ; Steen, Jozef Van Der; Scott-Dupree, Cynthia D. ; Cabrera, Ana R. ; Cutler, G.C. ; Goulson, Dave ; Klein, Olaf ; Lehmann, David M. ; Lückmann, Johannes ; O'Neill, Bridget ; Raine, Nigel E. ; Sharma, Bibek ; Thompson, Helen - \ 2019
    Environmental Entomology 48 (2019)1. - ISSN 0046-225X - p. 12 - 21.
    bumble bee - honey bee - pesticide exposure - risk assessment

    To date, regulatory pesticide risk assessments have relied on the honey bee (Apis mellifera L.) (Hymenoptera: Apidae) as a surrogate test species for estimating the risk of pesticide exposure to all bee species. However, honey bees and non-Apis bees may differ in their susceptibility and exposure to pesticides. In 2017, a workshop ('Pesticide Exposure Assessment Paradigm for Non-Apis Bees') was held to assess if honey bee risk assessment frameworks are reflective of non-Apis bee pesticide exposure. In this article, we summarize the workshop discussions on bumble bees (Bombus spp.). We review the life history and foraging behavior of bumble bees and honey bees and discuss how these traits may influence routes and levels of exposure for both taxa. Overall, the major pesticide exposure routes for bumble bees and honey bees are similar; however, bumble bees face additional exposure routes (direct exposure of foraging queens and exposure of larvae and adults to soil residues). Furthermore, bumble bees may receive comparatively higher pesticide doses via contact or oral exposure. We conclude that honey bee pesticide risk assessments may not always be protective of bumble bees, especially queens, in terms of exposure. Data needed to reliably quantify pesticide exposure for bumble bees (e.g., food consumption rates, soil residue levels) are lacking. Addressing these knowledge gaps will be crucial before bumble bee exposure can be incorporated into the pesticide risk assessment process. Because bumble bees exhibit appreciable interspecific variation in colony and behavioral characteristics, data relevant to pesticide exposure should be generated for multiple species.

    Micro magnetic resonance imaging of murine liver tissue slices on a microfluidic perfusion device
    Sharma, Manvendra ; Patra, Bishnubrata ; Hale, William ; Karsten, Ruby E.H. ; Salentijn, Gert I.J. ; Grajewski, Maciej ; Fuhrer, Erwin ; Zakhurdaeva, Anna ; Mager, Dario ; Korvink, Jan ; Olinga, Peter ; Verpoorte, Elisabeth ; Utz, Marcel - \ 2018
    In: 22nd International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2018. - Chemical and Biological Microsystems Society (22nd International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2018 ) - ISBN 9781510897571 - p. 1722 - 1724.
    Micro-MRI - NMR - PCLS

    Micro-MRI (Magnetic Resonance Imaging) and NMR (Nuclear Magnetic Resonance) spectroscopy are used to image and study metabolic activity of precision-cut liver slices (PCLS) on a microfluidic perfusion device. The imaging experiments were performed under static medium conditions while metabolic activity was monitored under continuous flow of medium. LDH (Lactate dehydrogenase) leakage assay was performed to assess the tissue viability on different days. MR images having ~30 (μm)2 in-plane resolution are recorded. This method could be used to culture and monitor PCLS non-invasively.

    Comparative genomics including the basal pathogen Peronospora belbahrii reveal common evolutionary patterns and the monophyly of downy mildews in a paraphyletic Phytophthora
    Thines, M. ; Sharma, R. ; Rodenburg, Y.A. ; Gogleva, A. ; Judelson, H.S. ; Xia, X. ; Hoogen, D.J. van den; Kitner, M. ; Klein, J. ; Ridder, D. de; Seidl, M.F. ; Ackerveken, G. van den; Govers, F. ; Schornack, S. ; Studholme, D.J. - \ 2018
    IPF
    PRJEB15119 - ERP016822 - Peronospora belbahrii
    The obligate biotrophic downy mildew constitute the most species rich group of oomycetes. So far only handful of genomes of this group of pathogens has been sequenced. Most likely due to low taxon sampling, until now phylogenomic studies with few taxa were in stark contrast to multigene phylogenies with a large number of accessions with respect to the relationships of downy mildews and Phytophthora species. In the current study, we sequenced the whole genome of the economically important basil pathogen Peronospora belbahrii, and performed in-depth comparative genomics and phylogenomics towards clarifying some aspects of downy mildew and Phytophthora evolution.
    Gene expression polymorphism underpins evasion of host immunity in an asexual lineage of the Irish potato famine pathogen
    Pais, Marina ; Yoshida, Kentaro ; Giannakopoulou, Artemis ; Pel, M. ; Cano, Liliana M. ; Oliva, Ricardo F. ; Witek, Kamil ; Lindqvist-Kreuze, Hannele ; Vleeshouwers, V.G.A.A. ; Kamoun, Sophien - \ 2018
    The Sainsbury Laboratory
    asexual reproduction - clonal lineage - Phytophthora infestans - emergent pathogen - evolution - immunity - phenotypic plasticity - expression polymorphism - structural variation - copy number variation - loss of heterozygosity
    Background Outbreaks caused by asexual lineages of fungal and oomycete pathogens are a continuing threat to crops, wild animals and natural ecosystems (Fisher MC, Henk DA, Briggs CJ, Brownstein JS, Madoff LC, McCraw SL, Gurr SJ, Nature 484:186–194, 2012; Kupferschmidt K, Science 337:636–638, 2012). However, the mechanisms underlying genome evolution and phenotypic plasticity in asexual eukaryotic microbes remain poorly understood (Seidl MF, Thomma BP, BioEssays 36:335–345, 2014). Ever since the 19th century Irish famine, the oomycete Phytophthora infestans has caused recurrent outbreaks on potato and tomato crops that have been primarily caused by the successive rise and migration of pandemic asexual lineages (Goodwin SB, Cohen BA, Fry WE, Proc Natl Acad Sci USA 91:11591–11595, 1994; Yoshida K, Burbano HA, Krause J, Thines M, Weigel D, Kamoun S, PLoS Pathog 10:e1004028, 2014; Yoshida K, Schuenemann VJ, Cano LM, Pais M, Mishra B, Sharma R, Lanz C, Martin FN, Kamoun S, Krause J, et al. eLife 2:e00731, 2013; Cooke DEL, Cano LM, Raffaele S, Bain RA, Cooke LR, Etherington GJ, Deahl KL, Farrer RA, Gilroy EM, Goss EM, et al. PLoS Pathog 8:e1002940, 2012). However, the dynamics of genome evolution within these clonal lineages have not been determined. The objective of this study was to use a comparative genomics and transcriptomics approach to determine the molecular mechanisms that underpin phenotypic variation within a clonal lineage of P. infestans. Results Here, we reveal patterns of genomic and gene expression variation within a P. infestans asexual lineage by comparing strains belonging to the South American EC-1 clone that has dominated Andean populations since the 1990s (Yoshida K, Burbano HA, Krause J, Thines M, Weigel D, Kamoun S, PLoS Pathog 10e1004028, 2014; Yoshida K, Schuenemann VJ, Cano LM, Pais M, Mishra B, Sharma R, Lanz C, Martin FN, Kamoun S, Krause J, et al. eLife 2:e00731, 2013; Delgado RA, Monteros-Altamirano AR, Li Y, Visser RGF, van der Lee TAJ, Vosman B, Plant Pathol 62:1081–1088, 2013; Forbes GA, Escobar XC, Ayala CC, Revelo J, Ordonez ME, Fry BA, Doucett K, Fry WE, Phytopathology 87:375–380, 1997; Oyarzun PJ, Pozo A, Ordonez ME, Doucett K, Forbes GA, Phytopathology 88:265–271, 1998). We detected numerous examples of structural variation, nucleotide polymorphisms and loss of heterozygosity within the EC-1 clone. Remarkably, 17 genes are not expressed in one of the two EC-1 isolates despite apparent absence of sequence polymorphisms. Among these, silencing of an effector gene was associated with evasion of disease resistance conferred by a potato immune receptor. Conclusions Our findings highlight the molecular changes underpinning the exceptional genetic and phenotypic plasticity associated with host adaptation in a pandemic clonal lineage of a eukaryotic plant pathogen. We observed that the asexual P. infestans lineage EC-1 can exhibit phenotypic plasticity in the absence of apparent genetic mutations resulting in virulence on a potato carrying the Rpi-vnt1.1 gene. Such variant alleles may be epialleles that arose through epigenetic changes in the underlying genes.
    Data from: Comparative genomics of the nonlegume Parasponia reveals insights into evolution of nitrogen-fixing rhizobium symbioses
    Velzen, R. van; Holmer, R. ; Bu, F. ; Rutten, L.J.J. ; Zeijl, A.L. van; Liu, W. ; Santuari, L. ; Cao, Q. ; Sharma, Trupti ; Shen, D. ; Roswanjaya, Yuda ; Wardhani, T. ; Seifi Kalhor, M. ; Jansen, Joelle ; Hoogen, D.J. van den; Gungor, Berivan ; Hartog, M.V. ; Hontelez, Jan ; Verver, J.W.G. ; Yang, Wei-Cai ; Schijlen, E.G.W.M. ; Repin, Rimi ; Schilthuizen, M. ; Schranz, M.E. ; Heidstra, R. ; Miyata, Kana ; Fedorova, E. ; Kohlen, W. ; Bisseling, A.H.J. ; Smit, S. ; Geurts, R. - \ 2018
    Wageningen University & Research
    comparative genomics - copy number variation - evolution - nitrogen fixation - symbiosis - Parasponia andersonii - Parasponia rigada - Parasponia rugosa - Trema levigata - Trema orientalis - Trema tomentosa
    Nodules harboring nitrogen-fixing rhizobia are a well-known trait of legumes, but nodules also occur in other plant lineages, with rhizobia or the actinomycete Frankia as microsymbiont. It is generally assumed that nodulation evolved independently multiple times. However, molecular-genetic support for this hypothesis is lacking, as the genetic changes underlying nodule evolution remain elusive. We conducted genetic and comparative genomics studies by using Parasponia species (Cannabaceae), the only nonlegumes that can establish nitrogen-fixing nodules with rhizobium. Intergeneric crosses between Parasponia andersonii and its nonnodulating relative Trema tomentosa demonstrated that nodule organogenesis, but not intracellular infection, is a dominant genetic trait. Comparative transcriptomics of P. andersonii and the legume Medicago truncatula revealed utilization of at least 290 orthologous symbiosis genes in nodules. Among these are key genes that, in legumes, are essential for nodulation, including NODULE INCEPTION (NIN) and RHIZOBIUM-DIRECTED POLAR GROWTH (RPG). Comparative analysis of genomes from three Parasponia species and related nonnodulating plant species show evidence of parallel loss in nonnodulating species of putative orthologs of NIN, RPG, and NOD FACTOR PERCEPTION. Parallel loss of these symbiosis genes indicates that these nonnodulating lineages lost the potential to nodulate. Taken together, our results challenge the view that nodulation evolved in parallel and raises the possibility that nodulation originated ∼100 Mya in a common ancestor of all nodulating plant species, but was subsequently lost in many descendant lineages. This will have profound implications for translational approaches aimed at engineering nitrogen-fixing nodules in crop plants
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