Ditylenchus africanus sp. n. from South Africa : a morphological and molecular characterization

Une nouvelle espèce de #Ditylenchus parasite de l'arachide en Afrique du Sud est décrite en se fondant sur des caractères morphologiques et sur ceux provenant du polymorphisme des longueurs des fragments de restriction (RFLPs) de l'ADN ribosomal. La nouvelle espèce, #Ditylenchus africanus n. sp., diffère des deux espèces les plus proches, #D. destructor et #D. myceliophagus, par la combinaison de caractères suivante : RFLPs provenant de sept enzymes de restriction situées sur l'espaceur interne transcrit de rADN, stylet de longueur moyenne et relativement peu robuste (en comparaison de celui de #D. destructor$, longueur de la bursa (exprimée en pourcentage de la longueur de la queue) et longueur des spicules. (Résumé d'auteur

Temporal hydrochemical dynamics of the River Wensum, UK: Observations from long-term high-resolution monitoring (2011–2018)

In 2010, the UK government established the Demonstration Test Catchment (DTC) initiative to evaluate the extent to which on-farm mitigation measures can cost-effectively reduce the impacts of agricultural water pollution on river ecology whilst maintaining food production capacity. A central component of the DTC platform was the establishment of a comprehensive network of automated, web-based sensor technologies to generate high-temporal resolution (30 min) empirical datasets of surface water, groundwater and meteorological parameters over a long period (2011–2018). Utilising 8.9 million water quality measurements generated for the River Wensum, this paper demonstrates how long-term, high-resolution monitoring of hydrochemistry can improve our understanding of the complex temporal dynamics of riverine processes from 30 min to annual timescales. This paper explores the impact of groundwater-surface water interactions on instream pollutant concentrations (principally nitrogen, phosphorus and turbidity) and reveals how varying hydrochemical associations under contrasting flow regimes can elicit important information on the dominant pollution pathways. Furthermore, this paper examines the relationships between agricultural pollutants and precipitation events of varying magnitude, whilst demonstrating how high-resolution data can be utilised to develop conceptual models of hydrochemical processes for contrasting winter and summer seasons. Finally, this paper considers how high-resolution hydrochemical data can be used to increase land manager awareness of environmentally damaging farming operations and encourage the adoption of more water sensitive land management practices

Major agricultural changes required to mitigate phosphorus losses under climate change

Phosphorus losses from land to water will be impacted by climate change and land management for food production, with detrimental impacts on aquatic ecosystems. Here we use a unique combination of methods to evaluate the impact of projected climate change on future phosphorus transfers, and to assess what scale of agricultural change would be needed to mitigate these transfers. We combine novel high-frequency phosphorus flux data from three representative catchments across the UK, a new high-spatial resolution climate model, uncertainty estimates from an ensemble of future climate simulations, two phosphorus transfer models of contrasting complexity and a simplified representation of the potential intensification of agriculture based on expert elicitation from land managers. We show that the effect of climate change on average winter phosphorus loads (predicted increase up to 30% by 2050s) will be limited only by large-scale agricultural changes (e.g., 20–80% reduction in phosphorus inputs)

The <i>Pratylenchus penetrans</i> transcriptome as a source for the development of alternative control strategies:mining for putative genes involved in parasitism and evaluation of <i>in planta</i> RNAi

The root lesion nematode Pratylenchus penetrans is considered one of the most economically important species within the genus. Host range studies have shown that nearly 400 plant species can be parasitized by this species. To obtain insight into the transcriptome of this migratory plant-parasitic nematode, we used Illumina mRNA sequencing analysis of a mixed population, as well as nematode reads detected in infected soybean roots 3 and 7 days after nematode infection. Over 140 million paired end reads were obtained for this species, and de novo assembly resulted in a total of 23,715 transcripts. Homology searches showed significant hit matches to 58% of the total number of transcripts using different protein and EST databases. In general, the transcriptome of P. penetrans follows common features reported for other root lesion nematode species. We also explored the efficacy of RNAi, delivered from the host, as a strategy to control P. penetrans, by targeted knock-down of selected nematode genes. Different comparisons were performed to identify putative nematode genes with a role in parasitism, resulting in the identification of transcripts with similarities to other nematode parasitism genes. Focusing on the predicted nematode secreted proteins found in this transcriptome, we observed specific members to be up-regulated at the early time points of infection. In the present study, we observed an enrichment of predicted secreted proteins along the early time points of parasitism by this species, with a significant number being pioneer candidate genes. A representative set of genes examined using RT-PCR confirms their expression during the host infection. The expression patterns of the different candidate genes raise the possibility that they might be involved in critical steps of P. penetrans parasitism. This analysis sheds light on the transcriptional changes that accompany plant infection by P. penetrans, and will aid in identifying potential gene targets for selection and use to design effective control strategies against root lesion nematodes

Using word clouds to present farmers' perceptions of advisory services on pollution mitigation measures

Advice delivery is one mechanism that can be used to encourage the uptake of water pollution mitigation measures amongst the farming community, but determining who is best placed to effectively provide advice and increase adoption creates a challenge for policy-makers. Through in-depth interviews, this research investigates the perspectives of both farmers and farm advisers on the delivery of water pollution mitigation advice in three agriculturally contrasting areas of England. A novel approach using word clouds as a visual comparative tool for qualitative data is presented to demonstrate a transferable method for disseminating research findings to a wider audience outside of academia. Results from the interviews indicate differences across the regions, and that contrasts exist between farmers and advisers' perceptions. This suggests it is important to assess both perspectives when designing effective advice delivery mechanisms and for policy-makers to consider who is most appropriate to effectively deliver farm advice

The roles of farm advisors in the uptake of measures for the mitigation of diffuse water pollution

Governments face increasing pressure to implement effective policy to reduce diffuse water pollution from agriculture (DWPA). Various strategies and combinations of policy mechanisms have been adopted by different countries to change farmer behaviours with varying degrees of success. This paper focuses on the use of advice delivery to farmers as a mechanism to encourage uptake of DWPA mitigation measures on farms in England.Farm advisory services in England have dramatically changed over recent years, with concerns that the sector has become fragmented due to many organisations and businesses offering advice. This paper studies the role of various farm advisors and organisations providing one-to-one advice by interviewing 81 farm advisors in three agriculturally contrasting regions of England: East Anglia, the North West and South West. Objectives were to assess: which DWPA mitigation measures are being recommended by different advisors? How do recommendations differ between sources of advice and is there any conflict? And which mechanisms do advisors use to influence uptake of advice?Results from the interviews indicate that the advice delivered and the mechanisms used to influence uptake of advice vary between organisations and some advisors do indeed have particular roles within the farm advisory sector. Policy makers therefore need to consider not only what mitigation measures should be encouraged, but also which organisations and advisors are best placed to deliver on the ground advice to farmers. There is also scope to incorporate understandings of farm advice provision into catchment management plans to aid effectiveness of future agri-environmental policy

Study of surfactant-siloxane interfaces in spray-dried mesoporous silica-based spheres

We have undertaken the synthesis of spray-dried mesoporous silica-based micrometric spheres using various synthetic procedures. In this article, we focus on the relationship between textural properties and small organic groups bound to the siloxane network (residual alkoxy groups or added functions). A correlation has been found between the characteristic XRD distance and the quantity of Si-bound organic groups (measured by 1H solid-state NMR) located at the surfactantesiloxane interface which demonstrates the effect of these organic groups. However, under certain circumstances, Si-bound organic groups can be trapped inside the siloxane network. They have then a different effect on the texture, and are less accessible for further applications. In that sense, this study can also be used in a predictive way for the synthesis of mesoporous spheres with surfaces of functionalised channel