A sensitive real-time PCR assay for the detection of the two Melampsora medusae formae speciales on infected poplar leaves     

Anne-Laure Boutigny  Cécile Guinet  Agathe Vialle  Richard Hamelin  Pascal Frey  Renaud Ioos 《European journal of plant pathology / European Foundation for Plant Pathology》2013,136(3):433-441

Melampsora medusae is a quarantine fungus in the European Union (EU) that causes a damaging leaf rust disease on poplars. Two formae speciales of the pathogen can be distinguished, M. medusae f. sp. deltoidae and M. medusae f. sp. tremuloidae, but the EU plant health directive 2000/29/EC currently in force does not make the distinction between them. EU countries must have the ability to detect and identify rapidly the introduction of these quarantine fungi and to conduct extensive surveys in case of outbreaks. Efficient detection tools are thus needed. In this study, a sensitive real-time PCR assay was developed to detect the presence of M. medusae in poplar leaf samples. A unique primer/hydrolysis probe combination targeting both formae speciales was designed using species-specific polymorphisms observed within the internal transcribed spacer region. An additional primer/hydrolysis probe combination was designed from a region of the 28S rDNA that is highly conserved in the genus Melampsora and used in a separate real-time PCR assay in order to check the quality of the DNA extracted from Melampsora urediniospores. The test developed demonstrated a high sensitivity since it enables the reproducible detection of two M. medusae urediniospore in a mixture of 2 mg of urediniospores (ca 800 000 urediniospores) of other Melampsora species. This new real-time PCR tool should be useful for laboratories in charge of official analyses since it has many advantages over the techniques currently used to monitor this quarantine pathogen in Europe.  相似文献   

Canopy Uptake of 15NH3 by Four Temperate Tree Species and the Interaction with Leaf Properties     

Sandy Adriaenssens  Jeroen Staelens  Karen Wuyts  Shari Van Wittenberghe  Tatiana Wuytack  Kris Verheyen  Pascal Boeckx  Roeland Samson 《Water, air, and soil pollution》2012,223(9):5643-5657

Tree canopies are believed to act as a sink of atmospheric ammonia (NH₃). However, few studies have compared the uptake efficiency of different tree species. This study assessed the uptake of ¹⁵N-labelled NH₃ at 5, 20, 50 and 100?ppb_v by leaves and twigs of potted silver birch, European beech, pedunculate oak and Scots pine saplings in June, August and September 2008. Additionally, foliar uptake of ¹³C-labelled carbon dioxide (¹³CO₂) and leaf stomatal characteristics were determined per species and treatment date and the relation with ¹⁵NH₃ uptake and estimated stomatal ¹⁵NH₃ uptake were assessed. Both ¹⁵NH₃ and ¹³CO₂ uptake were affected by tree species and treatment date, but only ¹⁵NH₃ uptake was influenced by the applied NH₃ concentration. Depending on the treatment date, ¹⁵NH₃ uptake by leaves and twigs was highest at 5 (September), 20 (June) or 50 (August) ppb_v. Birch, beech and oak leaves showed the highest uptake in August, while for pine needles this was in June and, except at 5?ppb_v in June, the ¹⁵NH₃ uptake was always higher for the deciduous species than for pine. For all species except beech ¹³CO₂ uptake was highest in August and on every treatment date the ¹³CO₂ uptake by leaves of deciduous species was significantly higher than by pine needles. Leaf characteristics and ¹³CO₂ uptake did not provide a strong explanation for the observed differences in ¹⁵NH₃ uptake. This study shows that on the short-term a high interspecific variability exists in NH₃ uptake, which depends on the time in the growing season.  相似文献   

A comparative review of fisheries management experiences in the European Union and in other countries worldwide: Iceland,Australia, and New Zealand          下载免费PDF全文

Paul Marchal  Jesper Levring Andersen  Martin Aranda  Mike Fitzpatrick  Leyre Goti  Olivier Guyader  Gunnar Haraldsson  Aaron Hatcher  Troels Jacob Hegland  Pascal Le Floc'h  Claire Macher  Loretta Malvarosa  Christos D Maravelias  Simon Mardle  Arantza Murillas  J Rasmus Nielsen  Rosaria Sabatella  Anthony D M Smith  Kevin Stokes  Thomas Thoegersen  Clara Ulrich 《Fish and Fisheries》2016,17(3):803-824

This study compares the details and performance of fisheries management between the EU and a selection of other countries worldwide: Iceland, New Zealand, and Australia, which are considered in many respects to be among the most advanced in the world in fisheries management. Fisheries management in the EU, Iceland, Australia, and New Zealand has developed following different paths, despite being based on similar instruments and principles. Iceland, Australia, and New Zealand have been at the forefront of developing management practices such as stakeholder involvement, legally binding management targets (Australia, New Zealand), individual transferable quotas, and discard bans (Iceland, New Zealand). The EU has since the beginning of the 21st century taken significant steps to better involve stakeholders and establish quantitative targets through management plans, and a landing obligation is gradually being implemented from 2015 onward. The management of domestic fisheries resources in Australia, New Zealand, and Iceland has, overall, performed better than in the EU, in terms of conservation and economic efficiency. It should, however, be stressed that, compared to Australia, New Zealand, and Iceland, (i) initial over‐capacity was more of an issue in the EU when management measures became legally binding and also that (ii) EU has been progressive in developing common enforcement standards, on stocks shared by sovereign nations. The situation of EU fisheries has substantially improved over the period 2004–2013 in the northeast Atlantic, with fishery status getting close to that in the other jurisdictions, but the lack of recovery for Mediterranean fish stocks remains a concern.  相似文献   

Phosphorus use efficiency of improved faba bean (Vicia faba) varieties in low‐input agro‐ecosystems          下载免费PDF全文

Amsalu Nebiyu  Jan Diels  Pascal Boeckx 《植物养料与土壤学杂志》2016,179(3):347-354

The use of phosphorus (P)‐efficient legumes is a prerequisite for sustainable intensification of low‐input agro‐ecosystems. A study was undertaken in a farmer's field in the tropical highlands of Ethiopia to assess the agronomic performance, P acquisition efficiency (PAE), and P utilization efficiency (PUE) of six improved faba bean varieties (Vicia faba L. var. CS‐20DK, Degaga, Gebelcho, Moti, Obse, Walki) without and with P application. Varieties showed significant variations in PUE, but P application had no significant effect on PUE. Variety Moti demonstrated highest PUE of 272 kg grain kg^?1 P, which was 1.6‐fold higher than the lowest PUE (164 kg grain kg^?1 P) of Gebelcho. PUE was significantly and positively correlated with grain yield (r = 0.542) and negatively correlated with shoot PAE (r = –0.541), indicating that PUE is important for grain yield. The results demonstrate that variations in grain and biomass yield of faba beans were largely due to differences in PUE and not due to PAE. Therefore, we argue that genetic resources of faba bean varieties showing optimal agronomic performance and high PUE in low‐input agro‐ecosystems should be better explored. Introduction of such varieties in low‐input cereal‐based cropping systems could improve and enhance P use efficiency at the system level.  相似文献   

Effects of groundcover management on soil properties, tree physiology, foliar chemistry and growth in a newly established Fraser fir (Abies fraseri [Pursh] Poir) plantation in Michigan, United States of America     

Paligwende Nikiema  Pascal Nzokou  David Rothstein 《New Forests》2012,43(2):213-230

Incorporating cover crops into Christmas tree plantations may potentially improve soil fertility, tree growth and quality and be an alternative to commercial nitrogen (N) fertilizers. However, cover crops may compete with the trees for water and other nutrients than N. This study was carried out to assess whether soil fertility, tree survival and growth could be improved by incorporating leguminous and non-leguminous cover crops into the Fraser fir (Abies fraseri) production system. Dutch white clover (Trifolium pratense), alfalfa (Medicago sativa) and perennial ryegrass (Lolium perenne) were grown in a newly established Fraser fir plantation using two cover crop management practices; no banding (NB) by growing each cover crop throughout the entire plot and banding (B) by creating a 61 cm-wide bare zone centered on the tree rows. A conventionally-managed system (CONV) was used as a control. The cover crop aboveground biomass and N content were assessed. Soil available N (NO₃ ⁻ and NH₄ ⁺) and N mineralization were measured at 0–15, 15–30 and 30–45 cm soil depths. Tree survival, growth, photochemical efficiency of photosystem II (F_v/F_m), branch water potential (Ψ_w) and foliar nutrients were also evaluated. Biomass production was as high as 13.9, 10.2 and 5.9 Mg DM ha⁻¹ year⁻¹ for clover, alfalfa and ryegrass, respectively. Cover cropping increased soil available N by 1.5- and 2.2-fold relative the CONV in the top soil layer in 2007 and 2008, respectively. Tree seedling survival and growth in the B and CONV systems were similar. In contrast, NB treatments resulted in poor seedling survival and growth relative to the B and CONV plots. Plant Ψ_w and F_v/F_m decreased significantly for A. fraseri seedlings on the NB treatments relative to their counterparts on the B and CONV plots. However, cover cropping had marginal effects on foliar nutrients. Cover cropping with banding can be an efficient strategy for maintaining productivity in Fraser fir Christmas plantations.  相似文献   

Model performance of tree height-diameter relationships in the central Congo Basin     

Elizabeth Kearsley  Pieter CJ Moonen  Koen Hufkens  Sebastian Doetterl  Janvier Lisingo  Faustin Boyemba Bosela  Pascal Boeckx  Hans Beeckman  Hans Verbeeck 《Annals of Forest Science》2017,74(1):7

  相似文献   

Plasticity of animal genome architecture unmasked by rapid evolution of a pelagic tunicate     

Denoeud F  Henriet S  Mungpakdee S  Aury JM  Da Silva C  Brinkmann H  Mikhaleva J  Olsen LC  Jubin C  Cañestro C  Bouquet JM  Danks G  Poulain J  Campsteijn C  Adamski M  Cross I  Yadetie F  Muffato M  Louis A  Butcher S  Tsagkogeorga G  Konrad A  Singh S  Jensen MF  Cong EH  Eikeseth-Otteraa H  Noel B  Anthouard V  Porcel BM  Kachouri-Lafond R  Nishino A  Ugolini M  Chourrout P  Nishida H  Aasland R  Huzurbazar S  Westhof E  Delsuc F  Lehrach H  Reinhardt R  Weissenbach J  Roy SW  Artiguenave F  Postlethwait JH  Manak JR  Thompson EM 《Science (New York, N.Y.)》2010,330(6009):1381-1385

Genomes of animals as different as sponges and humans show conservation of global architecture. Here we show that multiple genomic features including transposon diversity, developmental gene repertoire, physical gene order, and intron-exon organization are shattered in the tunicate Oikopleura, belonging to the sister group of vertebrates and retaining chordate morphology. Ancestral architecture of animal genomes can be deeply modified and may therefore be largely nonadaptive. This rapidly evolving animal lineage thus offers unique perspectives on the level of genome plasticity. It also illuminates issues as fundamental as the mechanisms of intron gain.  相似文献   

‘<Emphasis Type="Italic">Candidatus</Emphasis> Phlomobacter fragariae’ and the proteobacterium associated with the low sugar content syndrome of sugar beet are related to bacteria of the arsenophonus clade detected in hemipteran insects     

Pascal Salar  Olivier Sémétey  Jean-Luc Danet  Elisabeth Boudon-Padieu  Xavier Foissac 《European journal of plant pathology / European Foundation for Plant Pathology》2010,126(1):123-127

The phylogeny of ‘Candidatus Phlomobacter fragariae’(Ca. P. fragariae), the agent of the strawberry marginal chlorosis (SMC), and the proteobacterium associated with the low sugar content syndrome of sugar beet (SBRp) is not well understood. The spoT-spoU-recG genetic locus initially characterised by genome walking from a ‘Ca. P. fragariae’ partial spoT sequence was used to determine relatedness of ‘Ca. P. fragariae’ and SBRp with bacteria detected in hemipteran insects. Both plant pathogenic bacteria belong to the same phylogenetic group as bacteria of the arsenophonus clade detected in hemipteran insects. The SBRp is closely related to arsenophonus-like proteobacteria from cixiids and more distantly related to psyllid and delphacid secondary endosymbionts, whereas the relatives of ‘Ca. P. fragariae’ remain to be discovered. No genetic variability was found among isolates of ‘Ca. P. fragariae’ or SBRp. Implications for explaining the emergence of both ‘Ca. P. fragariae’ and SBRp as epidemic plant pathogens are discussed.  相似文献   

Soil organic carbon–stock changes in Flemish grassland soils from 1990 to 2000     

Inge Mestdagh  Steven Sleutel  Peter Lootens  Oswald Van Cleemput  Daan Beheydt  Pascal Boeckx  Stefaan De Neve  George Hofman  Nancy Van Camp  Inge Vande Walle  Roeland Samson  Kris Verheyen  Raoul Lemeur  Lucien Carlier 《植物养料与土壤学杂志》2009,172(1):24-31

Total soil organic‐carbon (SOC) stocks for grassland soils in Flanders (N Belgium) were determined for the Kyoto Protocol reference year 1990 and 2000 in order to investigate whether these soils have been CO₂ sinks or sources during that period. The stocks were calculated by means of detailed SOC datasets, which were available at the community scale for the whole of Flanders. The total SOC stocks for Flemish grassland soils (1 m depth) were estimated at 38 Mt SOC in 1990 and 34 Mt SOC in 2000. The loss of SOC resulted from a decrease in the SOC content of grassland soils (71%) and could also partly (29%) be explained by a decline in grassland area. Significant decreases in %SOC for the 0–6 cm depth layer were found for the 1990s for the coarser‐textured soils with SOC losses ranging between –0.3% and –0.5% over the 10 y period. Specific management practices that disturb the SOC balance such as conversion to temporary grassland and a reduction of animal‐manure application are hypothesized to have contributed to the observed loss of SOC stocks. We furthermore conducted an analysis of uncertainty of the 1990 and 2000 grassland SOC–stocks calculation using Monte Carlo analysis. Probability‐distribution functions were determined for each of the inputs of the SOC‐stock calculation, enabling us to assess the uncertainty on the 1990 and 2000 SOC stocks. The frequency distributions of these simulated stocks both closely approached lognormal distributions, and their 95%‐confidence intervals ranged between 150% and 50% of the calculated mean SOC stock. The standard error on the measured decrease in SOC stocks in Flemish grassland soils during the 1990s was calculated to be 7–8 Tg SOC, which is equivalent to twice this decrease. This clearly shows that large‐scale changes in SOC stocks are uncertainty‐ridden, even when they are based on detailed datasets.  相似文献   

N<Subscript>2</Subscript>O emission from conventional and minimum-tilled soils   总被引：1，自引：0，他引：1  

Daan Beheydt  Pascal Boeckx  Hasan Pervej Ahmed  Oswald Van Cleemput 《Biology and Fertility of Soils》2008,44(6):863-873

In this study, we investigated N₂O emissions from two fields under minimum tillage, cropped with maize (MT maize) and summer oats (MT oats), and a conventionally tilled field cropped with maize (CT maize). Nitrous oxide losses from the MT maize and MT oats fields (5.27 and 3.64 kg N₂O-N ha⁻¹, respectively) were significantly higher than those from the CT maize field (0.27 kg N₂O-N ha⁻¹) over a period of 1 year. The lower moisture content in CT maize (43% water-filled pore space [WFPS] compared to 60–65%) probably caused the difference in total N₂O emissions. Denitrification was found to be the major source of N₂O loss. Emission factors calculated from the MT field data were high (0.04) compared to the CT field (0.001). All data were simulated with the denitrification decomposition model (DNDC). For the CT field, N₂O and N₂O + N₂ emissions were largely overestimated. For the MT fields, there was a better agreement with the total N₂O and N₂O + N₂ emissions, although the N₂O emissions from the MT maize field were underestimated. The simulated N₂O emissions were particularly influenced by fertilization, but several other measured N₂O emission peaks associated with other management practices at higher WFPS were not captured by the model. Several mismatches between simulated and measured \textNH₄⁺ {\text{NH}}_4^ + , \textNO₃^- {\text{NO}}_3^ - and WFPS for all fields were observed. These mismatches together with the insensitivity of the DNDC model for increased N₂O emissions at the management practices different from fertilizer application explain the limited similarity between the simulated and measured N₂O emissions pattern from the MT fields.  相似文献