查看更多>>摘要：Abstract Chicken gut microbiota–host interactions play essential roles in the productivity and health of chickens. Deciphering the microbial composition and its functions are crucial for understanding the roles of gut microbiota within chickens. Although there are some research studies focusing on different chicken microbiota, none of them have considered medium‐slow growing chicken as a model host. Here, the microbial composition of the faeces of medium‐slow growing chicken, grown in an organic farming system, has been elucidated through 16S rRNA gene amplicon‐based metagenomics. We found a diverse microbiota that does not present major shifts during the first 4?weeks of the animal's life, although the abundance of only 2 OTUs (Lactobacillus and Bacteroides) increase during this time. Lactobacillus appear to govern the bacterial composition, followed distantly by Clostridiales (mainly Faecalibacterium, Ruminococcus and unidentified genera from the families Peptostreptococaceae and Ruminococcaceae) and Bacteroidales (Bacteroides and Parabacteroides). The roles of Redbro faeces microbiota have been revealed through in silico functional predictions. We found that Lactobacillus members may play relevant roles within its host and seem to highly influence the metabolism of fructose and mannose among other relevant functions.
José Martín JáureguiJonathan J. OjedaGermán Darío BeroneFernando Alfredo Lattanzi...
11页
查看更多>>摘要：Abstract Argentina grows the second‐largest area of lucerne in the world. Despite its importance, a yield gap exists between potential and measured yields, but factors contributing to it are still unclear. This study aimed to identify management factors and research needs to reduce the lucerne yield gap to improve the livestock systems in this region. We used meteorological data coupled with lucerne crop modelling and measured yields from the National Lucerne Cultivar Evaluation Network (NLCEN) to quantify the lucerne yield gap in nine sites located within the Argentinian Pampas (between parallels 30–45°S and meridians 58–65°W) and three sites outside the Pampas. Specifically, we used the model developed by McCall & Bishop‐Hurley (2003), adapted and calibrated for lucerne in Argentina by Berone et al. (2017) to estimate the potential yield (PY) for 12 locations (three irrigated and nine rainfed), and compared those results with measured yields from the NLCEN to calculate yield gaps. We found the average available photosynthetic active radiation (PAR) and temperatures were sufficient to achieve 21.5?±?3.7?t dry matter (DM) ha?1?yr?1 under rainfed conditions (environments with mean annual rainfall from 400 to 1,200?mm). However, the average measured yield from the NLCEN was 16.8?±?2.4?t DM ha?1?yr?1 (a 22% gap). Potential yields ranged between 10 and 25?t DM ha?1?yr?1 under rainfed conditions and between 25 and 39?t DM ha?1?yr?1 for irrigated crops. As latitude increased rainfed locations had lower yields, while irrigated locations had higher yields. Adding irrigation was predicted to increase yields to 35.4?±?2.0?t DM ha?1?yr?1 (a 53% gap) in rainfed sites. For irrigated locations, the gap was smaller (27.3?±?3.5 vs 32.4?±?2.2?t DM ha?1?yr?1 for measured vs potential yield, respectively), and most likely linked to nutrient deficits. Also, current grazing management was estimated to achieve approximately 50% less grazing efficiency than optimal grazing management. Our results demonstrated that the livestock industry can potentially increase animal production under current environmental conditions. The four main adjustments to achieve this are increased use of irrigation, increased use of fertilisers, earlier commencement of grazing in spring and increased stocking rates. The costs of irrigation, fertilisers and grazing management are envisaged to be small compared with potential increases in incomes and thus profitability available to beef and dairy farmers using lucerne as a major feed source in Argentina.
查看更多>>摘要：Abstract Clubroot caused by Plasmodiophora brassicae is one of the major diseases on cruciferous crops. This disease has been a problem all over the world and led to serious economic losses in cruciferous crop production. The improvement of clubroot management is dependent on the effectiveness of bioassays on pathogenicity or plant resistance. P. brassicae resting spore inoculum prepared from clubroot tissues was widely used in bioassays. Traditionally, resting spore concentration was measured by visual counting with a haemocytometer; however, this method is time‐consuming, labour intensive and with poor repeatability due to the tiny size of resting spores. In this study, we established a turbidimetric method to measure P. brassicae resting spore concentration of the inoculum. A regression curve was generated by plotting optical density of gradiently diluted resting spore suspension against the corresponding resting spore concentrations, which resulted in a logarithmic regression equation. This method was validated and proved to be robust and effective in determining resting spore concentration of different samples, and was further confirmed by bioassay of infection and clubroot development. In conclusion, we established a standard protocol to prepare P. brassicae inoculum and provided an effective method for resting spore concentration determination. The results of this study can be widely used in research activities on clubroot sustainable management when an effective assessment of P. brassicae biomass is needed.
查看更多>>摘要：Abstract RNA interference (RNAi) has great potential in functional genomics research and pest control. Gene silencing and phenotypes ranging from appetite loss to death have been observed after larvae fed on leaves of double‐stranded RNA (dsRNA)‐expressing transgenic plants harbouring specific genes from the target insect. In this study, transgenic poplar plants expressing CYP6B53 dsRNA from Lymantria dispar were generated via Agrobacterium‐mediated transformation to control this pest. The CYP6B53 was successfully integrated into the poplar genome by reverse transcription PCR (RT‐PCR) and dsCYP6B53 expression confirmation. Expression was significantly down‐regulated at the transcription level after L. dispar larvae feeding on leaves of the transgenic plants. Meanwhile, CYP6B53 transcription levels in the larvae decreased by 25.31–88.53% compared with those reared on transgenic poplar expressing green fluorescent protein (GFP) dsRNA. A bioassay further revealed that transgenic plants expressing dsCYP6B53 not only inhibited larval feeding but also delayed overall growth. In summary, Poplar plants harbouring CYP6B53 dsRNA resulted in suppression of CYP6B53 expression in L. dispar larvae, impairing development, and providing a novel alternative for pest control.
查看更多>>摘要：Abstract The effectiveness of ground‐based applications of Bacillus thuringiensis var. kurstaki (Btk) for controlling oak processionary moth (OPM) was evaluated by comparing the numbers of larval nests on treated and untreated oak trees in Richmond Park, in west London, UK. A total of 760 oak trees (Quercus robur) were monitored over a period of 4?years from 2014 to 2017, and the effects of current treatment and previous treatment history on nest numbers were analysed using general linear mixed models. Two applications of Btk applied 7–10?days apart in the spring, just after egg hatch, reduced the numbers of larval nests by 86–94%. In 2015, the effectiveness of treatment decreased as tree height increased, whereas in 2016 and 2017 nest numbers were reduced by a similar percentage across all tree height classes. The effects of treatment were relatively short‐lived, because at the scale at which the insecticide applications were carried out, trees were re‐colonised rapidly by adult OPM flying in from the surrounding area. Consequently, nest numbers generally returned to pre‐treatment densities within 1–2?years.
Maissa Ben‐JabeurZoubeir ChamekhSalma JallouliSawsen Ayadi...
12页
查看更多>>摘要：Abstract Abiotic stresses such as drought and heat constitute one of the major constraints to global crop production, and climate change will worsen the scenario. There is growing interest in investigating the application of biostimulants to palliate yield losses due to the impact of drought and heat stress. This study focuses on assessing the impact of coating seeds with either thyme essential oil or Paraburkholderia phytofirmans PsJN strain on agronomic performance of durum wheat subjected to contrasting levels of irrigation. For this aim, the Tunisian durum wheat genotype Karim was cultivated in a field experiment in a semi‐arid climate, with two supplemental irrigation levels (SI): moderate drought stress (100% SI) and severe drought stress (50% SI). The impact of the seed coating technique was assessed on grain yield (GY) and its agronomic components (spikes/m2, straw yield [SY], 1,000 kernel weight [TKW] and the harvest index [HI]) across two consecutive crop seasons; 2015–16 and 2016–17. In addition, the effect on leaf nitrogen and carbon isotope composition (δ15N, δ13C) and nitrogen and carbon contents of leaves at grain filling was also assessed in the 2016–17 season. The two seed coating treatments (SCTs) enhanced GY, SY, spikes/m2, TKW and HI under both moderate stress (100% SI) and severe stress (50% SI). The positive effect of the SCTs on GY and agronomic yield components was more marked under the combined heat–water stress conditions of the first season (2015–16). In general, thyme oil enhanced vegetative growth, tillering and tiller fertility, while, PsJN had a positive effect, more centred on the grain filling stage. Under moderate stress, both SCTs decreased δ15N and δ13C at grain filling and straw N content at harvest, illustrating a better carbon and nitrogen uptake and mobilisation. Under severe water stress, both SCTs induced higher leaf total N, and lower δ13C, and leaf total C at grain filling. The effect on physiological traits and carbon and nitrogen metabolism is discussed. The findings emphasise a practical implication of these biostimulants.
查看更多>>摘要：Abstract Science–farming partnerships can improve our understanding of how land management behaviours sustain or enhance life‐sustaining soil ecosystems. However, it remains a challenge to establish partnerships between researchers and practitioners that complement the ways in which farmers acquire and value knowledge and can also advance soil science. A pilot study was conducted to explore these issues in relation to earthworm monitoring. It showed that farmers were interested in comparing their field results to research experiments to inform their decision‐making. Social media was used to support farmers' earthworm monitoring schemes, with a concomitant sampling of research experiments to create capacity for shared learning. Constructive feedback from the scientific community was sought using an online questionnaire. An Autumn 2018 survey generated 152 field analyses from farmlands in England, and 48% of participants' fields and the research experiment showed no evidence for earthworms being widespread and/or the presence of all three ecological groups of earthworms. A Spring 2019 survey generated earthworm population data from farmland soils around the world, amassing 11,464 earthworms assessed over 2,200?ha in the UK. A total of 12 scientists (from 30 questionnaire invitations) volunteered their time and expertise to support the survey. Conclusions helped to prioritise future improvements in earthworm monitoring, which should include photographs of earthworms for verification of the data, long‐term monitoring and integration with soil properties. Most (83%) perceived this earthworm survey would likely improve farmland soil health and so would recommend its use in the UK. The survey is being independently taken forward and used as a metric by both private and public stakeholders, demonstrating authentic knowledge transfer in soil science.
查看更多>>摘要：Abstract Application of organic fertilisers is beneficial to the quality and yield of crops. Myo‐inositol phosphate is an abundant form of organic phosphorus (Po) in organic manure and soil, which could release phosphate (Pi) and likely be absorbed by plant after it was hydrolysed by phytase. However, whether plant roots respond to organic fertiliser to adapt myo‐inositol phosphates utilisation is not clear. Experiments were carried out to investigate the responses of phytase gene expression and enzyme activity, as well as root architecture to organic fertiliser application. The results showed that Cow‐dung‐based organic fertiliser contains 2.30?g/kg soluble P, including 0.08?g/kg myo‐inositol phosphates P. Organic acid addition promotes myo‐inositol phosphates solubility in organic fertiliser. Partial substitution of Pi with P from organic fertiliser upregulated the expression of ClaPhy1, ClaPhy2 and ClaPhy3 in roots, while it did not change ClaPHT1 family expression. Root phytase activity increased markedly at 25–30% organic fertiliser substitution rates. P concentration in watermelon leaves increased when 25% Pi was substituted with P from organic fertiliser. Organic fertiliser supply also promoted lateral root density and root hair length. In conclusion, organic fertiliser contains soluble myo‐inositol phosphates, more of which was dissolved by organic acids secreted from plant roots. Substitution of Pi with P from organic fertiliser upregulated ClaPhy genes expression and enhanced root phytase activity, as well as increased lateral root number and root hair density. Myo‐inositol phosphates hydrolysis and root morphology adaptation facilitate watermelon utilisation of myo‐inositol phosphates P in organic fertiliser. This study provides evidence to advance utilisation of myo‐inositol phosphates P from organic fertiliser by plant roots via up‐regulation of ClaPhy expression which increased phytase secretion, and optimised root morphology.
NSTL
Wiley