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Rise and Fall of Phytophthora infestans Resistance to Non-Specific Fungicide in Experimental Populations
No full textBackground: Fungicide resistance is one of the major factors threatening social and ecological sustainability. Many issues associated with the evolutionary processes and mechanisms of fungicide resistance in pathogens remain poorly understood, and better knowledge of these issues through experimentally observing the rise and fall of the resistance is critical for the development of effective management strategies to ensure food security and ecological health. Methods: An experimental evolution approach was used to continuously acclimate a series of Phytophthora infestans populations under different mancozeb conditions for 400 consecutive days. Results: We found that P. infestans developed mancozeb resistance after 200 days of acclimation. This resistance was associated with ABC transporters and endocytic proteins. Potentially due to fitness costs associated with aggressiveness, mancozeb resistance was reversible. And the pathogen exhibited comparable rates of resistance gain during acclimation and resistance loss during the reversal experiment. Conclusions: Our results suggest that this pathogen may also develop resistance to mancozeb. However, this type of resistance may not be persistent, implying the fungicides concerned could be reused in practice. These results provide new insights into the evolution of fungicide resistance and sustainable plant disease chemical management based on the fungicide dose chosen beyond that of potato blight, warranting further study on the resistance target gene
Evaluating urban tree population fitness for a changing climate: Using climatic moisture index
No full textSpecies Distribution Models (SDMs) are essential tools for understanding how species respond to climatic and environmental changes. In this study, we examine the relationship between Climatic Moisture Index (CMI) and leaf water potential (Psi P0) across a variety of tree species to explore how climatic moisture conditions influence tree physiology, particularly in terms of drought tolerance. Using linear regression analysis, we found a statistically significant relationship between CMI and Psi P0, with the direction of the slope indicating how species respond to changes in moisture availability. Species with a positive relationship between CMI and Psi P0 exhibited greater tolerance to fluctuating moisture conditions, while those with a negative relationship showed a higher susceptibility to drought stress. The findings underscore the importance of incorporating climatic factors into conservation and management strategies, particularly for species at risk of water stress under changing climate conditions. This research contributes to a broader understanding of tree physiology, with implications for conservation, restoration, and urban tree selection efforts in the face of global climate change
Identification of 1,6-hexadecanediol and its wax diesters in chloroplasts of Nicotiana benthamiana
No full textMain conclusionExpression of the Arabidopsis phytyl ester synthase PES2 in Nicotiana benthamiana chloroplasts resulted in the accumulation of fatty acid phytyl esters and wax diesters containing the novel alkanediol 1,6-hexadecanediol.AbstractDihydric long-chain alcohols carrying two hydroxyl groups are low abundant in plants and are mostly found in the cutin layer of leaves or the suberin of roots. Transient expression of the phytyl ester synthase PES2 from Arabidopsis thaliana in Nicotiana benthamiana resulted in the accumulation of fatty acid phytyl esters (FAPEs) and of a new lipid class that was identified as wax diesters of 1,6-hexadecanediol, carrying mostly lauric acid (12:0) and myristic acid (14:0) residues. The synthesis of FAPE and wax diesters was only observed when PES2 was targeted to the chloroplasts, in agreement with the finding that both FAPE and wax diesters are chloroplast-localized. The accumulation of wax diesters following PES2 expression demonstrates that the dihydric long-chain alcohol, 1,6-hexadecanediol, is an authentic compound produced in N. benthamiana chloroplasts. 1,6-Hexadecanediol in N. benthamiana is likely synthesized by a chloroplast-localized fatty acid reductase (FAR) in combination with a P450 monooxygenase. PES2-mediated acylation might result in chloroplast-trapping of 1,6-hexadecanediol which is possibly an intermediate in the biosynthesis of functional compounds in leaves or other plant organs
Optimizing small mustelid monitoring: Enclosed camera traps increase detection of the smallest carnivores
No full text1. Land use changes in Europe contribute to the decline of once-abundant species. While these declines are well documented for some species, other, more elusive species could quietly disappear. As a result, small mustelids are believed to be declining across their historical range. Their small size and elusive ecology make small mustelids challenging to monitor and thus remain understudied. In this study, we tested the effectiveness of three camera trap-based methods to monitor common weasel Mustela nivalis, stoat Mustela erminea, and European polecat Mustela putorius. 2. We deployed unenclosed, semi-enclosed, and fully enclosed camera traps in a clustered design incorporating all methods during the fall of 2023 in two extensive agricultural areas in the Netherlands. Using a multi-scale occupancy approach, we assessed (1) how detection probabilities differ among the three camera trap methods for each small mustelid species and (2) how scent-based lures and placement near passages influenced detection probabilities. 3. We found that weasels had the highest detection probability in fully enclosed camera traps placed within clusters containing a scent-based lure. The detection probability of stoats was highest in fully enclosed camera traps, regardless of the presence or absence of lure, as well as in unenclosed camera traps with no lure nearby. Polecats had the highest detection probability in unenclosed camera traps, regardless of lure presence, and in semi-enclosed camera traps without lure nearby. Placing camera traps near passages increased detection probability for all three species. 4. Practical implication: This study advances monitoring protocols for small mustelids, a group facing suspected population declines despite limited data. We highlight different detection probabilities among three mustelid species using various camera-trap methods. Camera trap placement and species-specific use of scent-based lures, beneficial for weasels but not for stoats or polecats, should be considered by researchers and wildlife managers. Combining fully enclosed and unenclosed camera traps enhances species detection and offers broader ecological insights by monitoring other prey and predator mammals as bycatch. Our findings provide practical guidance for large-scale monitoring efforts of small mustelids across Europe
Single-stranded DNA (ssDNA) donor repair templates and CRISPR/Cas9 enable a high-frequency of targeted insertions in potato
No full textHomology-directed repair (HDR) holds great promise for plant genetic engineering but remains challenging due to its inherently low efficiency in gene editing applications. While studies in animal systems suggest that the structure of the donor repair template (DRT) influences HDR efficiency, this parameter remains largely unexplored in plants. In this study, we combined protoplast transfection with next-generation sequencing to analyse the impact of DRT structure on HDR efficiency in potato. A highly efficient ribonucleoprotein (RNP) complex targeting the soluble starch synthase 1 (SS1) gene was used in combination with various DRTs, differing in structural factors such as homology arm (HA) length, strandedness (i.e., ssDNA vs. dsDNA), and sequence orientation in ssDNA donors. Our results indicate that a ssDNA donor in the target orientation outperformed other configurations, achieving a HDR efficiency of 1.12% of the sequencing reads in the pool of protoplasts. Interestingly, HDR efficiency appeared independent of HA length. Notably, a ssDNA donor with HAs as short as 30 nucleotides led to targeted insertions in up to 24.89% of reads on average, but predominantly via alternative imprecise repair pathways, such as microhomology-mediated end joining (MMEJ). This donor structure also consistently yielded the highest HDR and targeted insertion rates at two out of three additional loci tested, offering valuable insights for future genome editing strategies in potato. We further assessed strategies to favour HDR over alternative repair outcomes, including the use of small molecules known to inhibit competing pathways in animal systems, and modifications to DRTs to enhance their availability in the vicinity of the target site. However, these approaches did not improve HDR efficiency. Overall, this study presents an effective platform for rapidly assessing gene editing components in potato and provides insights for achieving high-frequency, targeted insertions of short DNA fragments, especially relevant for efficient knock-in integration in non-coding genomic regions
Antimicrobial resistance and serotype distribution of Salmonella spp. isolated from fresh foods in Cambodia
No full textAims: To determine the Salmonella serotype distribution, antimicrobial resistance profiles, and antimicrobial resistance genes (ARGs) in food samples obtained from local markets in a low-income urban setting and nearby farms in Cambodia.Methods and results: One hundred and thirty-nine Salmonella isolates from various food sources were tested for antibiotic susceptibility using a panel of 12 antibiotics, and 81 selected Salmonella isolates were further sequenced for serotype distribution and ARG identification. The results showed that 71% (99/139) of the isolates exhibited resistance to at least one antibiotic, with 39% (39/99) classified as multidrug-resistant (MDR). The highest resistance was observed against azithromycin (37%), followed by oxytetracycline (35%). A total of 32 serotypes were identified, with the six most common being S. Corvallis (7%), S. Haifa (6%), S. Weltevreden (6%), S. Agona (5%), S. Kentucky (5%), and S. Livingstone (5%). A broad range of ARGs was observed across multiple antibiotic classes, including macrolides, aminoglycosides, tetracyclines, phenicols, fluoroquinolones, sulfonamide–trimethoprim, beta-lactams, and MDR genes.Conclusions: The results highlight the potential role of fresh food products in the widespread dissemination of Salmonella strains resistant to multiple antibiotics
Hållbart växtskydd ur socialt perspektiv
No full textEtt hållbart växtskydd inbegriper både ekologiska, ekonomiska och sociala aspekter. Generellt sett är frågor rörande social hållbarhet det område som är minst utvecklat inom lantbruket, även om intresset ökat kraftigt under senare år. Detsamma gäller för socialt hållbart växtskydd. De växtskyddstrategier som lantbruket använder ska förstås vara bra ur arbetsmiljöperspektiv och lantbrukare ska ha uppskattning för de säkra livsmedel de producerar av hög kvalitet. Men hållbart växtskydd handlar om så mycket mer. Denna rapport är en kunskapssammanställning om vilka sociala aspekter av hållbart växtskydd som är relevanta att beakta. Eftersom forskningen om sociala aspekter av hållbart växtskydd fortfarande är starkt begränsad behandlar även kunskapssammanställningen närliggande aspekter av social hållbarhet inom lantbruket mer generellt. Rapporten fokuserar på svenska förhållanden och förutsättningar.Kunskapssammanställningen lägger även en grund för förslag på indikatorer. Dessa sociala indikatorer syftar till att synliggöra vad ett socialt hållbart växtskydd är och hur vi på ett bättre sätt kan följa utvecklingen över tid. För att strukturera indikatorer på ett lämpligt sätt visar rapporten på betydelsen av att hålla isär social hållbarhet på individnivå, relationell/social nivå och samhällsnivå. Social hållbarhet på individnivå handlar om till exempel kunskaper, attityder och självförtroende. På en mer social nivå – eller relationell nivå – handlar social hållbarhet om föreskrivande normer, nätverk, socialt stöd och samarbeten. På samhällsnivå kompletteras detta med aspekter som till exempel tillgång till rådgivning, marknadskrav och kontrollmyndigheternas agerande, etcetera. Indikatorer bör utvecklas inom de tre nivåerna av social hållbarhet, för att skapa en helhetlig bild av verkligheten och utmaningarna i att nå ett hållbart växtskydd.De indikatorer som rapporten föreslår försöker i möjligaste mån uppfylla ett antal kvalitetskriterier för indikatorer, till exempel enkelhet, betydelse, inkluderande, hanterbarhet, jämförbarhet, kontrollerbara, kontinuitet och (kostnads)effektivitet. Dessa kvalitetskrav är inte alltid möjliga att nå, eftersom det kan vara brist på data eller att det endast är möjligt att mäta indirekta aspekter av socialt hållbart växtskydd. Därför är det av stor vikt att se indikatorerna som varandra kompletterande, vilket resulterat i en indikatorstruktur. Den bygger på tre övergripande kategorier; 1) arbetsmiljöaspekter, 2) kunskapsaspekter, och 3) aspekter kopplade till ekonomiska och sociala relationer. Ambitionen är att strukturen ska spegla den individuella, relationella/sociala och samhälleliga systemnivån, samtidigt som den tydligt kopplar till det sätt på vilket vi idag utvecklat data och underlag för att beskriva social hållbarhet inom lantbruket.De tre övergripande kategorierna i indikatorstrukturen är i sin tur uppdelade i underkategorier. Arbetsmiljöaspekter inbegriper till exempel den fysiska och psykiska arbetsmiljön, de hälso- och miljörisker som uppstår i växtskyddsmedelshanteringen, graden av arbetsglädje och de föreskrivande normer som avgör vad som bedöms som bra eller dåligt, rätt eller fel. I syfte att inte få alltför många indikatorer att arbeta med, men samtidigt landa i en helhetlig beskrivning föreslås följande indikatorer: 1. Arbetsmiljön för lantbrukare och medarbetare. 2. Hälsodata (fysisk, t ex skador, och psykisk, t ex ohälsotal). 3. Hanterings- och miljödata (indirekt hälso- och miljörisker). 4. Attityder till användning, hantering, specifika beteenden, etc. 5. Föreställningar om bra/dåligt växtskydd, inkl hållbarhet, dvs internaliserade normer. 6. Lantbrukarnas mående rent generellt (oberoende av växtskyddsaspekter).Kunskapsaspekter inbegriper både den kunskap och attityder som lantbrukaren besitter, men också tillgången till relevant data, teknik, entreprenörer och möjligheter att testa nya, alternativa arbetssätt. Dessutom krävs en ökad anpassningsförmåga för ett hållbart växtskydd, vilket till exempel kan stödjas genom en löpade och mer riktad behovs- och flaskhalsanalys. Föreslagna indikatorer är: 7. Kunskaper och attityder om hållbart växtskydd hos olika aktörer, framför allt lantbrukare, entreprenörer och rådgivare. 8. Tillgång till rådgivning och rådgivare i alla relevanta delar av landet samt inom relevanta produktionsgrenar. 9. Upplevelse av informationstillgång, dess innehåll, relevans och tillgänglighet, till exempel om datan uppfattas som väl samlad, korrekt och eventuellt om det är ’en dörr in’. 10. Löpande behovs- och flaskhalsanalys av det som berör hållbart växtskydd. 11. Tillgång till entreprenörer och deras kompetens, samt bästa tillgängliga teknik. 12. Tillgång till och stöd i att lära sig mer om, testa och implementera alternativa växtskyddstrategier och arbetssätt.Slutligen har vi de sociala och ekonomiska relationerna där till exempel samhällets attityder och värderingar till växtskydd är av betydelse. Utöver detta är det viktigt att förstå de krav som marknadens aktörer ställer och hur de förhåller sig till till exempel risk för resthalter på fel ställe, men även hur regelverket uppfattas och hur det tillämpas. Förslagna indikatorer är: 13. Allmänhetens uppfattningar om risk och nytta av växtskydd, vilket både handlar om kunskaper och attityder. 14. Marknadsaktörernas uppfattningar om risk och nytta av växtskydd, inklusive hur dessa omsätts i kravspecifikationer och hur dessa samspelar med lantbrukarnas praktik. 15. En bedömning av växtskyddets samhällsbidrag, dvs värdet av produktion av råvaror av hög kvalitet och utan risker. 16. Regelsystemets relevans och effekt, dvs dess ”fit for purpose”, där även frågor om lantbrukarnas förståelse och acceptans för regelverken kan fångas upp. 17. Lantbruksaktörernas tillit och förtroende för samhällets institutioner generellt, men även mer specifikt med avseende på hållbart växtskydd. 18. Mediabilden av växtskydd inom lantbruket.De föreslagna 18 indikatorerna kan i sin tur delas upp i underkategorier med ännu högre upplösning, till exempel genom att man för temat hälsodata fångar upp olika typer av information, både om fysiska skador och psykisk ohälsa, etc. Detta handlar om vilken ambitionsnivå som önskas, men att ta fram åtminstone en specifik mätning för varje indikator är en god början.Rapporten lägger en grund för det fortsatta arbetet, men är på intet sätt fullständig. För varje kategori eller förslag till indikator behöver ytterligare underlag tas fram, både med avseende på exakt hur indikatorn ska formuleras, men även hur datatillgång och mätning ska säkras över tid. Detta är även en fråga om ambitionsnivå och finansiering
Dam-rearing of dairy calves in automatic milking systems
No full textCow-calf contact (CCC) systems offer behavioural and nutritional opportunities for dairy calves that are often restricted or altogether lacking in artificial rearing systems. However, research thus far has focused heavily on the short-term effects of providing CCC, and rarely on contact periods longer than 3 months. The aim of this thesis was to assess the behavioural development and productive performance of dam-reared dairy calves, from birth to the end of their first lactation. Calves were reared in 1 of 5 experimental trials; calves (12–26 per trial) had 3–6 months of full contact with their dams, after which they were weaned, separated, and managed with other youngstock on the research farm. To allow for comparisons of growth, fertility, and first-lactation milk yield, dam-reared heifers were matched on a 1:1 basis to farm-managed, artificially-reared heifers. During the preweaning rearing period, calves housed in a calf-driven system performed fewer but longer suckling bouts as they aged, while this change in suckling behaviours was not observed in calves housed with cow-driven CCC. Allosuckling (i.e., suckling on cows other than the dam) behaviour increased with age for all calves when housed indoors, and was more prevalent with cow-driven CCC. Additionally, dam-reared heifers grew at high rates (1.1–1.4 kg/d) during the contact period. In response to fenceline weaning at both 4 and 6 months of age, calves vocalised, reduced their lying time, increased their locomotor activity, and demonstrated growth checks. These responses were slightly stronger for 4-month-old calves but were overall not associated with time spent in close proximity to dams prior to weaning. Fertility-based measures appeared similar between dam-reared and artificially-reared animals, both prior to first calving and during the first lactation. Dam-reared animals produced less milk and had a poorer persistency during their first lactation; however, milk yield varied between individuals, which may be linked to differences in dam-calf contact management during rearing. This thesis provides evidence that extended periods (i.e., 3–6 months) of dam-calf contact facilitate high growth and expression of motivated suckling behaviours in calves prior to weaning, but may negatively influence long-term productive performance
Developments in proximal crop sensing for precision agriculture
No full textProximal sensing refers to measurements using sensors in close proximity to the object of interest (Adamchuk et al. 2018). Proximal crop sensors are used to collect information about a growing crop and can be mounted on the ground, handheld or borne by vehicles such as tractors or robots. Remote sensing involves the measurement of crop properties often with similar equipment as used in proximal sensing, but from a greater distance, using satellites, airplanes or unmanned aerial vehicles (UAVs, drones). The latter may also be used at short distances. At the other end of the spatial scale, there are sensors that can be used very close to, or in contact with, plant parts. Hence, there is a wide range of different types of sensors and scales on which they are used. Different sensors can also be used in combination, e.g. a proximal sensor can be used to calibrate data collected by remote sensing (Fig. 1).In most cases, crop sensors collect inferential data, i.e. they do not directly measure crop properties of interest but rather produce a metric that can be used to estimate these properties. For example, light in different wavelengths reflected by a crop canopy can be recorded by a crop sensor and translated into useful information for agricultural management using established empirical relationships with e.g. the protein content of the crop.Proximal crop sensors are used to assess and predict a range of different crop conditions, such as nutrient status, incidence of weeds and diseases, and drought stress in plants. The ripening stage of fruits and even number of spikes in a wheat stand can also be determined from digital images. Rapid technological development and access to artificial intelligence and machine learning methods have enabled new applications that were not possible just a few years ago, while still employing sensor techniques that have been used for a number of years