Pest Management Science

BACKGROUNDThe soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is a pest of soybean in North America that can cause significant yield loss when outbreaks are not managed. Current management tactics primarily rely on inexpensive pyrethroids, but the sustainability of this option is threatened by insecticide-resistance in A. glycines populations across the Upper-Midwest United States. Field-evolved resistance is associated with mutations in the voltage-gated sodium channel subunit h1 (vgsc-h1) gene. RESULTSFour double-stranded RNA (dsRNA) molecules, each matching the sequence of a vgsc-h1 transcript variant ("Specific dsRNAs"), were topically applied to aphids with a genotype carrying the corresponding allele. The mortality of pyrethroid resistant aphids exposed to a Specific dsRNA increased in a dose-dependent manner when applied alone or with a constant concentration of lambda-cyhalothrin, plateauing at 1000 ng ul-1. Synergism was detected between two of four combinations of the Specific dsRNAs and lambda-cyhalothrin. These results were mirrored by the topical application of a single dsRNA with the consensus sequence of all vgsc-h1 variants ("Combined dsRNA"). Mortality was consistently higher in aphids treated with either Specific dsRNA or the Combined dsRNA, alone or with lambda-cyhalothrin, compared to insecticide alone. The number of nymphs produced per female treated with the Specific or Combined dsRNA alone decreased significantly compared to untreated controls. CONCLUSIONThis study demonstrates that the topical application of dsRNAs targeting vgsc-h1 increases the susceptibility and reduces the reproductive capacity of pyrethroid resistant soybean aphids, potentially providing a novel tool for the management of insecticide-resistant aphid populations.

Pesticides remain indispensable for global food security, yet their use must be reconciled with the preservation of biodiversity. Despite advances in developing safer pesticides, their sublethal effects and synergistic potential with co-formulants in tank-mixtures, including inert spray adjuvants, often remain poorly understood in beneficial insects like bees. In this study, we assessed the effects of acute oral exposure to field-realistic doses of SilwetTM L-77 (an organosilicone adjuvant; 0.1-2.5%), acetamiprid (a cyano-substituted neonicotinoid; 6-150 ng/bee), and sulfoxaflor (a sulfoximine; 3-27 ng/bee) on gustatory responsiveness, associative olfactory learning, and short-term memory retention in honeybees (Apis mellifera L.). While we found no significant evidence of interaction effects at the exposure concentrations tested, the highest doses of SilwetTM L-77 and sulfoxaflor alone significantly reduced gustatory responsiveness. Furthermore, all three agrochemicals alone weakly affected associative learning without impacting memory retention. Although adjuvant-insecticide mixtures did not synergistically impair bee cognition, these adjuvants can impact sensory perception. Moving beyond mortality-based assessments and including sensory-cognitive thresholds is essential for a more holistic understanding of pollinator health.

Drosophila suzukii (Matsumura, 1931, Diptera: Drosophilidae) is a globally invasive pest of soft-skinned fruits that is currently controlled largely through the use of broad-spectrum insecticides. Increasing resistance to pesticides and regulatory pressures have motivated the development of genetic control strategies. We previously developed a CRISPR/Cas9-based homing gene drive targeting the coding sequence of the female-specific exon of the sex-determination gene doublesex, achieving highly efficient inheritance (94-99%) in both male and female germlines. A major limitation of homing gene drives is the formation of resistant alleles that evade cleavage yet retain gene function. Multiplexing guide RNAs (gRNAs) could reduce the formation of such functional resistance alleles. Here, we generated and tested homing constructs expressing one, two, or three gRNAs targeting different regions of the female-specific exon of doublesex, including a splice-junction target site. A single gRNA targeting the splice junction supported high inheritance in males but showed reduced efficiency in females. Combining this gRNA with a coding sequence-targeting guide further reduced drive efficiency, particularly in the female germline. Constructs expressing two gRNAs performed similarly whether guides were linked by transfer RNA (tRNA) sequences or expressed from independent promoters. Constructs expressing three gRNAs using tRNA processing showed consistently low drive inheritance in both sexes, likely a consequence of reduced cleavage efficiency due to inefficient gRNA production. Inheritance was significantly higher in male than female germlines for several constructs, indicating that germline context strongly influences drive performance. Our findings highlight that the approach used for multi-gRNA expression, target site choice and sex-specific germline environments can impact gene drive efficiency, and emphasize the need to optimize construct design within the biological context of the target species.

Plant-parasitic nematodes (PPNs) are among the most destructive agricultural pests worldwide, causing significant economic losses across diverse cropping systems. Soil fumigation, the most common management strategy, is costly, detrimental to soil health, and increasingly restricted due to environmental and regulatory concerns. As a result, there is a critical need for alternative, sustainable approaches for PPN control. Solanum sisymbriifolium is resistant to several Meloidogyne species and represents a promising source of natural nematicidal compounds. In this study, we evaluated the effects of S. sisymbriifolium extracts on Meloidogyne chitwoodi and M. hapla, two economically important nematodes. Compounds were extracted using solvents of increasing polarity and then reconstituted in water. The water-solubilized extracts were then used in bioassays to assess their effects on nematode egg hatching, egg viability, and second-stage juvenile (J2) survival. Egg hatching and J2 viability of both Meloidogyne species were consistently affected by compounds in the 1-butanol fraction. Further characterization of these compounds may enable the development of novel, environmentally sustainable alternatives to conventional nematode management strategies.

Evidence of negative health and environmental effects of glyphosate-based herbicides (GBHs) has led to marketing of glyphosate-free formulations. A frequent glyphosate replacement is pelargonic acid, which is rapidly degraded, leading to claims of greater safety and less environmentally damaging than GBHs. However, toxicity of commercial pelargonic acid formulations containing several co-formulants have not been determined. Using Roundup NL, a representative pelargonic acid-based herbicide, we undertook tissue culture cell assays measuring viability, plasma membrane integrity, DNA damage, and activation of stress-response pathways. In human hepatoma HepG2 cells, Roundup NL was more cytotoxic than pelargonic acid, and more toxic than the GBH Roundup ProBio and glyphosate as shown by reduced viability underpinned by plasma membrane damage. Pelargonic acid and Roundup NL did not induce oxidative stress. However, comet assays revealed that pelargonic acid but not Roundup NL caused a modest but significant increase in DNA damage at sub-cytotoxic concentrations. The murine embryonic stem cell-based ToxTracker system confirmed Roundup NL as not directly genotoxic but triggered oxidative stress and protein damage (ER stress, impaired proteostasis) indicating cell and assay dependency of oxidative stress pathway activation. Our results suggest that exposure to pelargonic acid-based herbicides constitutes a health hazard and that co-formulants present in Roundup NL contribute substantially to its overall toxicity.

The tomato leafminer, Tuta absoluta, poses a severe global agricultural threat due to its rapid leaf-mining behavior and swift development of resistance to conventional chemical pesticides. While microbial chitinases are potent biopesticides, their field efficacy is limited by environmental degradation and the short exposure window before larvae penetrate leaf tissues. This study evaluates a stimuli-responsive, controlled-release nanobiopesticide system utilizing a novel chitinase from newly characterized Serratia marcescens GBS19. A 61.1 kDa chitinase (GBS19_ChiA) was heterologously expressed in Escherichia coli and purified to a specific activity of 215.01 U/mg. The enzyme was immobilized onto starch-coated silica nanoparticles designed for target-triggered release via host alpha-amylase. Genomic profiling and R-based kinetic modeling were integrated to evaluate the efficacy of purified and immobilized forms against T. absoluta. Immobilization enhanced thermal and pH stability, with the nanocarrier maintaining 85% activity over 10 weeks. In larval bioassays, immobilization increased mortality from 21.9% to 59.4% (5000 U/mL) by day 3, reaching 62.5% by day 6. Genomic analysis identified an expansive secretome and a Type VI Secretion System (T6SS), characterizing GBS19 as a multi-pronged pathogen. Kinetic modeling established that while immobilized enzymes are effective, the 2.5-hour exposure time on T. absoluta requires the synergistic action of chitinases (ChiA/B/C) to reach the lethal desiccation threshold before larvae establish protective mines. Starch-coated silica nanoparticles significantly improve chitinase stability and delivery. However, overcoming the rapid penetration of T. absoluta necessitates a whole-cell or multi-enzyme synergistic approach to outpace larval behavioural defences.

Hemp (Cannabis sativa L.) is an increasingly important crop with applications spanning fibre, seed oil and bioactive cannabinoid production, yet the development of reliable tissue culture systems for this species remains a significant challenge. The establishment of axenic seedling cultures is a prerequisite for hypocotyl-based regeneration and future genetic transformation pipelines, but hemp seeds harbour diverse endophytic microbial communities that frequently overwhelm standard surface sterilisation protocols. Here, we present a systematic comparative evaluation of seed sterilisation strategies across seven industrial hemp accessions, examining the effects of sterilisation chemistry, seed provenance and accession identity on both contamination outcome and the subsequent morphogenic competence of hypocotyl explants. Across all treatments and accessions, in-house glasshouse-harvested seeds achieved higher sterility rates than commercially sourced material regardless of protocol applied. This provenance effect, combined with considerable batch-to-batch variation within seed sources, indicates that contamination load is a primary determinant of successful hemp seed sterilisation. Among the sterilisation treatments evaluated, a baseline of 75% ethanol combined with sequential 1% hydrogen peroxide incubation performed consistently well for low-load seed batches, while supplementation with Plant Preservative Mixture (PPMTM) might be necessary to achieve acceptable rates of non-contaminated seedlings from high contamination load batches. Beyond their effect on contamination, sterilisation treatments influenced the morphogenic fate of hypocotyl explants independently of sterility outcomes. Notably, seedling treatment with the Prochloraz-based fungicide Octave promoted shoot and root co-regeneration in the absence of exogenous plant growth regulators in some cases. Hormone-free organogenesis from hypocotyl explants was achievable across multiple hemp accessions, demonstrating that this developmental capacity is broadly distributed within hemp, though its frequency and consistency varied with accession identity and protocol conditions. Together, these findings provide a practical framework for axenic hemp seed culture that can be used as starting point requiring local adaptation based on seed source, batch history and the intended downstream application.

Xylosandrus crassiusculus (Motschulsky), the granulate ambrosia beetle, was one of the first highly-destructive ambrosia beetles introduced into the southern U.S in the 1970s where it was found in South Carolina (Kovach 1986). The Redbay ambrosia beetle, Xyleborus glabratus Eichhoff, was first detected in the U.S. in South Georgia in 2002. This beetle and its associated fungi, the laurel wilt fungus Raffaelea laurelensis and others have caused substantial destruction to native redbay (Persea borbonia) in GA, SC, FL and elsewhere. This beetle-pathogen complex also poses a threat to commercial avocado production in the U.S., Central and South America as well as to valuable other Persea spp. and related plants (Laureacea) that are known hosts. As an addition here, 10 years of the spring appearances (Fig.1) of X. crassiusculus in North Florida is offered for future comparisons. A second unusual appearance is the finding and working with UV mulch and ethanol, as a surprising attraction of X. crassiusculus and other ambrosia beetles including X. glabratus. It was also found that the ambrosia beetles do not respond to yellow and green as expected by most. Also, adding burlap was found to be attractive (increases dead and dying appearing trees) as is silver metallic like UV mulch, while camouflage (camo) was found to work like yellow and green. These occurrences led to the invention and development of UV mulch with new traps to better monitor ambrosia beetles. New traps led to new uses for yellow, green and camo to monitor and decrease damage and losses from ambrosia beetles. The data are presented as evaluated and appear in the figures, discussion and a supplemental section. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=139 SRC="FIGDIR/small/733798v1_fig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@1006101org.highwire.dtl.DTLVardef@1e0a3d6org.highwire.dtl.DTLVardef@1244d1borg.highwire.dtl.DTLVardef@423cb7_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFigure 1:C_FLOATNO Relative timing of annual emergence of Xylosandrus crassiusculus in north Florida. Collected over 10 years using 5 Baker traps with a 10% ethanol/water solution. Data are from years as marked. Note: data from year 2003 was not collected. C_FIG

Objectives identified as critical for effective management of brown marmorated stink bugs, Halyomorpha halys Stal (BMSB), were addressed in the overwintering life stage. Research was conducted on a 675-acre farm in western Maryland, U.S.A. Developing and testing were done during September - October of each of the years 2013 - 2020. Traps and related materials were developed. Four invented traps plus the development and use of "weed beater" polyethylene plastic in combination with the other traps were used as attractions to BMSB during the overwintering testing periods. Overwintering BMSB showed very little interest other than to find a place to hide that was dry, dark, easy to get into and safe over the winter months (Nielson et al. 2016). Placement of traps show effect of cardinal directions due to heat and light were north = east > west = south of numbers of BMSB. These data were affected by the vegetation, type of buildings such as silos, cabins, houses, etc., around BMSB prior to the en masse flight. Silos were used as attractants from long range during the en masse flight. Five trap types were invented and tested for use against overwintering BMSB found various places such as buildings of any type, pathways in the woods and other habitats present. Trap #1 was made of plastic out of special plant pots, turned upside down with a plastic lid and entry holes top and bottom that allowed the BMSB to reach the hexcel inside and stay there. Trap #2 was made of white, rectangular coroplast and pressed into 0.5 x 0.5 x 7.32 m (5" x 5" x 24") box also holding hexcel. Traps #1 and #2 are useful for attachment to most anything with BMSB such as the eaves in houses, other buildings, vegetation, crevasses, etc. They can be placed as horizontal or vertical with other ways that enhance efficacy. Both #1 and #2 are cheap and easy to make and use. Trap #3 is made of a cardboard tube, as a fake or "faux" tree (dead and/or dying) in vegetation 20 cm (6-8") diameter and 1.22 m (3 or 4) long. The tubes are placed on tomato stakes, have hexcel and holes made as do the others and are placed vertically in the ground. The tubes are covered with small widths of white, black and or burlap around them. Lids of plastic are on top and the trap appears as a dead and/or dying tree. The fourth trap is a "mechanism" or resembling some kind of "Haven" if you will, made of "weed beater" plastic materials 1.98 m (66") wide in brown or black. The materials are placed on trees by wrapping them around 3-4 trees near 4.6 m (10-15 long). Traps 1 and 2 can then be placed on the outside of the plastic walls and the #3 fake trees can be added around the outside areas. Around 60,000 BMSB were collected and counted in these experiments by the author, and several different factors were raised and addressed to better understand the BMSB behavior during the overwintering stage. The results provide several new tools as well as understanding of approaches to address BMSB management better.

Metribuzin is a versatile herbicide effective against various annual grasses and broadleaf weeds found in wheat fields. However, it can cause foliar damage to wheat, impacting plant health and yield. A clearer understanding of the genetic architecture associated with metribuzin tolerance is necessary to guide marker-based breeding strategies. This study evaluated 351 historic Gulf Atlantic Wheat Nursery (GAWN) wheat breeding lines representative of southern US soft red winter wheat (SRWW) germplasm. Field trials were conducted at Winnsboro (WN) and Baton Rouge (BR), Louisiana, in 2016 and 2017. Metribuzin was applied at specific growth stages[DN1.1], and tolerance was assessed based on visual foliar damage. Genomic data from 6,252 filtered single nucleotide polymorphism (SNP) markers were used to estimate narrow-sense heritability, conduct genome-wide association (GWAS), and assess genomic prediction accuracy using genomic best linear unbiased prediction (GBLUP). Broad-sense heritability ranged from 0.54 to 0.69 within environments and reached 0.77 across environments, while narrow-sense heritability ranged from 0.35 to 0.47, indicating moderate additive genetic control. No SNP surpassed the significance threshold, but genomic prediction (GP) showed moderate to strong predictive ability (PA) across environments, with the highest accuracy (r = 0.62) observed between BR17 and WN17. These results indicate that metribuzin tolerance in SRWW is primarily controlled by multiple small-effect loci and that GS provides a more effective breeding strategy than marker-assisted selection for improving tolerance in southern wheat germplasm.

AbstractTomato production faces a persistent challenge from the tomato leaf miner, Phthorimaea absoluta, a pest that severely limits yields while effective resistance in cultivated varieties remains scarce. To address this gap, wild tomato relatives represent a promising reservoir of resistance traits. In this study, 24 tomato accessions, including both cultivated types and wild species, were evaluated under greenhouse (no-choice) and tunnel (choice) conditions. Resistance mechanisms were characterized through measures of antibiosis such as leaflet lesion type, proportion of attacked leaflets, and mine density. The results revealed substantial variation between and within species, allowing classification of accessions into resistant, intermediate, and susceptible groups through multivariate analysis. Notably, the wild accession Solanum habrochaites PI248707 exhibited strong resistance, in contrast to susceptible cultivated varieties such as Rose de Berne. Under choice conditions, PI248707 sustained limited damage and disrupted larval development, with early instar larvae present but few reaching advanced stages, indicating an inhibitory defense response. Untargeted metabolomic profiling further highlighted pronounced constitutive differences between wild and cultivated accessions, with S. pennellii and S. habrochaites displaying higher metabolic diversity. By integrating phenotypic and metabolic data, specific metabolite classes associated with resistance were identified. These findings underscore the potential of wild tomato germplasm in breeding programs, with PI248707 standing out as a strong candidate for resistance introgression.

Bacterial leaf blight (BB), caused by Xanthomonas oryzae pv. oryzae (Xoo), causes yield losses exceeding 50% in affected areas, including the Bagre rice plain in Burkina Faso. Genome-edited (GEd) rice lines have been successful in tackling BB. Modifications in the Xoo virulence protein target site upstream of three SWEET susceptibility genes in two elite rice varieties, IR64 and Ciherang-Sub1, have been demonstrated to confer broad-spectrum resistance to Asian and East African Xoo strains. Here, we evaluate the potential of the GEd lines as a solution for BB management in Burkina Faso. We challenged the GEd lines against five locally collected Burkinabe Xoo strains under controlled green-house conditions and assessed their agro-morphological performance under field conditions representative of local agroecological conditions. Greenhouse pathogen assays demonstrated that GEd IR64 and Ciherang-Sub1 lines were resistant to all tested local Xoo strains across three successive generations. We identified TalC as the primary disease-causing effector in the local Xoo populations. Irrigated field trials conducted over two seasons in the Kou Valley, Burkina Faso, revealed absence of agro-morphological penalties in GEd lines compared to their parental wild-type lines. Observed trait variation was attributable to environmental fluctuations rather than genomic modifications. Collectively, our findings demonstrate that genome editing of the rice lines does not impose growth penalties, and support the suitability of GEd IR64 and Ciherang-Sub1 for large-scale adoption in Burkina Faso, pending multi-location validation and introgression into locally adapted varieties.

Septoria nodorum blotch (SNB) is an economically important fungal disease of wheat caused by Parastagonospora nodorum. It is primarily controlled by the breeding of resistant wheat cultivars, but experience over the last 50 years shows that new pathogen populations soon evolve that are more virulent on the current popular cultivars. In this study, we assembled a panel of 360 P. nodorum isolates. The collection resolved into eight subpopulations. One core and seven transient populations were found possessing contrasting characters in term of spatial and temporal distribution, mating-type, effector haplotypes and patterns of intact and degraded copies of a Tc-1 mariner transposon, called Molly. Molly can proliferate and randomly insert throughout the fungal genome. Its multiplication in sexual population likely triggered RIP which partially explains the extensive genetic diversity and explains the ability to form new adapted lineages and the observed population structure of this important pathogen of wheat. When tested on wheat, the recently emerged groups exhibited greater pathogenicity on modern elite cultivars consistent with the low-amplitude boom-and-bust cycle observed previously. It is possible that active copies of Molly transpose and contribute to both the birth and death of the transient groups. This study identified and characterised a fungal specific transposable element (TE) which plays a vital role in shaping Australian P. nodorum population structure and creating extensive genetic diversity which potentially leads to better adaptation of the pathogen. The study suggests practical measures to improve the efficiency and longevity of resistance breeding for SNB.

Survival analysis is a workhorse assay in Drosophila research to evaluate somatic fitness. It is indispensable in the study of ageing and insightful in immunity, metabolism, radiobiology, toxicology, ecology, and others. While conceptually simple, lifespan measurement is labour-intensive because it requires the continuous manual maintenance of large experimental cohorts. Here, we describe Drosben, an approach that combines a 3D-printed device to transfer flies from several vials simultaneously, a paper system for quick data recording and accompanying software that automatically digitalises life tables for analysis. We show that using Drosben reduces the time investment to perform lifespan assays by ~85%, with improved speed regardless of experience handling Drosophila vials. Using Drosben, we address the effects on longevity of chronic feeding of indole-acetic acid (IAA), naphthalene-acetic acid (NAA) and trimethoprim (TMP) -- compounds used to control heterologous targeted protein degradation systems. We find that IAA and NAA have noticeable deleterious effects while TMP has a small protective effect specifically in females. We further show that strong static magnetic fields do not affect Drosophila lifespan. Our work suggests that Drosben can cheaply accelerate research where lifespan is used as a life history trait.

A parasitic mite of honey bee brood (Tropilaelaps mercedesae), is spreading through populations of Apis mellifera honey bees in new regions and poses a major threat to honey bee health. Despite its clear threat, the biology of this mite is poorly understood, with gaps on such fundamental issues as how fast its populations can grow. This leaves the beekeeping world underprepared to plan for its arrival and management. In this study, we documented the growth of T. mercedesae populations in untreated A. mellifera colonies in Thailand and South Korea, and did the same for another parasitic mite (Varroa destructor) when possible. We found that the population growth of T. mercedesae was variable but could reach high levels (daily r of 0.010, 0.036, and 0.057), while the population growth of V. destructor (r = 0.021) matched previous estimates. Our results indicate that T. mercedesae populations can grow rapidly but they do not always attain this potential. Based on our results, humidity should be studied as a potential driver of population growth. If future work can reveal key drivers of T. mercedesae population growth, this would help predict infestations and help design management strategies that exploit the pest's biological vulnerabilities.

Long-distance movement in insects has crucial impacts on agriculture, human health, and biodiversity. Although it was long assumed that only large, specialist insects had the navigation capacity to support long-distance dispersal, recent studies have demonstrated that smaller insects, such as the tiny fruit fly Drosophila melanogaster, can maintain extended, straight paths while flying or walking. This raises the question of whether other Drosophila species possess the navigation capacity to support extended dispersal. Resolving this question is particularly important for Drosophila suzukii(spotted-wing drosophila), a potent pest species that causes enormous damage worldwide to ripe fruit and berries. Spotted-wing drosophila has been thought to lack a capacity for long-distance dispersal, as prior studies have estimated maximal daily dispersal distances of less than 90 m. We developed a system to continuously track the flight trajectories of magnetically tethered D. suzukii relative to a discrete, overhead LED that mimicked the sun. We found that flies maintained remarkably straight flight headings that varied unpredictably across individuals. Male and female D. suzukii exhibited a similar navigation capacity; both sexes responded to rotation of a discrete sun stimulus with compensatory turns to maintain a stable relative heading. Our results suggest that D. suzukiihas an underappreciated capacity for rapid, radial dispersal, which could exceed 250 m in 15 min. This capacity may contribute to the pest species' invasiveness and its reliable, annual re-establishment in seasonally intolerable climates. Our findings highlight the importance of developing area-wide, regional strategies to manage the impacts of D. suzukii.

Alternaria mycotoxins represent an emerging concern due to their frequent occurrence in food and feed. However, available toxicological data remain limited. Under the current EU regulatory framework, and in line with the EFSA/ECHA/JRC guidance for the identification of endocrine disruptors (EDs), assessment of endocrine activity relies on standardized assays performed according to OECD Test Guidelines (TGs) for the estrogen-, androgen- and steroidogenesis- (EAS) modalities. Within the framework of the European Partnership for the Assessment of Risks from Chemicals (PARC), standardized in vitro methods of regulatory relevance were performed for six chemically characterized Alternaria toxins, aiming to address current regulatory gaps on EAS-mediated activity. Alternariol (AOH), alternariol monomethyl ether (AME), tenuazonic acid (TeA), altertoxin-I (ATX-I), tentoxin (TEN) and altenuene (ALT) were assessed over a broad concentration range, from 0.001 up to 60 M, depending on cytotoxicity and solubility profile of each compound. Our findings indicate estrogenic activity for AOH (PC50: 3.9 - 4.6 {micro}M) and AME (PC50: 5.2 - 8.5 {micro}M) in the estrogen receptor transactivation assay (OECD TG 455), as well as an anti-estrogenic activity for ATX-I (IC30: 0.27 - 0.37 {micro}M). Minimal positive responses were observed at high concentrations for AOH (from the dose of 3 {micro}M) and for AME (from the dose of 10 {micro}M) in the agonistic part of the androgen receptor transactivation assay (OECD TG 458), which may also reflect glucocorticoid receptor activation. No effects on estradiol or testosterone production were observed for any of the tested Alternaria compounds in the steroidogenesis assay (OECD TG 456).

Light leaf spot (LLS), caused by subcuticular hemibiotrophic ascomycete fungus Pyrenopeziza brassicae, is a major constraint on oilseed rape (Brassica napus) production, yet the genetic and biochemical mechanisms of quantitative disease resistance (QDR) remain poorly defined. Here, disease phenotyping, pathogen quantification, microscopy, gene expression profiling and glucosinolate (GSL) analysis were integrated to dissect resistance mechanisms in B. napus. Disease assays of 19 diverse lines revealed clear contrasts between susceptible and resistant genotypes, with the commercial cultivar Ambassador showing a phenotype inconsistent with the UK Recommended List rating. Microscopy demonstrated that resistance within doubled haploid line Cubs Root does not inhibit spore germination or penetration but restricts hyphal branching and subcuticular colonisation from 4 to 8 days post-inoculation. Expression profiling of seven candidate gene expression markers (GEMs) and pathogenesis-related PR1 showed that cinnamate-4-hydroxylase, phospholipase C4, {beta}-adaptin, universal stress protein and the 40S ribosomal subunit protein S24 were strongly pathogen-induced in resistant lines, whereas a BAHD acyltransferase, a putative susceptibility factor, was induced only in susceptible cultivars. GSL profiling identified negative correlations between disease severity and total GSLs, particularly aliphatic and aromatic GSLs, with 2{square}phenylethyl and 7-methylsulfinyl heptyl GSLs showing the strongest associations with resistance. Together, these results highlight coordinated transcriptional and metabolic responses that limit pathogen proliferation and provide targets for breeding durable LLS resistance in B. napus.

Organisms have spent their life histories exposed to background levels of natural ionizing radiation. To document the role that radiation plays, the deprivation of these natural levels has been studied by incubating organisms in the shielded space of underground laboratories. We report here on two studies (Study I and Study II) using Aedes aegypti for the first time as a model organism incubated 655 meters underground at the Waste Isolation Pilot Plant (WIPP) outside of Carlsbad, New Mexico, U.S.A. Male mosquitos were incubated at the surface exposed to natural background radiation, and were compared to two underground treatments in which incubators were supplemented with radiation sources used to mimic background and these groups were compared to the underground, radiation-deprived treatment. In Study I, the mosquitos incubated underground in the absence of natural radiation had higher levels of mortality compared to those incubated at the surface and PCA plots of the two transcriptomes were clearly differentiated. Study II was conducted the following year and the experiment was narrowed to include only the surface control and underground, radiation-deprived treatment which allowed for four biological replicates. Again, there was a higher level of mortality in the mosquitos grown underground compared mosquitos grown at the surface. Transcriptomes were not as clearly differentiated by PCA analysis and fecundity data were similar between the two groups. Functional analysis of transcriptomic DEGs from two independent studies suggested there are stress responses in radiation deprived mosquitoes. The absence of a secondary stressor in Study II is discussed as an explanation for the transcriptome differences in the two experiments.

BackgroundThe commercialization of Nigerias single-line pod borer-resistant (PBR) cowpea (IT97KT), the first transgenic cowpea variety in the world expressing Cry1Ab gene, has raised questions about potential unintended molecular changes and their ecological implications. This study employed integrated proteomic and metabolomic profiling to compare the transgenic line with its non-transgenic isoline (IT97KN) and assess molecular indicators associated with ecosystem resilience. MethodsProteomic analyses were conducted using LC-MS/MS following filter-assisted sample preparation, while metabolomic profiling employed GC-MS and UHPLC-MS/MS platforms. Differential protein and metabolite abundance were assessed using label-free quantification, volcano plot analysis, principal component analysis (PCA), hierarchical clustering, and Gene Ontology (GO) enrichment analyses. ResultsProteomic profiling revealed substantial overlap between IT97KT and IT97KN, with only a limited subset of proteins exhibiting significant differential abundance. Upregulated proteins in IT97KT were primarily associated with seed storage, redox regulation, oxidative stress mitigation, and defense-related functions, including Late Embryogenesis Abundant Protein 1 (LEA1), vicilins, thioredoxin, and iron superoxide dismutase. Among 37 proteins linked to ecological adaptation, only LEA1, CPRD22, and Bg7S showed significant differences. Similarly, only carbonic anhydrase II displayed differential abundance among proteins associated with potential ecological risk. PCA and clustering analyses demonstrated high proteomic similarity between genotypes. Metabolomic analyses identified sixteen major metabolites, predominantly fatty acids, with no statistically significant differences in abundance or composition between transgenic and non-transgenic lines ConclusionsThe transgenic PBR cowpea exhibited minimal unintended proteomic and metabolomic alterations relative to its non-transgenic isoline. These findings indicate that Cry1Ab insertion did not substantially disrupt molecular pathways associated with ecological adaptation, environmental risk, or metabolic homeostasis, providing molecular evidence supporting the environmental and biosafety equivalence of PBR cowpea.