Julius Kühn-Institut

Gut microbial diversity influences the health and vitality of the host, yet it is itself affected by internal and external factors, including land-use. The impact of land-use practices on wild rodents' gut microbiomes remains understudied, despite their abundance and potential as reservoirs for zoonotic pathogens. We examined the bacterial and fungal gut microbiomes of bank voles (Myodes glareolus) and common voles (Microtus arvalis) across grassland and forest habitats with varying land-use intensities and types. We collected rodents seasonally and used 16S rRNA and ITS amplicon sequencing for microbe identification. We found significant differences in alpha and beta diversities between the species, with M. arvalis exhibiting higher diversity. Seasonality emerged as a prominent factor influencing microbial diversity, with significant variations between sampling months. While land-use affects the gut microbiome, its impact is subordinate to seasonal variations. Differential abundance analysis underscores the dynamic nature of microbial composition, with seasonal changes playing a predominant role. Overall, our findings highlight the significant influence of seasonality on gut microbiome diversity and composition in wild rodents, reflecting dietary shifts associated with seasonal changes. Understanding the interplay between environmental factors and microbial communities in wild rodents enahnces our knowledge of ecosystem health and resilience, warranting further investigation.

In the ongoing pursuit of sustainable farming techniques, the constant fight against aphids remains an essential frontier. Aphids are well-known agricultural pests and they continue to jeopardize global crop production, necessitating an immediate demand for sustainable pest control methods. Conventional chemical insecticides not only harm the quality of crops but also cause environmental damage. This comprehensive review starts with a meta-analysis using PRISMA approach, to present innovative, environmentally friendly alternative technologies, the latest developments and advances in aphid control that can reduce pressure on the environment and contribute to a more sustainable aphid control. Good alternative technologies include bioengineered nanoparticles, RNAi and CRISPR/Cas9. In addition, there has been progress in the existing use of natural enemies with parasitoids and predators with increased efficacy, as well as the area of microbial control of aphids with entomopathogenic fungi and bacteria. Because monitoring is very important and a cornerstone of integrated pest management, the latest advances in artificial intelligence and deep learning in aphid control are helping to reduce pressure on the environment and contribute to a reduction in the use of chemicals, supporting the preservation of biodiversity and sustainability, which fits with the policy in many continents. Altogether, this paper aims to provide a valuable guidance for researchers, practitioners and policymakers who are involved in the complex dynamics of aphid control in agriculture.

Frontal alpha asymmetry has been proposed as a ubiquitous marker of state and trait approach motivation, but recent meta-analyses found weak or nonexistent links with personality traits. It has been suggested that frontal asymmetry may show stronger individual differences in situations that elicit approach motivation (state–trait interaction). To investigate this with sufficient statistical power, we utilized data from the CoScience project (N = 740). Frontal asymmetry was measured during a resting period, a picture viewing task, and a guessing task, which were expected to trigger different levels of approach motivation. Results showed that frontal asymmetry was not reliably affected by task manipulations and did not relate to self-reported traits. Furthermore, Bayesian statistics and a cooperative forking path analysis were used to supplement the preregistered analyses. To conclude, this comprehensive analysis could not support the validity of frontal asymmetry as a marker of approach motivation, neither as a reliable state nor as a trait marker.

In August 2024, adult individuals of Scaphoideus titanus were detected for the first time in Germany on yellow sticky traps in two different vineyards ( Vitis vinifera ) in Baden‐Württemberg. This leafhopper is the main vector of Grapevine flavescence dorée phytoplasma (FD). According to initial analyses, however, the flavescence dorée‐causing phytoplasma could not be detected in the trapped leafhoppers. An area of 80 hectares of non‐contiguous vineyards is declared as infested.

Pangenomes are collections of annotated genome sequences of multiple individuals of a species¹. The structural variants uncovered by these datasets are a major asset to genetic analysis in crop plants². Here we report a pangenome of barley comprising long-read sequence assemblies of 76 wild and domesticated genomes and short-read sequence data of 1,315 genotypes. An expanded catalogue of sequence variation in the crop includes structurally complex loci that are rich in gene copy number variation. To demonstrate the utility of the pangenome, we focus on four loci involved in disease resistance, plant architecture, nutrient release and trichome development. Novel allelic variation at a powdery mildew resistance locus and population-specific copy number gains in a regulator of vegetative branching were found. Expansion of a family of starch-cleaving enzymes in elite malting barleys was linked to shifts in enzymatic activity in micro-malting trials. Deletion of an enhancer motif is likely to change the developmental trajectory of the hairy appendages on barley grains. Our findings indicate that allelic diversity at structurally complex loci may have helped crop plants to adapt to new selective regimes in agricultural ecosystems.

Interaction between plant parasitic nematodes and their host plants is a dynamic process. While plants employ different defensive strategies to limit or avoid nematode infection, plant parasitic nematodes utilise various strategies to suppress plant defence. However, in the meantime, beneficial microorganisms can support plants in enhancing their defence mechanisms against pathogens. Nematophagous fungi can reduce infection of plant parasitic nematodes via direct parasitism and triggering plant defence system, having positive impacts on plant growth. We investigated the effect of the two nematode egg parasitising fungi Niesslia gamsii and Polydomus karssenii on nematode suppression in soil using greenhouse experiments by evaluating the potential of these fungi on direct parasitism against nematodes and by analysing the expression of plant defence related genes using quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). Niesslia gamsii and P. karssenii were originally isolated from naturally infested eggs of the cereal cyst nematode Heterodera filipjevi , and their nematode pathogenicity was proven through Koch’s postulates. Here we report on their parasitism towards the root-knot nematode Meloidogyne hapla on tomato, where both fungi could significantly reduce the number of nematode eggs or second stage juveniles (J2) in tomato roots as well as the nematode reproduction rate. Both fungi also impeded nematode root invasion by limiting nematode penetration into tomato roots 3 and 7 days after being inoculated with the M. hapla J2. The results obtained in this study showed a substantial effect of both fungi on inducing defence responses in tomato plants towards M. hapla . Pre-treatment with N. gamsii and P. karssenii led to the expression of different marker genes associated with pathogen response pathways, including salicylic and jasmonic acid/ethylene regulated defensive. These findings suggest that N. gamsii and P. karssenii could prime the plant host for enhanced defence upon nematode attack.

The Arctic is seasonally exposed to long periods of low temperatures and complete darkness. Consequently, perennial primary producers have to apply strategies to maximize energy efficiency. Global warming is occurring in the Arctic faster than the rest of the globe. The highest amplitude of temperature rise occurs during Polar Night. To determine the stress resistance of the ecosystem-engineering kelp Laminaria digitata against Arctic winter warming, non-meristematic discs of adult sporophytes from Porsangerfjorden (Finnmark, Norway) were kept in total darkness at 0°C and 5°C over a period of three months. Physiological variables, namely maximum quantum yield of photosynthesis (Fv/Fm) and dry weight, as well as underlying biochemical variables including pigments, storage carbohydrates, total carbon and total nitrogen were monitored throughout the experiment. Although all samples remained in generally good condition with Fv/Fm values above 0.6, L. digitata performed better at 0°C than at 5°C. Depletion of metabolic products resulted in a constant decrease of dry weight over time. A strong decrease in mannitol and laminarin was observed, with greater reductions at 5°C than at 0°C. However, the total carbon content did not change, indicating that the sporophytes were not suffering from “starvation stress” during the long period of darkness. A decline was also observed in the accessory pigments and the pool of xanthophyll cycle pigments, particularly at 5°C. Our results indicate that L. digitata has a more active metabolism, but a lower physiological and biochemical performance at higher temperatures in the Arctic winter. Obviously, L. digitata is well adapted to Arctic Polar Night conditions, regardless of having its distributional center at lower latitudes. Despite a reduced vitality at higher temperatures, a serious decline in Arctic populations of L. digitata due to winter warming is not expected for the near future.

BACKGROUND The hemibiotrophic fungus Zymoseptoria tritici causing Septoria tritici blotch (STB), is a devastating foliar pathogen of wheat worldwide. A common group of fungicides used to control STB are the demethylation inhibitors (DMIs). DMI fungicides restrict fungal growth by inhibiting the sterol 14‐α‐demethylase, a protein encoded by CYP51 gene and essential for maintaining fungal cell permeability. However, the adaptation of Z. tritici populations in response to intensive and prolonged DMI usage has resulted in a gradual shift towards reduced sensitivity to this group of fungicides. In this study, 311 isolates were collected pre‐treatment from nine wheat‐growing regions in Europe in 2019. These isolates were analysed by high‐throughput amplicon‐based sequencing of nine housekeeping genes and the CYP51 gene. RESULTS Analyses based on housekeeping genes and the CYP51 gene revealed a lack of population structure in Z. tritici samples irrespective of geographical origin. Minimum spanning network (MSN) analysis showed clustering of multilocus genotypes (MLGs) based on CYP51 haplotypes, indicating an effect of selection due to DMI fungicide use. The majority of the haplotypes identified in this study have been reported previously. The diversity and frequencies of mutations varied across regions. CONCLUSION Using a high‐throughput amplicon‐sequencing approach, we found several mutations in the CYP51 gene combined in different haplotypes that are likely to cause fungicide resistance. These mutations occurred irrespective of genetic background or geographical origin. Overall, these results contribute to the development of effective and sustainable risk monitoring for DMI fungicide resistance. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Machine learning methods were shown to improve the prediction accuracies of genomic prediction of resistance scores compared to methods like RR‐BLUP, which were originally designed for metric rather than ordinal response values. We conducted a cross‐validation study with 361 wheat genotypes evaluated for five fungal diseases. Our objective was to compare the prediction accuracy and the ability to identify the most resistant genotypes of 19 genomic prediction approaches. Each approach consisted of a different combination of prediction method (RR‐BLUP, an alternative method with heterogeneous marker variances, Bayesian generalized linear regression with an ordinal response, support vector machine, gradient boosting machine and random forest), predictor (single SNP markers, LD‐based haplotype blocks, 250 variables generated with an autoencoder and SNPs identified with incremental feature selection) and response value (untransformed and logit‐transformed resistance scores). In our dataset, RR‐BLUP was consistently among the methods with the largest prediction accuracies and the best abilities to identify resistant genotypes in four of five investigated traits. However, in P. triticina , using gradient boosting machine and random forest instead of RR‐BLUP increased the prediction accuracy from 0.64 to 0.71, indicating that machine learning methods may have an advantage over linear models in genomic prediction. We also found that even though there was a positive correlation between the prediction accuracy and Cohen's , a measure to judge how well the most resistant genotypes can be identified, the correlation is not perfect and a large value for the prediction accuracy does not necessarily translate into an equally large value.

Convective storms with strong downdrafts create windthrows: snapped and uprooted trees that locally alter the structure, composition, and carbon balance of forests. Comparing Landsat imagery from subsequent years, we documented temporal and spatial variation in the occurrence of large (≥30 ha) windthrows across the Amazon basin from 1985 to 2020. Over 33 individual years, we detected 3179 large windthrows. Windthrow density was greatest in the central and western Amazon regions, with ∼33% of all events occurring in ∼3% of the monitored area. Return intervals for large windthrows in the same location of these “hotspot” regions are centuries to millennia, while over the rest of the Amazon they are >10,000 years. Our data demonstrate a nearly 4‐fold increase in windthrow number and affected area between 1985 (78 windthrows and 6,900 ha) and 2020 (264 events and 32,170 ha), with more events of >500 ha size since 1990. Such extremely large events (>500 ha up to 2,543 ha) are responsible for interannual variation in the overall median (84 ± 5.2 ha; ±95% CI) and mean (147 ± 13 ha) windthrow area, but we did not find significant temporal trends in the size distribution of windthrows with time. Our results document increased damage from convective storms over the past 40 years in the Amazon, filling a gap in temporal records for tropical regions. Our publicly accessible large windthrow database provides a valuable tool for exploring dynamic conditions leading to damaging storms and their ecological impact on Amazon forests.

Background Precision phenotyping of short-term transpiration response to environmental conditions and transpiration patterns throughout wheat development enables a better understanding of specific trait compositions that lead to improved transpiration efficiency. Transpiration and related traits were evaluated in a set of 79 winter wheat lines using the custom-built “DroughtSpotter XXL” facility. The 120 l plant growth containers implemented in this phenotyping platform enable gravimetric quantification of water use in real-time under semi-controlled, yet field-like conditions across the entire crop life cycle. Results The resulting high-resolution data enabled identification of significant developmental stage-specific variation for genotype rankings in transpiration efficiency. In addition, for all examined genotypes we identified the genotype-specific breakpoint in transpiration in response to increasing vapour pressure deficit, with breakpoints ranging between 2.75 and 4.1 kPa. Conclusion Continuous monitoring of transpiration efficiency and diurnal transpiration patterns enables identification of hidden, heritable genotypic variation for transpiration traits relevant for wheat under drought stress. Since the unique experimental setup mimics field-like growth conditions, the results of this study have good transferability to field conditions.

Residues of plant protection products (PPPs) are frequently detected in bee matrices1,2,3,4,5,6 due to foraging bees collecting contaminated nectar and pollen, which they bring back to their hive. The collected material is further used by nurse bees to produce glandular secretions for feeding their larvae.7 Potential exposure to PPPs occurs through direct oral ingestion, contact during foraging, or interaction with contaminated hive material.8,9 Contaminants can pose health risks to adult worker bees,10,11 queens,12,13 drones (males),14 or larvae,15,16 potentially impacting colony health and productivity. However, residue concentrations can vary significantly between analyzed matrices, and potential accumulation or dilution steps have not been widely investigated. Although research has provided valuable insights into contamination risks, there remain gaps in our understanding of the entire pathway from field, via foragers, stored products, nurse bees, and finally to food jelly, i.e., royal, worker, and drone jelly, and the larvae, including all possible processing steps.17 We collected samples of bee-relevant matrices following the in-field spray application of the product Pictor Active, containing the fungicides boscalid and pyraclostrobin. The samples were analyzed for residues along this entire pathway. Fungicide residues were reduced by a factor of 8–80 from stored product to nurse bees’ heads, suggesting a filtering function of nurse bees. Furthermore, detected residues in larval food jelly resulted from added pollen and not from nurse bee secretions. Calculated risk quotients were at least twice as low as the threshold values, suggesting a low risk to honey bee colonies from these fungicides at the tested application rate.

Loss of stored plant products due to insect infestation is a problem that is likely to increase with global warming. Improved storage under hermetic conditions in oxygen deficiency can prevent or control infestation and preserve product quality. Oxygen levels in hermetic storage decrease due to different factors, one of which is the oxygen consumption of the insects present. Experiments were carried out using varying numbers (25, 50, or 200) of all developmental stages of the grain weevil Sitophilus granarius L. (eggs, larvae, pupae, and adult beetles) caged and placed in sealed 30-L containers containing 22 kg of wheat for at least 21 weeks. Oxygen levels were measured at regular intervals. The oxygen consumption depended on the number of insects and went below the critical threshold of 3% for S. granarius survival in most of the trials. Some surviving beetles were observed at the end of the hermetic experiments and 12 weeks afterwards during control for progeny, when oxygen levels did not fall below the critical threshold or the low level could not be maintained for a sufficient time. Monitoring oxygen levels in hermetic storage is therefore essential to ensure safe storage over long periods.

Diplocarpon coronariae is a fungal pathogen that is prevalent in low-input apple production. Over the past 15 years, it has become increasingly distributed in Europe. However, comprehensive insights into its biology and pathogenicity remain limited. One particular aspect is the rarity of the sexual morph of this pathogen, a phenomenon hitherto unobserved in Europe. Diplocarpon coronariae reproduces through a heterothallic mating system requiring at least two different mating types for sexual reproduction. Genes determining the mating types are located on the mating-type locus. In this study, D. coronariae strain DC1_JKI from Dresden, Germany, was sequenced and used to unravel the structure of the mating type locus. Using short-read and long-read sequencing methods, the first gapless and near-complete telomere-to-telomere genome assembly of D. coronariae was achieved. The assembled genome spans 51.2 Mbp and comprises 21 chromosome-scale contigs of high completeness. The generated genome sequence was used to in silico elucidate the structure of the mating-type locus, identified as MAT1-2. Furthermore, an examination of MAT1-1 and MAT1-2 frequency across a diverse set of samples sourced from Europe and Asia revealed the exclusive presence of MAT1-2 in European samples, whereas both MAT loci were present in Asian counterparts. Our findings suggest an explanation for the absence of the sexual morph, potentially linked to the absence of the second mating idiomorph of D. coronariae in European apple orchards.

The objectives of the study were to examine the effect of an antibiotic solution applied in the Streptomyces griseus protease method (SGPM) and the effect of carbohydrases in SGPM on the effective crude protein (CP) degradation (ED) with reference to in sacco ED. For this purpose, the ruminal CP degradation of rapeseed meal, dried distillers’ grains with solubles, wheat grain, corn grain, corn silage, grass silage and partial crop field pea silage was determined in sacco using three rumen-fistulated dairy cows and in vitro using SGPM. The impact of the antibiotic solution on CP degradation by S. griseus protease was investigated by supplementing SGPM with Penicillin–Streptomycin solution to reduce microbial mass proliferation during incubation. The carbohydrase α-amylase or Viscozym® L (cell wall-degrading enzyme mixture) was added to the SGPM at four different doses simultaneously as a co-incubation to improve feed protein accessibility. For most feedstuffs, ED was lower when the antibiotic solution was used in SGPM (p < 0.05). The use of an antibiotic solution in the SGPM is recommended to standardize the SGPM. The in sacco ED values were significantly underestimated by the SGPM and by the SGPM with co-incubated carbohydrase (p < 0.05). Co-incubation of S. griseus protease and carbohydrase was not successful in reducing the differences to the in sacco CP degradation.

In agricultural landscapes, the removal of semi‐natural habitats (SNH) and the intensive use of pesticides contribute to declines of biodiversity, including crop pollinators such as bees (Hymenoptera: Apoidea). However, effects of pesticide use and landscape characteristics on bees have rarely been studied together. In this study, we investigated how SNH in the surrounding landscape, organic and conventional management, and the reduction of fungicides affect wild bee diversity in 32 vineyards in southwest Germany. We used yellow pan traps to sample bees in a crossed design of management (organic vs. conventional) and fungicide use (reduced in fungus‐resistant grape varieties vs. regular) along a gradient with increasing proportions of SNH in the surrounding landscape. Higher proportions of SNH influenced species composition of bees and increased the abundance and richness of above‐ground‐nesting species. Organic vineyards had a 49% higher abundance of bees compared to conventional vineyards. The reduction of fungicides did not affect bee diversity nor abundance. The absence of a response to fungicide intensity suggests that the benefit of organically managed vineyards to wild bees was through differences in their vegetation management, which is in line with the positive response of bees to SNH in the surrounding landscape. Synthesis and applications: Our study underlines that the local provision of diverse vegetation in vineyards and the landscape‐scale provision of suitable SNH are key factors for wild bee conservation in viticulture.

The spread of potato cyst nematodes (Globodera pallida and Globodera rostochiensis) via residual soils endangers the cultivation of potatoes. The aim of the study was to investigate the effectiveness of thermal treatments against potato cyst nematodes (PCN) as part of reliable routine phytosanitary measures in processing plants accompanied with the highest possible throughput of tare soil. The viability and reproduction rates of potato cyst nematodes embedded in gauze sachets in a residual soil matrix were tested after treatment with dry heat, hot steam, or microwaves. An 80 °C heating by microwaves in a magnetron tunnel, which was reached after 2–7 min, was found to inactivate the potato cyst nematodes after 15 s of exposure. The data indicate that conductive heating in the Sterilo effectively kills cysts in soils when heated to 68 °C and allowed to cool down for 16 h. Inactivation of cysts was also found, when hot steam treatment (adjusted to 80 °C) was applied for 5–6 h, followed by a cooling phase for at least 18 h. We conclude that PCN’s viability and the ability to reproduce on susceptible potato plants is eliminated after thermal treatment at 80 °C with microwaves as the most effective measure with the lowest energy effort.

The spread of toxigenic Aspergillus into maize by insects and the subsequent aflatoxin contamination poses a risk to humans and animals and has been investigated in North and South America. To evaluate this effect in an African context, Greenhouse studies were conducted in 2022 to determine the role of sap beetles, Carpophilus dimidiatus Fabricius, 1792 (Coleoptera: Nitidulidae) and maize weevils, Sitophilus zeamais Motschulsky, 1855 (Coleoptera: Curculionidae) on infection of maize kernels by Aspergillus flavus Link and the resultant aflatoxin accumulation. To test the beetles’ efficacy, treatments were applied on partially opened primary ears at 3 different stages of kernel development (BBCH 75, 83, and 87). The treatments were: (i) distilled water, (ii) water with A. flavus spores, (iii) maize grits, (iv) maize grits with A. flavus spores, (v) C. dimidiatus, (vi) C. dimidiatus with A. flavus spores, (vii) S. zeamais, and (viii) S. zeamais with A. flavus spores. Data on kernel infection, maize rotting, yield, and aflatoxin content in kernels were collected. The highest kernel spoilage and yield loss were recorded for the co-inoculation of S. zeamais and A. flavus spores, followed by S. zeamais without A. flavus spores, and then C. dimidiatus with the fungal spores. Inoculation of maize at the BBCH 83 growth stage resulted in the highest kernel damage and aflatoxin contamination. S. zeamais and, to a lesser extent, C. dimidiatus effectively spread the A. flavus inoculum into non-wounded ears, resulting in fungal and aflatoxin contamination. The yield loss from S. zeamais-Aspergillus co-inoculation occurred due to the grain rotting and actual feeding of the maize weevils. Thus, insect management is important in reducing pre-harvest contamination of maize with mycotoxigenic fungi and their resultant toxins.