Streptomyces spp. are the main producers of antimicrobial and other bioactive compounds, which determined the interest of researchers in representatives of this genus. A hypothesis was proposed suggesting that the strain possessed a broad metabolite spectrum and a potential ability to synthesize diverse antibiotics, including those with larvicidal, anthelmintic, and antimicrobial properties. It exhibited antagonistic activity against phytopathogenic fungi and was considered promising for biotechnological applications in agriculture. The aim of this study was to perform whole-genome sequencing in order to determine the evolutionary relationships and biosynthetic potential of Streptomyces distallicus IMV Ac-5025, with particular emphasis on its capacity to produce antimicrobial compounds. Whole-genome sequencing was performed using an Illumina NovaSeq 2 × 150 bp and assembled with the SPAdes v4.0.0 method and was annotated. The search for similar genomes and genomic phylogeny was conducted at the Bacterial and Viral Bioinformatics Resource Centre. Biochemical tests using minimal nutrient media were performed to determine phenotypic characteristics of the strain. Crude extracts were analyzed for the presence of antibiotics using Q Exactive liquid chromatography-tandem mass spectrometry and high-performance liquid chromatography. The antibiotics susceptibility was assessed using a modified disk diffusion method, antifungal activity was determined using a dual-block confrontation assay. The genome assembly yielded 8 contigs, with a total length of 7,564,690 bp. Analysis of the biosynthetic gene clusters revealed a broad biosynthetic potential of the strain, notably including clusters associated with antibiotic production. The strain was found to synthesize aureothin and distamycin, which, in addition to its antifungal activity, broaden the spectrum of its bioactivity. Cultivation conditions affected aureothin production, with the highest yield (52.321 ± 0.957 ug/uL) obtained by ethanolic extraction from biomass when the producer grown in GYM nutrient medium. The results highlight the biotechnological potential of secondary metabolites from S. distallicus IMV Ac-5025, which combine strong antifungal activity with promising nematicidal properties, thereby supporting their relevance for integrated plant protection strategies.

Consortia of microbial isolates, also known as synthetic communities (SynComs), are increasingly used to study and harness microbe-microbe and microbe-host interactions. Since “synthetic” potentially evokes negative connotations, we propose adopting the term “Defined Microbial Community” for practical applications.

Abstract Microbial pesticides are increasingly important for sustainable crop protection, yet hazard analysis and risk assessment remain challenging and require specific characterization of properties relevant to both safety and biological activity. Whole-genome sequencing (WGS) can support the identification of microorganisms at high resolution and characterize potential hazards associated with infectivity, pathogenicity, antimicrobial resistance, and toxic metabolite production. However, the routine use of WGS in this context requires accessible, reproducible, and interpretable workflows. Here, we present a publicly available web-based workflow for WGS-supported hazard analysis of microbial biocontrol agents. The workflow accepts assembled genomes as well as short-read, long-read and hybrid sequencing data, and performs genome quality assessment, taxonomic assignment, genome annotation, AMR detection, mobile-element screening, pathogenicity prediction and secondary-metabolite analysis, and compiles the results into an HTML report. For bacterial agents, we implement a transparent rule-based risk-classification module integrating taxonomic identity, PathogenFinder2 predictions, CARD/RGI resistance evidence, WHO priority taxa, and medically important antimicrobial categories. Secondary-metabolite assessment combines antiSMASH with local BLAST searches and EFSA-aligned identity/coverage thresholds to support product-level interpretation of biosynthetic gene clusters. Comparison with the currently used MOpS workflow developed by EFSA demonstrates the added benefits of the proposed workflow for a guided hazard analysis of microbial pesticides. The workflow is intended as a community-accessible pre-assessment tool that complements regulatory platforms by improving transparency, reproducibility, and early identification of potential hazards in microbial biocontrol candidates, envisioned to make WGS an integral part of the risk assessment of microbial pesticides. Key points The RATION-GUI provides a public, reproducible workflow for whole-genome sequencing– supported hazard characterization of bacterial and fungal microbial pesticides. The workflow integrates genome quality, taxonomy, annotation, antimicrobial resistance, pathogenicity-related evidence, mobile elements, and secondary-metabolite potential. Domain-specific outputs are translated into structured hazard indicators, evidence summaries, and recommended follow-up actions without replacing expert regulatory judgment. Case studies demonstrate how the workflow improves transparency, traceability, and interpretation of genomic evidence for microbial pesticide risk assessment.

Bacillus altitudinis GG-22, isolated from the phyllosphere of agricultural crops, has been identified as a promising biocontrol agent and plant growth-promoting bacterium with substantial potential in sustainable agriculture. In this study, whole-genome sequencing using Illumina technology, combined with ANI analysis, confirmed the strain's classification as B. altitudinis. The genome revealed a rich set of genes involved in biocontrol mechanisms, including the capacity of synthesis of siderophores (schizokinen and bacillibactin-like compounds), the lipopeptide pumilacidin, the bacteriocin pumilarin, alkylpyrones and Bacillus volatiles. In vitro antagonism assays demonstrated significant inhibitory effects against phytopathogenic fungi and oomycetes, such as Verticillium dahliae and Pythium sp., and B. altitudinis GG-22 also showed limited efficacy against bacterial phytopathogens, including Xylella fastidiosa. Transcriptomic profiling of olive trees treated with GG-22 indicated early activation of auxin transport and systemic acquired resistance (SAR) pathways, alongside substantial downregulation of cell wall remodelling genes. These findings suggest that B. altitudinis GG-22 primes plant defence responses and modulates hormonal pathways critical for growth and stress resilience. Future research should prioritize optimizing application strategies and exploring synergies with other microbial agents to fully harness the biocontrol and growth-promoting potential of B. altitudinis GG-22. This strain holds promise for sustainable agricultural practices, particularly in controlling fungal diseases and improving plant performance under stress conditions.

Vineyard green cover management, within the vine row, in interrows and also in the surrounding areas significantly affects vigor, yield performance and health of vines. The current study compares relatively new devices on the market for under-vine care based on the use of high voltage electricity (Zasso) and high-pressure water jets (Grasskiller) with mechanical management methods and a glyphosate-free chemical treatment. In terms of overall coverage, the mechanical devices inter-vine blade (Clemens, Wittlich, Germany) and Tournesol (Pellenc, Frankreich) gave the best results, followed by electrical application, in terms of vegetation height, all treatments were comparably effective. The study also recorded the effect of the measures against field bindweed (Convolvulus arvensis), which is a difficult-to-control vineyard weed, but also a crucial source of Stolbur Phytoplasma 'Candidatus Phytoplasma solani'. All under-vine treatments favoured field bindweed density, compared to the untreated control, with weed control using a high-pressure water jet performing worst. Overall, the experiments revealed no decisive advantages of electric weeding or high-pressure jets compared to conventional mechanical methods. The present study also included trials to reduce field bindweed density in vineyard interrows by means of seeded cover crop and cereal straw mulch, and around vineyards and along roadsides by largely reducing tillage (leaving the green cover long). In summary, the trials showed that competition and shading by other plant species was the most effective way of reducing field bindweed density. In order to keep the stolbur infection pressure on the vines as low as possible, it is therefore advisable to manage the green cover so that the field bindweed is shaded as much as possible. At the same time, however, competition between the vine and the greening, e.g., during dry periods, must be kept in mind. Die Begr & uuml;nungspflege in der Rebzeile, in der Fahrgasse und auch auf Fl & auml;chen rund um Weing & auml;rten spielt eine wichtige Rolle f & uuml;r die W & uuml;chsigkeit, die Ertragsleistung und die Gesundheit von Reben. In der hier dargestellten Studie wurden relativ neu am Markt befindliche Ger & auml;te zur Unterstockpflege, basierend auf Hochspannungs-Stromanwendung (Zasso) und Hochdruckwasserstrahl (Grasskiller) mit mechanischen Methoden und einer glyphosatfreien chemischen Unterstockbehandlung verglichen. Betreffend den Gesamtdeckungsgrad erzielten die mechanischen Ger & auml;te Flachschar (Clemens, Wittlich, Deutschland) und Tournesol (Pellenc, Frankreich) die besten Ergebnisse, gefolgt von Stromanwendung, im Hinblick auf die Begr & uuml;nungsh & ouml;he waren alle Behandlungen vergleichbar effektiv. Ebenso erfasste die Studie die Wirkung der Ma ss nahmen gegen die Ackerwinde (Convolvulus arvensis), einerseits ein schwer zu bek & auml;mpfbares Weingartenunkraut, zus & auml;tzlich aber noch Zwischenwirt f & uuml;r das Stolbur Phytoplasma ,Candidatus Phytoplasma solani'. Im Vergleich zur unbehandelten Kontrolle wirkten sich alle Ma ss nahmen ung & uuml;nstig auf die Ackerwindendichte im Unterstockbereich aus, am schlechtesten schnitt die Behandlung mittels Hochdruck-Wasserstrahl ab. Insgesamt wurden keine entscheidenden Vorteile der Strom- bzw. Hochdruckstrahlanwendung im Vergleich zu herk & ouml;mmlichen mechanischen Methoden beobachtet. Die vorliegende Studie umfasste zudem Versuche, die Ackerwinde in den Fahrgassen mittels einges & auml;ter Begr & uuml;nung und Stroheinbringung, rund um Weing & auml;rten bzw. am Stra ss enrand auch durch weitgehende Reduktion der Bearbeitung (Langlassen der Begr & uuml;nung) einzud & auml;mmen. Zusammenfassend zeigten die Versuche, dass Konkurrenz und Beschattung durch andere Pflanzenarten die Ackerwindendichte am effektivsten reduzierte. Um den Stolbur-Infektionsdruck f & uuml;r die Reben m & ouml;glichst gering zu halten, ist daher ein Begr & uuml;nungsmanagement, das eine m & ouml;glichst weitgehende Beschattung der Ackerwinde erm & ouml;glicht, anzuraten. Gleichzeitig m & uuml;ssen aber Konkurrenzsituationen zwischen der Rebe und der Begr & uuml;nung, z.B. in Trockenphasen, im Blick behalten werden.

Plant disease outbreaks pose severe risks to global food security. Due to climate change, new diseases are expected to emerge, and the current use of chemical pesticides poses risks to environmental and human health. In the last decade, alternative plant protection agents of microbial origin have been developed, which also raise great expectations in the industry. Current products primarily represent individual microbial strains, either fungi or bacteria, which occasionally fail under field conditions due to various factors while their regulatory status differs globally. Recently, more diverse applications have started to emerge, ranging from microbial consortia, phages and protists to microbiome modulation or soil translocation. Integrated solutions, incorporating artificial intelligence are also proposed. In this review, we discuss the opportunities and challenges of these solutions, providing specific examples and discuss the regulatory needs for their market entry as well as their relevance for improving food security and planetary health.

The application of plant growth-promoting bacteria (PGPB) as bioinoculants is widely recognized for improving crop yields and soil fertility. However, the precise mechanisms underlying their impact on rhizosphere soil quality and crop productivity remain insufficiently understood. This study elucidates how a solid bioinoculant, comprising Bacillus velezensis FZB42 and attapulgite clay, enhances rhizosphere soil quality and maize (Zea mays) growth in nutrient-deficient alkaline calcareous soils. Pot experiments reveal that bioinoculant application promotes extensive root colonization under nitrogen-deficient conditions, with significantly higher colonization rates observed in the half-nitrogen (HN) and zero-nitrogen (ZN) treatments compared to full-nitrogen conditions. Notably, bioinoculant application in ZN and HN significantly increases phosphorus availability and soil quality in the rhizosphere. Furthermore, maize growth parameters, including plant height, stem diameter, and kernel yield, are markedly enhanced, with optimal biomass accumulation achieved under HN conditions. High-throughput sequencing of rhizosphere microbiomes uncovers significant shifts in microbial community composition, with enrichment of key taxa involved in nutrient cycling and plant-microbe interactions. Transcriptomic analysis of maize tissues demonstrates the upregulation of genes associated with nutrient transport, photosynthesis, fatty acid biosynthesis, and kernel development, with a pronounced enrichment in metabolic pathways linked to growth and productivity. Structural equation modeling indicates that increased microbial diversity and gene expression collectively account for 69 % of the variance in the soil quality index and 45 % of the variance in maize yield. These findings provide critical mechanistic insights into the role of solid bioinoculant in enhancing soil fertility and crop performance, highlighting their potential as a sustainable agricultural strategy for improving productivity in low-fertility alkaline soils.

Improved understanding of the complex interaction between plant metabolism, environmental conditions and the plant-associated microbiome requires an interdisciplinary approach: Our hypothesis in our multiomics study posited that several environmental and biotic factors have modulating effects on the microbiome and metabolome of the roots of wild Echium vulgare plants. Furthermore, we postulated reciprocal interactions between the root metabolome and microbiome. We investigated the metabolic content, the genetic variability, and the prokaryotic microbiome in the root systems of wild E. vulgare plants at rosette and flowering stages across six distinct locations. We incorporated the assessment of soil microbiomes and the measurement of selected soil chemical composition factors. Two distinct genetic clusters were determined based on microsatellite analysis without a consistent alignment with the geographical proximity between the locations. The microbial diversity of both the roots of E. vulgare and the surrounding bulk soil exhibited significant divergence across locations, varying soil pH characteristics, and within the identified plant genetic clusters. Notably, acidophilic bacteria were characteristic inhabitants of both soil and roots under acidic soil conditions, emphasizing the close interconnectedness between these compartments. The metabolome of E. vulgare significantly differed between root samples from different developmental stages, geographical locations, and soil pH levels. The developmental stage was the dominant driver of metabolome changes, with significantly higher concentrations of sugars, pyrrolizidine alkaloids, and some of their precursors in rosette stage plant roots. Our study featured the complex dynamics between soil pH, plant development, geographical locations, plant genetics, plant metabolome and microbiome, shedding light on existing knowledge gaps.

Drosophila suzukii Matsumura (Diptera: Drosophilidae) is a polyphagous invasive vinegar fly. Females can penetrate certain soft-skinned grapevine varieties with their strong serrated ovipositor to lay their eggs within berries, which eventually leads to the decay and collapse of grapes. Alternative pest control options were tested in practically oriented field trials set up in two vineyards in Styria. The effect of the mineral particle films diatomaceous earth, kaolin and muscovite mica was compared to an untreated control. All products were complemented with wetting agents to increase the efficacy and/or the rain resistance of the film. Due to the long waiting times after application in organic production, only some of the trials also comprised a comparable insecticide variant (Spinosad). Treatments were applied from the beginning of infestations until harvest, and berries were sampled once to twice a week, depending on pest pressure. Evaluation of treatment effects was based on a microscopic analysis of berries for oviposition and a visual evaluation of the clusters. Both kaolin and diatomaceous earth led to a statistically significant reduction in oviposition and to a significantly improved macroscopic appearance of clusters compared to the control, whereas the effect of muscovite mica was negligible. A direct comparison of particle film and spinosad treatment was only expedient in one experiment, and in this case, the effect of kaolin on oviposition was significantly superior. Kaolin and diatomaceous earth might complement established integrated pest management practices against Drosophila suzukii and contribute to the reduction of chemical plant protection agents in the future.

Ascomycetes, basidiomycetes and deuteromycetes can degrade wood, but less attention has been paid to basidiomycetes involved in Esca, a major Grapevine Trunk Disease. Using a wood sawdust microcosm system, we compared the wood degradation of three grapevine cultivars inoculated with Fomitiporia mediterranea M. Fisch, a basidiomycete responsible for white-rot development and involved in Esca disease. The grapevine cultivar Ugni blanc was more susceptible to wood degradation caused by F. mediterranea than the cultivars Cabernet Sauvignon and Merlot. Solid-state Nuclear Magnetic Resonance (NMR) spectroscopy showed that F. mediterranea preferentially degrades lignin and hemicellulose over cellulose (preferential, successive or sequential white-rot). In addition, co-inoculation of sawdust with two cellulolytic and xylanolytic bacterial strains of Paenibacillus (Nakamura) Ash (Paenibacillus sp. (S231-2) and P. amylolyticus (S293)), enhanced F. mediterranea ability to degrade Ugni blanc. The NMR data further showed that the increase in Ugni blanc sawdust degradation products was greater when bacteria and fungi were inoculated together. We also demonstrated that these two bacterial strains could degrade the wood components of Ugni blanc sawdust. Genome analysis of these bacterial strains revealed numerous genes predicted to be involved in cellulose, hemicellulose, and lignin degradation, as well as several other genes related to bacteria-fungi interactions and endophytism inside the plant. The occurrence of this type of bacteria-fungus interaction could explain, at least in part, why necrosis develops extensively in certain grapevine varieties such as Ugni blanc.

An organism’s observable traits, or phenotype, result from intricate interactions among genes, proteins, metabolites and the environment. External factors, such as associated microorganisms, along with biotic and abiotic stressors, can significantly impact this complex biological system, influencing processes like growth, development and productivity. A comprehensive analysis of the entire biological system and its interactions is thus crucial to identify key components that support adaptation to stressors and to discover biomarkers applicable in breeding programs or disease diagnostics. Since the genomics era, several other ’omics’ disciplines have emerged, and recent advances in high-throughput technologies have facilitated the generation of additional omics datasets. While traditionally analyzed individually, the last decade has seen an increase in multi-omics data integration and analysis strategies aimed at achieving a holistic understanding of interactions across different biological layers. Despite these advances, the analysis of multi-omics data is still challenging due to their scale, complexity, high dimensionality and multimodality. To address these challenges, a number of analytical tools and strategies have been developed, including clustering and differential equations, which require advanced knowledge in bioinformatics and statistics. Therefore, this study recognizes the need for user-friendly tools by introducing Holomics, an accessible and easy-to-use R shiny application with multi-omics functions tailored for scientists with limited bioinformatics knowledge. Holomics provides a well-defined workflow, starting with the upload and pre-filtering of single-omics data, which are then further refined by single-omics analysis focusing on key features. Subsequently, these reduced datasets are subjected to multi-omics analyses to unveil correlations between 2-n datasets. This paper concludes with a real-world case study where microbiomics, transcriptomics and metabolomics data from previous studies that elucidate factors associated with improved sugar beet storability are integrated using Holomics. The results are discussed in the context of the biological background, underscoring the importance of multi-omics insights. This example not only highlights the versatility of Holomics in handling different types of omics data, but also validates its consistency by reproducing findings from preceding single-omics studies.

Bois noir is the most widespread phytoplasma grapevine disease in Europe. It is associated with 'CandidatusPhytoplasma solani'. In symptomatic grapevines cv. 'Zweigelt' infected with 'Ca. P. solani' compared with uninfected grapevines, metabolic pathways associated with phosphorylated sugar production were induced both at the transcriptional level and at the level of activity of the corresponding enzymes (Dermastia et al., 2021, Int. J. Mol. Sci.22: 3531). In particular, the expression of gene coding for phosphoglucoisomerase was upregulated, resulting in increased phosphoglucoisomerase enzyme activity. Phosphoglucoisomerase converse glucose-1-phosphate to glucose-6-phosphate, which can be used as a substrate for starch biosynthesis. Besides, phosphoglucomutase activity was induced also in Nicotiana benthamiana leaves transiently transformed with the construct of putative effector PoStoSP28, previously annotated as an antigenic membrane protein StAMP related to interaction of phytoplasma with its insect vector. Using a pull-down assay and in planta co-IP assay, we confirmed that PoStoSP28 interacts with both grapevine phosphoglucomutases. In transiently transformed N. benthamiana leaves, PoStoSP28 was localized in the nucleus and cytosol and accompanied by a distinct border at the periphery or just outside the nucleus and in the thread-like structures spanning the cells. Upon closer inspection, some autophagosome-like structures were found in N. benthamiana cells expressing the PoStoSP28 effector. Moreover, PoStoSP28 was not only localized in the autophagosome but also increased the occurrence of autophagosomes (Dermastia et al., 2023, Front. Plant Sci. 14: 1232367). Therefore, the results suggest that PoStoSP28 plays a role in the pathogenicity of phytoplasma in grapevine by interacting with grapevine phosphoglucomutase enzymes.

Global research on the plant microbiome has enhanced our understanding of the complex interactions between plants and microorganisms. The structure and functions of plant-associated microorganisms, as well as the genetic, biochemical, physical and metabolic factors that influence the beneficial traits of plant microbiota have also been intensively studied. Harnessing the plant microbiome has led to the development of various microbial applications to improve crop productivity in the face of a range of challenges, for example, climate change, abiotic and biotic stresses, and declining soil properties. Microorganisms, particularly nitrogen-fixing rhizobia as well as mycorrhizae and biocontrol agents, have been applied for decades to improve plant nutrition and health. Still, there are limitations regarding efficacy and consistency under field conditions. Also, the wealth of expanding knowledge on microbiome diversity, functions and interactions represents a huge source of information to exploit for new types of application. In this Review, we explore plant microbiome functions, mechanisms, assembly and types of interaction, and discuss current applications and their pitfalls. Furthermore, we elaborate on how the latest findings in plant microbiome research may lead to the development of new or more advanced applications. Finally, we discuss research gaps to fully leverage microbiome functions for sustainable plant production. In this Review, Compant et al. explore the functions, mechanisms, assembly and interactions of plant microbiomes, highlighting current applications and their limitations. They also discuss how recent advances could lead to new or improved applications and identify research gaps crucial for harnessing microbiome functions in sustainable plant production.

Spotted wing drosophila, Drosophila suzukii Matsumura (Diptera: Drosophilidae), originating from Asia and spreading in Europe since around 2008 has become a major pest of small and stone fruits as well as grapevines in Austria. Due to its enormous reproductive potential, control of this pest is difficult. So far, management is primarily achieved by application of insecticides. However, their application in the field is problematic due to the in many cases short period between infestation and harvest, legally required waiting times, potential residues and side effects on bees and beneficial organisms. Entomopathogenic nematodes have been used to successfully control a wide range of insect pests so far. Therefore, laboratory and field trials were conducted to determine whether nematodes of the species Heterorhabditis bacteriophora and Steinernema feltiae have the potential to interfere with fly development and thus to slow down population growth. In the laboratory experiments, both nematode species significantly reduced the number of hatched adult flies. In the field, adult eclosure was negatively affected by both nematode species, a statistically significant effect, however, was recorded for H. bacteriophora only. The work enlarges the understanding in respect to future management strategies.

Spotted wing drosophila, Drosophila suzukii Matsumura (Diptera: Drosophilidae), originating from Asia and spreading in Europe since around 2008 has become a major pest of small and stone fruits as well as grapevines in Austria. Due to its enormous reproductive potential, control of this pest is difficult. So far, management is primarily achieved by application of insecticides. However, their application in the field is problematic due to the in many cases short period between infestation and harvest, legally required waiting times, potential residues and side effects on bees and beneficial organisms. Entomopathogenic nematodes have been used to successfully control a wide range of insect pests so far. Therefore, laboratory and field trials were conducted to determine whether nematodes of the species Heterorhabditis bacteriophora and Steinernema feltiae have the potential to interfere with fly development and thus to slow down population growth. In the laboratory experiments, both nematode species significantly reduced the number of hatched adult flies. In the field, adult eclosure was negatively affected by both nematode species, a statistically significant effect, however, was recorded for H. bacteriophora only. The work enlarges the understanding in respect to future management strategies. Die Kirschessigfliege, Drosophila suzukii Matsumura (Diptera: Drosophilidae), ist ein invasiver Sch & auml;dling aus Asien, der seit 2008 in Europa auftritt und zu hohen Ertragsausf & auml;llen im Wein-und Obstbau f & uuml;hren kann. Die Eind & auml;mmung erweist sich aufgrund des enormen Reproduktionspotentials als schwierig. Zwar existieren Insektizide, ein Einsatz im Feld ist aufgrund des oft kurzen Zeitraums zwischen Befall und Ernte, gesetzlich vorgeschriebener Wartezeiten nach der Anwendung sowie Auswirkungen auf N & uuml;tzlinge problematisch. Eine Bek & auml;mpfungsm & ouml;glichkeit k & ouml;nnte der Einsatz entomopathogener Nematoden sein, die sich gegen die Larvenentwicklung richten. Mittels Labor- und Freilandexperimenten wurde untersucht, ob Nematoden der Spezies Heterorhabditis bacteriophora und Steinernema feltiae sich dazu eignen, den Bestandsaufbau von Drosophila suzukii zu bremsen. In den Laborversuchen zeigte sich bei Einsatz von H. bacteriophora und S. feltiae eine signifikante Reduzierung der Anzahl geschl & uuml;pfter adulter Fliegen. Auch in einem Freilandversuch in Netzk & auml;figen reduzierten beide Nematodenspezies die Fliegenzahl, ein signifikanter Effekt ergab sich allerdings nur bei H. bacteriophora. Die Arbeit erweitert das Verst & auml;ndnis hinsichtlich m & ouml;glicher eind & auml;mmender Ma ss nahmen gegen die Kirschessigfliege und dient als Grundlage weiterer Forschung zu m & ouml;glichen Bek & auml;mpfungsstrategien.

The pathogenicity of intracellular plant pathogenic bacteria is associated with the action of pathogenicity factors/effectors, but their physiological roles for most phytoplasma species, including ‘ Candidiatus Phytoplasma solani’ are unknown. Six putative pathogenicity factors/effectors from six different strains of ‘ Ca . P. solani’ were selected by bioinformatic analysis. The way in which they manipulate the host cellular machinery was elucidated by analyzing Nicotiana benthamiana leaves after Agrobacterium -mediated transient transformation with the pathogenicity factor/effector constructs using confocal microscopy, pull-down, and co-immunoprecipitation, and enzyme assays. Candidate pathogenicity factors/effectors were shown to modulate plant carbohydrate metabolism and the ascorbate–glutathione cycle and to induce autophagosomes. PoStoSP06, PoStoSP13, and PoStoSP28 were localized in the nucleus and cytosol. The most active effector in the processes studied was PoStoSP06. PoStoSP18 was associated with an increase in phosphoglucomutase activity, whereas PoStoSP28, previously annotated as an antigenic membrane protein StAMP, specifically interacted with phosphoglucomutase. PoStoSP04 induced only the ascorbate–glutathione cycle along with other pathogenicity factors/effectors. Candidate pathogenicity factors/effectors were involved in reprogramming host carbohydrate metabolism in favor of phytoplasma own growth and infection. They were specifically associated with three distinct metabolic pathways leading to fructose-6-phosphate as an input substrate for glycolysis. The possible significance of autophagosome induction by PoStoSP28 is discussed.

Recent outbreaks of ‘ Candidatus Phytoplasma solani’ resulted in severe losses in potatoes, vegetable crops and grapevines in certain regions of Austria and constituted a major challenge for seed potato production. Therefore, the effects of various insecticides and insect deterrents on pathogen spread were studied both in laboratory and field experiments from 2018 to 2021. In laboratory transmission experiments, field captured Hyalesthes obsoletus were caged on differently treated Catharanthus roseus for five days . The insecticides lambda-cyhalothrin, deltamethrin, esfenvalerate, acetamiprid and chlorpyriphos showed the most rapid impact on insect survival and fully prevented phytoplasma transmission. The particle film forming products kaolin and diatomaceous earth had some effect. A transfer of the promising laboratory results to potato fields, however, was achieved to a limited extent only. Treatments with pyrethroids and acetamiprid every 8–10 days over the flight period of H. obsoletus roughly halved the number of symptomatic plants and tubers in case of moderately susceptible varieties and moderate infection pressure. In the event of susceptible varieties and high disease pressure, treatment effects were hardy discernible. In practical terms, the experiments indicate that insecticide applications alone are not sufficient to mitigate the disease. Spraying of diatomaceous earth and mineral oil did not affect disease incidence in the field.

Drosophila suzukii Matsumura (Diptera: Drosophilidae) is a significant pest in soft fruits such as elderberries. Laying of eggs into fruits shortly before harvest results in fruit decay and quick collapse. Practically oriented field trials were set up in three commercial elderberry farms in Styria and Lower Austria from 2018 to 2020 to test alternative, sustainable pest control options. The effect of combinations of diatomaceous earth, paraffin oil, gum arabic, Ca(OH)(2) and maltodextrin with wetting agents based on orange oil/alcohol ethoxylate, polyetherdimethylsiloxanes and terpene oligomers was compared to currently used conventional insecticide treatments (spinosad, lambda-cyhalothrin, acetamiprid) and to an untreated control. Three to five treatments per orchard were applied from the beginning of infestations until harvest. Microscopic analyses of the berries and visual inspections of the umbels allowed evaluation of oviposition, larval development and overall conditions of the umbels for the individual treatments. Diatomaceous earth combined with a wetting agent based on orange oil/alcohol ethoxylate had the most promising effect: the treatment significantly reduced oviposition, reduced instars in berries and improved the conditions of the umbels in all test years as compared to the control. Moreover, Ca(OH)(2) and gum arabic combined with polyetherdimethylsiloxanes lead to a significant reduction of oviposition. Development of flies in the berries was identified as major cause for premature berry drop. These findings may provide a basis for the application of alternative control strategies.

Previous studies have shown that individual, isolated microorganisms may influence secondary metabolism of plants and induce or stimulate the production of medicinally relevant secondary metabolism. Here, we analyzed the microbiome-metabolome linkage of the medicinal plant Alkanna tinctoria , which is known to produce valuable compounds, particularly the naphthoquinones alkannin and shikonin and their derivatives.