Biocontrol Dotaz Zobrazit nápovědu
Bacillus is well known for producing a wide range of compounds that inhibit microbial phytopathogens. From this perspective, we were interested in evaluating the biocontrol potential of 5 plant growth-promoting rhizobacteria Bacillus species (PGPR-Bacillus) on 21 microbial pectinolytic plant pathogens isolated from previous studies. Phytopathogenicity and in vivo biocontrol potential of PGPR curative and preventive treatments were investigated from this angle. Overall, the pathogenicity test on healthy tomato, zucchini, and mandarin showed low rot to no symptoms for all PGPR strain culture treatments. Conversely, zucchini pre-treated with PGPR strains B. circulans and B. cereus for 72 h showed no signs of soft rot and remained healthy when in vitro contaminated with phytopathogens (Neisseria cinerea and Pichia anomala). Additionally, the PGPR-Bacillus strains were shown to be effective in mitigating the symptoms of soft rot in tomatoes, zucchini, and oranges using in vivo curative treatment. It is true that the majority of pectinolytic phytopathogenic strains exhibited antibiotic resistance. In vivo tests revealed that PGPR-Bacillus cell culture was effective against plant pathogens. Thus, PGPR-Bacillus can be considered a potential biocontrol agent for pectinolytic plant pathogens.
- Klíčová slova
- Bacillus, Biocontrol, PGPR, Phytopathogenic pectinolytic,
- Publikační typ
- časopisecké články MeSH
The complexities of non-target effects of registered pesticides on biocontrol agents (BCAs) hinder the optimization of integrated pest management programs in agriculture. The wealth of literature on BCA-pesticide compatibility allows for the investigation of factors influencing BCA susceptibility and the generalized impacts of different pesticides. We conducted a meta-analysis using 2088 observations from 122 published articles to assess non-target effects on two phytoseiid species (Neoseiulus californicus and Phytoseiulus persimilis), a parasitoid (Encarsia formosa), and two microbial BCAs (Trichoderma harzianum and Metarhizium anisopliae). We explored the contributions of bioassay factors (exposure duration, temperature, test methods, mode of actions (MOA), and type of pesticide), and simulated effects of compatibility on target pests. MOA groups 21 and 6 were the most harmful to predatory mites and E. formosa, increasing mortality during pesticide-BCA compatibility. Exposure duration, temperature, and test methods were identified as the most influential factors increasing mortality in phytoseiids during pesticide exposure. Insecticides and fungicides were the most represented and harmful groups to BCAs. Although most bioassays were conducted at room temperature, temperatures between 21 and 22 °C were the most harmful to phytoseiids and E. formosa during toxicity assays. Exposure durations of 1-3 days (54-85 %) for predators/parasitoids and 1-5 days (>50 %) for microbial BCAs highlight the lack of data on long-term impacts. In assessing pesticide impacts on target pests, pesticides with compatible concentrations above mean LC50 values were more effective. This study not only identified compatibility trends but also highlighted factors responsible for discrepancies in results and knowledge gaps that need to be addressed.
- Klíčová slova
- Biocontrol agents, Compatibility, Neoseiulus californicus, Pesticides, Phytoseiulus persimilis, Trichoderma,
- MeSH
- biologická kontrola škůdců metody MeSH
- biologická ochrana farmakologie MeSH
- insekticidy farmakologie MeSH
- Metarhizium účinky léků MeSH
- pesticidy * farmakologie toxicita MeSH
- roztoči účinky léků MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- metaanalýza MeSH
- přehledy MeSH
- Názvy látek
- biologická ochrana MeSH
- insekticidy MeSH
- pesticidy * MeSH
Introductions of insect predators and parasitoids for biological control are a key method for pest management. Yet in recent decades, biological control has become more strictly regulated and less frequent. Conversely, the rate of unintentional insect introductions through human activities is rising. While accidental introductions of insect natural enemies can potentially have serious ecological consequences, they are challenging to quantify as their movements go largely unobserved. We used historical border interception records collected by the US Department of Agriculture from 1913 to 2018 to describe the diversity of entomophagous insects transported unintentionally, their main introduction pathways, and trends in host specificity. There were 35,312 interceptions of insect predators and parasitoids during this period, representing 93 families from 11 orders, and 196 species from these families. Commodity associations varied, but imported plants and plant products were the main introduction pathway. Most interceptions originated with commodities imported from the Neotropical, Panamaian, and Western Palearctic regions. Among the intercepted species, 27% were found in material originating from more than one country. Two thirds of species were polyphagous host generalists. Furthermore, 25% of species had already been introduced intentionally as biological control agents internationally, and 4.6% have documented negative impacts on native biodiversity or human society. Most of the intercepted species that have not established in the United States are host generalists or have at least one known host species available. The unintentional transport of diverse natural enemy insects has the potential to cause substantial ecological impacts, both in terms of controlling pests through accidental biocontrol and disrupting native communities. Characterizing the insects being transported and their introduction pathways can inform biosecurity practices and management.
- Klíčová slova
- accidental biocontrol, border interceptions, human‐mediated dispersal, insects, introduction pathways, parasitoids, predators,
- MeSH
- biologická kontrola škůdců * metody MeSH
- hmyz * fyziologie MeSH
- lidé MeSH
- predátorské chování MeSH
- rozšíření zvířat MeSH
- zavlečené druhy MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Spojené státy americké MeSH
Species that belong to the Aphidius eadyi group have been used as biocontrol agents against Acyrthosiphon pisum worldwide. However, despite their extensive use, there are still gaps in our knowledge about their taxonomy and distribution. In this study, we employed an integrative taxonomic approach by combining genetic analyses (mtDNA COI barcoding) with standard morphological analyses and geometric morphometrics of forewing shape. We identified three species within the A. eadyi species group, viz., A. smithi, A. eadyi and A. banksae. Genetic separation of all three species was confirmed, with mean genetic distances between species ranging from 5 to 7.4%. The following morphological characters were determined as the most important for separating species of the A. eadyi group: number and shape of costulae on the anterolateral part of the petiole, shape of the central areola on the propodeum, and shape and venation of the forewings. The differences in wing shape of all three species were statistically significant, but with some overlapping. We identified A. banksae as a widely distributed pea aphid parasitoid, whose known range covers most of the western Palaearctic (from the UK to Israel). Aphidius banksae is diagnosed and redescribed.
- Klíčová slova
- aphid parasitoids, biocontrol agents, geometric morphometrics, mtCOI barcoding,
- MeSH
- biologická ochrana klasifikace MeSH
- druhová specificita MeSH
- křídla zvířecí anatomie a histologie MeSH
- mitochondriální DNA MeSH
- mšice parazitologie MeSH
- sršňovití anatomie a histologie klasifikace genetika MeSH
- taxonomické DNA čárové kódování MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- biologická ochrana MeSH
- mitochondriální DNA MeSH
Three endophytic bacteria, namely BvV, BvP and BvL, were newly isolated from the root nodules of bean, pea and lentil plants respectively cultivated in Mascara the northwest of Algeria, and identified by 16S ribosomal RNA gene sequencing as Brevundimonas naejangsanensis. These strains were able to produce hydrolytic enzymes and hydrogen cyanide. All strains produced a growth-promoting hormone, indole acetic acid, varying in concentration from 83.2 to 171.7 µg/mL. The phosphate solubilizing activity of BvV, BvP and BvL varied from 25.5 to 42.02 µg/mL for tricalcium phosphate. The three antagonistic Brevundimonas spp. showed in vitro the most inhibitory effect on mycelial growth of Fusarium redolens FRC (from 78.33 to 85.55%). Strain BvV, BvP and BvL produced also volatile metabolites which inhibited mycelial FRC growth up to 39.2%. All strains showed significant disease reduction in pot experiments. Chickpea Fusarium yellows severity caused by FRC was reduced significantly from 89.3 to 96.6% in the susceptible cultivar ILC 482 treated with antagonistic B. naejangsanensis. The maximum stimulatory effect on chickpea plants growth was observed by inoculation of strain BvV. This treatment resulted in a 7.40-26.21% increase in shoot height as compared to the control plants. It is concluded that the endophytic bacterial strains of B. naejangsanensis having different plant growth promoting (PGP) activities can be considered as beneficial microbes for sustainable agriculture. To our knowledge, this is the first report to use B. naejangsanensis strains as a new biocontrol agent against F. redolens, a new pathogen of chickpea plants causing Fusarium yellows disease in Algeria.
- Klíčová slova
- Brevundimonas naejangsanensis, Fusarium redolens, Antagonistic activities, Biocontrol, Plant growth promoting,
- MeSH
- antibióza * MeSH
- biologická ochrana farmakologie MeSH
- Burkholderiales genetika růst a vývoj metabolismus MeSH
- Cicer * mikrobiologie růst a vývoj MeSH
- endofyty izolace a purifikace genetika klasifikace fyziologie metabolismus MeSH
- fosfáty metabolismus MeSH
- Fusarium * růst a vývoj fyziologie genetika MeSH
- fylogeneze MeSH
- kořeny rostlin mikrobiologie MeSH
- kyseliny indoloctové metabolismus MeSH
- nemoci rostlin * mikrobiologie prevence a kontrola MeSH
- regulátory růstu rostlin metabolismus MeSH
- RNA ribozomální 16S * genetika MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Alžírsko MeSH
- Názvy látek
- biologická ochrana MeSH
- fosfáty MeSH
- indoleacetic acid MeSH Prohlížeč
- kyseliny indoloctové MeSH
- regulátory růstu rostlin MeSH
- RNA ribozomální 16S * MeSH
Rhizobia are a group of organisms that are well known for their ability to colonize root surfaces and form symbiotic associations with legume plants. They not only play a major role in biological nitrogen fixation but also improve plant growth and reduce disease incidence in various crops. Rhizobia are known to control the growth of many soilborne plant pathogenic fungi belonging to different genera like Fusarium, Rhizoctonia, Sclerotium, and Macrophomina. Antagonistic activity of rhizobia is mainly attributed to production of antibiotics, hydrocyanic acid (HCN), mycolytic enzymes, and siderophore under iron limiting conditions. Rhizobia are also reported to induce systemic resistance and enhance expression of plant defense-related genes, which effectively immunize the plants against pathogens. Seed bacterization with appropriate rhizobial strain leads to elicitation and accumulation of phenolic compounds, isoflavonoid phytoalexins, and activation of enzymes like L-phenylalanine ammonia lyase (PAL), chalcone synthase (CHS), peroxidase (POX), polyphenol oxidase (PPO), and others involved in phenylpropanoid and isoflavonoid pathways. Development of Rhizobium inoculants with dual attributes of nitrogen fixation and antagonism against phytopathogens can contribute to increased plant growth and productivity. This compilation aims to bring together the available information on the biocontrol facet of rhizobia and identify research gaps and effective strategies for future research in this area.
Three hundred and seventy two isolates belonging to the genus Streptomyces were isolated and screened for chitinase production. Streptomyces plicatus was found to be the best producer. The highest chitinase production were incubated for 3 d at 30 degrees C on buffered culture medium (pH 8.0) containing chitin plus sucrose and calcium nitrate as carbon and nitrogen sources. S. plicatus chitinase had a highly significant inhibitory effect on spore germination, germ tube elongation and radial growth of Fusarium oxysporum f.sp. lycopersici, Altrernaria alternata and Verticillium albo-atrum, the causal organisms of Fusarium wilt, stem canker and Verticillium wilt diseases of tomato. Application of S. plicatus to the root system of tomato plants before transplantation markedly protected tomato plants against the tested phytopathogenic fungi in vivo.
- MeSH
- Alternaria růst a vývoj MeSH
- biologická kontrola škůdců * MeSH
- chitinasy metabolismus MeSH
- Fusarium růst a vývoj MeSH
- nemoci rostlin mikrobiologie MeSH
- Solanum lycopersicum mikrobiologie MeSH
- Streptomyces klasifikace enzymologie růst a vývoj MeSH
- Verticillium růst a vývoj MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
- Názvy látek
- chitinasy MeSH
Plant beneficial microbes mediate biocontrol of diseases by interfering with pathogens or via strengthening the host. Although phytohormones, including cytokinins, are known to regulate plant development and physiology as well as plant immunity, their production by microorganisms has not been considered as a biocontrol mechanism. Here we identify the ability of Pseudomonas fluorescens G20-18 to efficiently control P. syringae infection in Arabidopsis, allowing maintenance of tissue integrity and ultimately biomass yield. Microbial cytokinin production was identified as a key determinant for this biocontrol effect on the hemibiotrophic bacterial pathogen. While cytokinin-deficient loss-of-function mutants of G20-18 exhibit impaired biocontrol, functional complementation with cytokinin biosynthetic genes restores cytokinin-mediated biocontrol, which is correlated with differential cytokinin levels in planta. Arabidopsis mutant analyses revealed the necessity of functional plant cytokinin perception and salicylic acid-dependent defence signalling for this biocontrol mechanism. These results demonstrate microbial cytokinin production as a novel microbe-based, hormone-mediated concept of biocontrol. This mechanism provides a basis to potentially develop novel, integrated plant protection strategies combining promotion of growth, a favourable physiological status and activation of fine-tuned direct defence and abiotic stress resilience.
- MeSH
- Arabidopsis mikrobiologie MeSH
- cytokininy analýza biosyntéza farmakologie MeSH
- kyselina salicylová farmakologie MeSH
- listy rostlin mikrobiologie MeSH
- nemoci rostlin mikrobiologie MeSH
- Pseudomonas fluorescens metabolismus MeSH
- Pseudomonas syringae účinky léků růst a vývoj patogenita MeSH
- regulátory růstu rostlin farmakologie MeSH
- tandemová hmotnostní spektrometrie MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- cytokininy MeSH
- kyselina salicylová MeSH
- regulátory růstu rostlin MeSH
Confocal laser-scanning microscopy was chosen to observe the colonization and damage caused by the soft rot Pectobacterium atrosepticum and the protection mediated by the biocontrol agent Rhodococcus erythropolis. We developed dual-color reporter strains suited for monitoring quorum-sensing and quorum-quenching activities leading to maceration or biocontrol, respectively. A constitutively expressed cyan or red fluorescent protein served as a cell tag for plant colonization, while an inducible expression reporter system based on the green fluorescent protein gene enabled the simultaneous recording of signaling molecule production, detection, or degradation. The dual-colored pathogen and biocontrol strains were used to coinoculate potato tubers. At cellular quorum, images revealed a strong pectobacterial quorum-sensing activity, especially at the plant cell walls, as well as a concomitant rhodococcal quorum-quenching response, at both the single-cell and microcolony levels. The generated biosensors appear to be promising and complementary tools useful for molecular and cellular studies of bacterial communication and interference.
Conidia production of Beauveria sp. strain LAG by solid-state fermentation (SSF) using blends of agro-industrial residues (residual potatoes and sugar-cane bagasse) was optimized with respect to cultivation conditions and the composition of substrate mixture in Erlenmeyer flasks and column-type bioreactor. With a blend of 60 % residual potatoes and 40 % sugar-cane bagasse the optimum conditions achieved were: incubation temperature 26 degrees C, initial substrate pH 6, inoculum concentration 10(7) conidia per g substrate; optimal initial moisture of the substrate was 70 % for Erlenmeyer flasks, in column-type bioreactor (with forced aeration) the optimal initial moisture of the substrate was 65 % with airflow of 60 mL/min. The highest production (1.07 x 10(10) conidia per g dry substrate) was achieved after a 10-d fermentation. The conidia were used in laboratory assays against Thelosia camina and Hylesia sp., caterpillars that are serious pests of mate plants. The mortality of T. camina was >90 % 10 d after spraying caterpillars with 1 mL conidia suspension at a concentration 10(5)-10(8)/mL. For Hylesia sp., the mortality was 70 %, 7 d after immersion in the conidia suspension containing 108 conidia per mL. Therefore, the Beauveria sp. LAG can be considered to be an important biocontrol instrument in the prospect of the Integrated Pest Management for mate plants.
