Biocontrol agents
Dotaz
Zobrazit nápovědu
elektronický časopis
- Konspekt
- Mikrobiologie
- NLK Obory
- infekční lékařství
- mikrobiologie, lékařská mikrobiologie
- NLK Publikační typ
- elektronické časopisy
There are increasing efforts to identify biocontrol-active microbial metabolites in order to improve strategies for biocontrol of phytopathogens. In this work, Fusarium oxysporum f. sp. conglutinans was confronted with three different biocontrol agents: Trichoderma harzianum, Bacillus amyloliquefaciens, and Pseudomonas aeruginosa in dual culture bioassays. Metabolites produced during the microbial interactions were screened by a matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). T. harzianum exhibited the strongest inhibition of growth of F. oxysporum resulting in overlay of the pathogen colony with its mycelium. Recorded metabolite profiles suggested a direct attack of F. oxysporum mycelium by T. harzianum and B. amyloliquefaciens by means of membrane-attacking peptaibols and a set of antimicrobial lipopeptides and siderophores, respectively. The direct mode of the biocontrol activity of T. harzianum and B. amyloliquefaciens corresponded to their ability to suppress F. oxysporum production of mycotoxin beauvericin suggesting that this ability is not specific only for Trichoderma species. In the case of P. aeruginosa, siderophores pyoverdine E/D and two rhamnolipids were produced as major bacterial metabolites; the rhamnolipid production was blocked by F. oxysporum. The results showed that this type of biocontrol activity was the least effective against F. oxysporum. The effective application of MALDI-MS profiling to the screening of nonvolatile microbial metabolites produced during the interaction of the phytopathogen and the biocontrol microorganisms was demonstrated.
- MeSH
- Bacillus amyloliquefaciens metabolismus fyziologie MeSH
- biologická ochrana * MeSH
- druhová specificita MeSH
- Fusarium růst a vývoj metabolismus MeSH
- glykolipidy metabolismus MeSH
- kokultivační techniky MeSH
- metabolomika MeSH
- mikrobiální interakce MeSH
- mycelium růst a vývoj metabolismus MeSH
- mykotoxiny metabolismus MeSH
- nemoci rostlin mikrobiologie prevence a kontrola MeSH
- Pseudomonas aeruginosa metabolismus fyziologie MeSH
- siderofory metabolismus MeSH
- Trichoderma metabolismus fyziologie MeSH
- Publikační typ
- časopisecké články 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.
- 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
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.
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.
BACKGROUND: Soil microorganisms are key determinants of soil fertility and plant health. Soil phytopathogenic fungi are one of the most important causes of crop losses worldwide. Microbial biocontrol agents have been extensively studied as alternatives for controlling phytopathogenic soil microorganisms, but molecular interactions between them have mainly been characterised in dual cultures, without taking into account the soil microbial community. We used an RNA sequencing approach to elucidate the molecular interplay of a soil microbial community in response to a plant pathogen and its biocontrol agent, in order to examine the molecular patterns activated by the microorganisms. RESULTS: A simplified soil microcosm containing 11 soil microorganisms was incubated with a plant root pathogen (Armillaria mellea) and its biocontrol agent (Trichoderma atroviride) for 24 h under controlled conditions. More than 46 million paired-end reads were obtained for each replicate and 28,309 differentially expressed genes were identified in total. Pathway analysis revealed complex adaptations of soil microorganisms to the harsh conditions of the soil matrix and to reciprocal microbial competition/cooperation relationships. Both the phytopathogen and its biocontrol agent were specifically recognised by the simplified soil microcosm: defence reaction mechanisms and neutral adaptation processes were activated in response to competitive (T. atroviride) or non-competitive (A. mellea) microorganisms, respectively. Moreover, activation of resistance mechanisms dominated in the simplified soil microcosm in the presence of both A. mellea and T. atroviride. Biocontrol processes of T. atroviride were already activated during incubation in the simplified soil microcosm, possibly to occupy niches in a competitive ecosystem, and they were not further enhanced by the introduction of A. mellea. CONCLUSIONS: This work represents an additional step towards understanding molecular interactions between plant pathogens and biocontrol agents within a soil ecosystem. Global transcriptional analysis of the simplified soil microcosm revealed complex metabolic adaptation in the soil environment and specific responses to antagonistic or neutral intruders.
- MeSH
- anotace sekvence MeSH
- ekosystém * MeSH
- exprese genu MeSH
- interakce hostitele a patogenu genetika MeSH
- kořeny rostlin genetika mikrobiologie MeSH
- metagenom MeSH
- metagenomika metody MeSH
- půdní mikrobiologie * MeSH
- shluková analýza MeSH
- stanovení celkové genové exprese MeSH
- transkriptom * MeSH
- výpočetní biologie metody MeSH
- vysoce účinné nukleotidové sekvenování MeSH
- Publikační typ
- časopisecké články MeSH
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.
- MeSH
- antibióza * MeSH
- Bacillus * fyziologie MeSH
- biologická kontrola škůdců * metody MeSH
- biologická ochrana * MeSH
- Citrus mikrobiologie růst a vývoj MeSH
- nemoci rostlin * mikrobiologie prevence a kontrola MeSH
- pektiny metabolismus MeSH
- půdní mikrobiologie MeSH
- Solanum lycopersicum mikrobiologie růst a vývoj MeSH
- vývoj rostlin MeSH
- Publikační typ
- časopisecké články MeSH
Even though pesticides can have various sublethal effects on behaviour of biocontrol agents, no study to date has investigated the effects of pesticides on the prey choice of generalist predators. Prey choice of generalist predators is among key factors determining the predation pressure they exert on pests, because it influences fitness of predators and consequently their densities and per capita capture rate. Here, we investigated the effect of Integro (a.i. methoxyfenozide) and SpinTor 480 Sc (a.i. spinosad) on prey choice and predatory activity of the spider Philodromus cespitum, which is known significantly to reduce hemipteran and dipteran pests in fruit orchards. We compared the prey preferences of philodromids between the psyllid pest Cacopsylla pyri (Hemiptera, Psyllidae) and beneficial Theridion sp. spiders in laboratory experiments. We found that both pesticides altered the prey preferences of philodromids. While the philodromids in a control treatment preferred theridiid spiders over the psyllid pest, philodromids in the pesticide treatments exhibited no significant prey preferences. The changes in prey preferences were caused by increased predation on the psyllids, while the predation on the theridiid remained similar. We suggest that the changes in prey preferences might theoretically be due to 1) impaired sensory systems, 2) altered taste, and/or 3) altered mobility. In combination with other studies finding reduced predation on fruit flies in P. cespitum after exposure to SpinTor, our results indicate that the sublethal effects of pesticides on predatory behaviour of generalist predators can depend on prey type and/or prey community composition.
- MeSH
- Hemiptera MeSH
- insekticidy farmakologie MeSH
- pavouci * MeSH
- predátorské chování účinky léků MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články 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.
- 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
