The study aimed to assess the potential of phyllospheric bacterial strains isolated from cauliflower plants as biocontrol agents against black rot disease caused by Xanthomonas campestris pv. campestris, through both in vitro and in vivo evaluations. A total of 46 bacterial strains were isolated from healthy and infected cauliflower leaves of both resistant and susceptible plants, and evaluated them for various traits, including plant growth-promoting activities and in vitro antagonistic activity against Xanthomonas campestris pv. campestris. Further, a pot experiment was conducted with the susceptible cauliflower genotype (Pusa Sharad) and 10 selected phyllospheric bacterial isolates to assess their biocontrol efficacy against the disease. The results showed that 82.60% of phyllospheric bacterial isolates were positive for phosphate solubilization, 63.04% for ammonia production, 58.69% for HCN production, 36.95% for siderophore production, and 78.26% had the capacity to produce IAA. Out of the 46 isolates, 23 exhibited in vitro antagonistic activity against X. campestris pv. campestris and 10 isolates were selected for a pot experiment under glasshouse conditions based on their good plant growth-promoting activities and antagonistic assay. The results revealed that bacterial isolate CFLB-27 exhibited the highest biocontrol efficiency (65.41%), followed by CFLB-24 (58.30%), CFLB-31 (47.11%), and CFLB-26 (46.03%). These four isolates were identified as Pseudomonas fluorescens CFLB-27, Bacillus velezensis CFLB-24, Bacillus amyloliquefaciens CFLB-31, and Stenotrophomonas rhizophila CFLB-26. This study provides valuable insights into the potential of phyllospheric bacteria as an effective tool for disease management in sustainable agriculture.
- MeSH
- antibióza * MeSH
- Bacteria klasifikace izolace a purifikace genetika růst a vývoj MeSH
- biologická ochrana MeSH
- Brassica * mikrobiologie MeSH
- listy rostlin * mikrobiologie MeSH
- nemoci rostlin * mikrobiologie prevence a kontrola MeSH
- Xanthomonas campestris * genetika růst a vývoj MeSH
- Publikační typ
- časopisecké články MeSH
The synchronous research and analysis of total and active soil microbial communities can provide insight into how these communities are impacted by continuous cropping years and pathogen infection. The diversity of total and active bacteria in rhizospheric soil of 2-year-old and 3-year-old healthy and diseased Panax notoginseng can comprehensively reveal the bacterial response characteristics in continuous cropping practice. The results showed that 4916 operational taxonomic units (OTUs) were found in the rhizospheric soil bacterial community of P. notoginseng at the DNA level, but only 2773 OTUs were found at the RNA level. The rhizospheric environment had significant effects on the active and bacterial communities, as indicated by the number of OTUs, Shannon, Chao1, Faith's phylogenetic diversity (Faith's PD), and Simpson's diversity indexes. The DNA level can better show the difference in diversity level before and after infection with root rot. The bacterial Chao1 and Faith's PD diversity indexes of 2-year-old root rot-diseased P. notoginseng rhizospheric soil (D2) were higher than that of healthy plants, while the bacterial Shannon diversity index of 3-year-old root rot-diseased P. notoginseng rhizospheric soil (D3) was the lowest in the total bacteria. Principal coordinate analysis (PCoA) illustrated that the total bacterial species composition changed markedly after root rot disease. There were significant differences in the composition of active bacterial species between the 2-year and 3-year rhizospheres. In conclusion, the total and active edaphic rhizospheric bacterial communities could provide important opportunities to understand the responses of bacteria to continuous cropping of P. notoginseng.
- MeSH
- Bacteria * klasifikace genetika izolace a purifikace MeSH
- biodiverzita * MeSH
- DNA bakterií genetika MeSH
- fylogeneze * MeSH
- kořeny rostlin mikrobiologie MeSH
- nemoci rostlin mikrobiologie MeSH
- Panax notoginseng * mikrobiologie MeSH
- půda chemie MeSH
- půdní mikrobiologie * MeSH
- rhizosféra * MeSH
- RNA ribozomální 16S genetika MeSH
- Publikační typ
- časopisecké články MeSH
Grey mold, caused by Botrytis cinerea, is a widespread and harmful disease of tomato. Biocontrol agents derived from endophytic bacteria are known to hold great potential for inhibition of phytopathogen. We conducted this study to explore the tomato endophytic strains with inhibition activity against B. cinerea. Endophytic strain Bacillus velezensis FQ-G3 exhibited excellent inhibition activity against B. cinerea. Inhibitory effects against B. cinerea were investigated both in vitro and in vivo. The in vitro assays displayed that FQ-G3 could significantly inhibit mycelia growth with inhibition rate of 85.93%, and delay conidia germination of B. cinerea. Tomato fruit inoculated with B. velezensis FQ-G3 revealed lower grey mold during treatment. The antifungal activity was attributed to activation of defense-related enzymes, as evidenced by the higher levels of peroxidase, polyphenol oxidase, and phenylalanine ammonia lyase in tomatoes after inoculation. In addition, scanning electron microscope was applied to elucidate the interaction between endophytes and pathogen, and bacterial colonization and antibiosis appeared to be the underlying mechanisms that FQ-G3 could suppress growth of B. cinerea. Collectively, our present results suggested that FQ-G3 may potentially be useful as a biocontrol agent in postharvest tomatoes.
Ganoderma sp., the fungal agent causing basal stem rot (BSR), poses a severe threat to global oil palm production. Alarming increases in BSR occurrences within oil palm growing zones are attributed to varying effectiveness in its current management strategies. Asymptomatic progression of the disease and the continuous monoculture of oil palm pose challenges for prompt and effective management. Therefore, the development of precise, early, and timely detection techniques is crucial for successful BSR management. Conventional methods such as visual assessments, culture-based assays, and biochemical and physiological approaches prove time-consuming and lack specificity. Serological-based diagnostic methods, unsuitable for fungal diagnostics due to low sensitivity, assay affinity, cross-contamination which further underscores the need for improved techniques. Molecular PCR-based assays, utilizing universal, genus-specific, and species-specific primers, along with functional primers, can overcome the limitations of conventional and serological methods in fungal diagnostics. Recent advancements, including real-time PCR, biosensors, and isothermal amplification methods, facilitate accurate, specific, and sensitive Ganoderma detection. Comparative whole genomic analysis enables high-resolution discrimination of Ganoderma at the strain level. Additionally, omics tools such as transcriptomics, proteomics, and metabolomics can identify potential biomarkers for early detection of Ganoderma infection. Innovative on-field diagnostic techniques, including remote methods like volatile organic compounds profiling, tomography, hyperspectral and multispectral imaging, terrestrial laser scanning, and Red-Green-Blue cameras, contribute to a comprehensive diagnostic approach. Ultimately, the development of point-of-care, early, and cost-effective diagnostic techniques accessible to farmers is vital for the timely management of BSR in oil palm plantations.
Potato scab is a common potato tuber disease that affects quality and cost in the marketplace, shortening storage, and increasing the chance for secondary infection. The tubers with disease severity of 1 to 4 are accepted and stored in potato storage for cheap selling in Thailand. However, there are few studies of the bacterial community of the scabby tuber during storage. Thus, we aim to elucidate the diversity, structure, and function of the bacterial community of 30-day storage potato scabby tubers stored in different temperatures using 16S amplicon metagenomic sequencing. Bacterial communities of storage potato scabby tubers (Spunta cultivar) collected from different storage temperatures, 4 °C (MEP1) and 6 °C (MEP2), were characterized using 16S rRNA amplicon metagenomic sequencing. The alpha-diversity abundance in the bacteriome of the scabby tubers stored at 6 °C was higher than in those stored at 4 °C. Actinobacteria (34.7%) was a dominant phylum in MEP1, while Proteobacteria (39.9%) was predominant in MEP2. The top 10 genera of both communities were Rhizobium group, Streptomyces, Pectobacterium, Ruminococcus, Cellulomonas, Promicromonospora, Prevotella, Enterobacter, Pedobacter, and Paenarthrobacter. Moreover, functional profile prediction of both communities reveals essential genes in the pathosystem: nos, bglA, and cebEFG-msiK for potato scab disease and phc and peh operons for rot disease. Our findings are the first study to explore details of the bacteriome of the accepted potato scabby tubers for selling during storage in Thailand and strongly indicate that although potatoes were stored at low temperatures, diseases still occur by secondary pathogens.
- MeSH
- Bacteria * genetika klasifikace izolace a purifikace MeSH
- biodiverzita MeSH
- DNA bakterií genetika MeSH
- fylogeneze MeSH
- hlízy rostlin * mikrobiologie MeSH
- metagenomika MeSH
- mikrobiota MeSH
- nemoci rostlin * mikrobiologie MeSH
- RNA ribozomální 16S * genetika MeSH
- skladování potravin * MeSH
- Solanum tuberosum * mikrobiologie MeSH
- teplota MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Thajsko MeSH
Autophagy, an intracellular degradation process, has emerged as a crucial innate immune response against various plant pathogens, including viruses. Tomato spotted wilt orthotospovirus (TSWV) is a highly destructive plant pathogen that infects over 1000 plant species and poses a significant threat to global food security. However, the role of autophagy in defence against the TSWV pathogen, and whether the virus counteracts this defence, remains unknown. In this study, we report that autophagy plays an important role in antiviral defence against TSWV infection; however, this autophagy-mediated defence is counteracted by the viral effector NSs. Transcriptome profiling revealed the up-regulation of autophagy-related genes (ATGs) upon TSWV infection. Blocking autophagy induction by chemical treatment or knockout/down of ATG5/ATG7 significantly enhanced TSWV accumulation. Notably, the TSWV nucleocapsid (N) protein, a major component of the viral replication unit, strongly induced autophagy. However, the TSWV nonstructural protein NSs was able to effectively suppress N-induced autophagy in a dose-dependent manner. Further investigation revealed that NSs inhibited ATG6-mediated autophagy induction. These findings provide new insights into the defence role of autophagy against TSWV, a representative segmented negative-strand RNA virus, as well as the tospoviral pathogen counterdefence mechanism.
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
Biocontrol fungi are widely used to promote plant growth and pest control. Four fungi were isolated from Cremastra appendiculata tubers and screened for plant growth-promoting and antagonistic effects. Based on the morphological characterization and ITS, 18S rRNA and 28S rRNA gene sequencing analysis, the fungi were identified to be related to Colletotrichum gloeosporioides (DJL-6), Trichoderma tomentosum (DJL-9), Colletotrichum godetiae (DJL-10) and Talaromyces amestolkiae (DJL-15). The growth inhibition tests showed that the four isolates had different inhibitory effects on Colletotrichum fructicola, Alternaria alternata and Alternaria longipes, among which DJL-9 showed the highest inhibitory activity. Their culture filtrates (especially that of DJL-15) can also inhibit pathogens. Four isolates were positive for the production of indole-3-acid (IAA) and β-1,3-glucanase and possessed proteolytic activity but were negative for the production of iron siderophore complexes. The four fungi showed strong nitrogen fixation and potassium dissolution abilities. In addition to DJL-9 being able to solubilize phosphate, DJL-10 was able to produce chitinase and cellulase. Pot experiments indicated that the four fungi increased the germination rate of C. appendiculata and soybean seeds and increased soybean radicle growth and plant biomass. Among them, DJL-6 had a better growth-promoting effect. Therefore, we successfully screened the biocontrol potential of endophytes from C. appendiculata, with a focus on preventing fungal diseases and promoting plant growth, and selected strains that could provide nutrients and hormones for plant growth.
- MeSH
- endofyty MeSH
- fosfáty MeSH
- houby * MeSH
- nemoci rostlin mikrobiologie MeSH
- semena rostlinná MeSH
- vývoj rostlin * MeSH
- Publikační typ
- časopisecké články MeSH
Disease-suppressive soils encompass specific plant-pathogen-microbial interactions and represent a rare example of an agroecosystem where soil conditions and microbiome together prevent the pathogen from causing disease. Such soils have the potential to serve as a model for characterizing soil pathogen-related aspects of soil health, but the mechanisms driving the establishment of suppressive soils vary and are often poorly characterized. Yet, they can serve as a resource for identifying markers for beneficial activities of soil microorganisms concerning pathogen prevention. Many recent studies have focused on the nature of disease-suppressive soils, but it has remained difficult to predict where and when they will occur. This review outlines current knowledge on the distribution of these soils, soil manipulations leading to pathogen suppression, and markers including bacterial and fungal diversity, enzymes, and secondary metabolites. The importance to consider soil legacy in research on the principles that define suppressive soils is also highlighted. The goal is to extend the context in which we understand, study, and use disease-suppressive soils by evaluating the relationships in which they occur and function. Finally, we suggest that disease-suppressive soils are critical not only for the development of indicators of soil health, but also for the exploration of general ecological principles about the surrounding landscape, effects of deeper layers of the soil profile, little studied soil organisms, and their interactions for future use in modern agriculture.
Phytopathology is a highly complex scientific discipline. Initially, its focus was on the study of plant-pathogen interactions in agricultural and forestry production systems. Host-pathogen interactions in natural plant communities were generally overlooked until the 1970s when plant pathologists and evolutionary biologists started to take an interest in these interactions, and their dynamics in natural plant populations, communities, and ecosystems. This article introduces the general principles of plant pathosystems, provides a basic critical overview of current knowledge of host-pathogen interactions in natural plant pathosystems, and shows how this knowledge is important for future developments in plant pathology especially as it applies in cropping systems, ecology, and evolutionary biology. Plant pathosystems can be further divided according to the structure and origin of control, as autonomous (wild plant pathosystems, WPPs) or deterministic (crop plant pathosystems, CPPs). WPPs are characterized by the disease triangle and closed-loop (feedback) controls, and CPPs are characterized by the disease tetrahedron and open-loop (non-feedback) controls. Basic general, ecological, genetic, and population structural and functional differences between WPPs and CPPs are described. It is evident that we lack a focus on long-term observations and research of diseases and their dynamics in natural plant populations, metapopulations, communities, ecosystems, and biomes, as well as their direct or indirect relationships to CPPs. Differences and connections between WPPs and CPPs, and why, and how, these are important for agriculture varies. WPP and CPP may be linked by strong biological interactions, especially where the pathogen is in common. This is demonstrated through a case study of lettuce (Lactuca spp., L. serriola and L. sativa) and lettuce downy mildew (Bremia lactucae). In other cases where there is no such direct biological linkage, the study of WPPs can provide a deeper understanding of how ecology and genetics interacts to drive disease through time. These studies provide insights into ways in which farming practices may be changed to limit disease development. Research on interactions between pathosystems, the "cross-talk" of WPPs and CPPs, is still very limited and, as shown in interactions between wild and cultivated Lactuca spp.-B. lactucae associations, can be highly complex. The implications and applications of this knowledge in plant breeding, crop management, and disease control measures are considered. This review concludes with a discussion of theoretical, general and specific aspects, challenges and limits of future WPP research, and application of their results in agriculture.
