Bacterial Antagonists Research Articles

Molecular characterization of selected fungal and bacterial endophytes in acid lime

Endophytes are the microorganisms that are present in living tissue of various plant parts (roots, fruits, stem, seed, leaf etc,). Endophytic microorganisms are good source of antibiotics. Endophytic antagonists were isolated from the roots of healthy acid lime plants collected from major acid lime growing areas of Andhra Pradesh. A total of 8 fungal and 10 bacterial endophytic antagonists were isolated. The antagonists were further subjected to preliminary screening, out of which only 6 endophytic fungal antagonists (EFA 1-6) and 8 endophytic bacterial antagonists (EBA 1-8) isolates showed good inhibitory effect on radial growth of Fusarium solani causing dry root rot in acid lime in vitro. Among them the one of the best fungal and bacterial antagonists that were found to be extremely efficient against Fusarium solani in dual culture assay were selected for further molecular identification. The BLAST results revealed that one of the fungal isolate had shown 100% similarity with Aspergillus fumigatus and one of the bacterial isolate had shown 95.56% similarity with Pseudomonas aeruginosa.

Management of Root-Knot Nematode on Okra through Bio-Agents

A pot study was conducted to assess the efficacy of various fungal and bacterial antagonists as seed coating treatments against Meloidogyne javanica, a root-knot nematode that infects okra plants. The seeds of okra cv. Pusa Sawani were subjected to treatments with Trichoderma viride, Purpureocillium lilacinum, and Pseudomonas fluorescens at a rate of 2 g/kg seed. As a comparison, Carbosulfan 3G was used as a control, applied at a rate of 3g/kg soil. The treated seeds were then planted in soil infested with two second-stage juveniles of the root -knot nematode per gram of soil. After 45 days of sowing, it was observed that the okra plants exhibited enhanced growth, while the population of root-knot nematodes was significantly reduced in all treatment groups compared to the untreated control. Among the different bio agents tested, Purpureocillium lilacinum exhibited the best treatment followed by Trichoderma viride and Pseudomonas fluorescens for increase plant growth characters as well as reduced nematode reproduction.

Перспективные штаммы антагонисты возбудителя фомоза на подсолнечнике: оценка фитотоксичности и ростостимулирующей активности

The phytotoxicity and growth stimulating activity of promising strains antagonists of a Phoma pathogen on sunflower seedlings were estimated. Soaking of sunflower seeds and seedlings in suspensions of fungi and bacteria-antagonists did not have a depressing effect on seed germination and wilting of seedlings. Three bacterial strains antagonists from a genus Bacillus: 5-3, K 1-2, and 5B-1 Bacillus sp., and two strains from a genus Pseudomonas: Oif 2-1 and 14-3 Pseudomonas sp. showed the maximal authentic increase (by 10.0–14.0%) in seed germination (94.0–98.0% at germination in a control 84.0%). Only two fungal strains antagonists: Xk-1 Chaetomium sp. and A-1 Basidiomycota, showed verifiable increase (by 6%) in seed germination (90%). The verifiable stimulating effect of antagonists on root weight was stated. The bacterial strains 11-1, D-10, and 5-3 Bacillus sp. (150.0–166.7%) and fungal ones Xk-1 Chaetomium sp. and Pbc-1 Penicillium sp. (133.3–150.0%) showed the best results comparing to the control.

Evaluation of Trichoderma harzianum, Bacillus subtilis and Aspergillus species efficacy in controlling Pythium ultimum associated with apple seedlings decline in nurseries and their growth promotion effect

BackgroundApple decline diseases, responsible for seedlings root and collar rot in nurseries, are an important disease. Different fungal and bacterial antagonists were evaluated to control Pythium ultimum associated with this serious disease using in vitro and in vivo greenhouse assays.ResultsThe in vitro test of ten Aspergillus spp. and ten Trichoderma harzianum isolates showed their efficacy to reduce the radial growth of P. ultimum. The isolates, A. niger A10, A. candidus A5, T. harzianum Tr9 and Tr10, were the most effective with a high inhibition percent that exceeded 50%. The in vivo test of the four most effective antagonists and a strain of Bacillus subtilis (B) showed that the combination of the two Aspergillus isolates (A5 and A10) gave the best result with a decrease in root browning index by 55.55%. Results showed also the efficacy of all tested antagonists and their combinations on the sanitary state index of the inoculated plants except the combination between T. harzianum (Tr10) and B. subtilis (B). The two treatments, T. harzianum (Tr10) and B. subtilis (B), significantly improved the height of inoculated plants by 173.19 and 191.3%, respectively. Regarding the efficacy of antagonists on apple seedlings root weight, A. niger (A10) was the only treatment that significantly increased this parameter by 363.17%.ConclusionsA. niger A10, A. candidus A5, T. harzianum Tr9 and Tr10 exhibited the highest value of in vitro inhibition to growth of P. ultimum. The combination of A. niger A10 and A. candidus A5 was the most effective in vivo treatment in reducing the disease severity index. However, T. harzianum (Tr10), B. subtilis (B) and A. niger (A10) revealed to be able to stimulate the apple seedlings growth.

Antagonistic potential of rhizobacterial isolates against fungal pathogens causing rhizome rot in turmeric.

The study aims to select potent bacterial antagonists to be used as biocontrol agents against rhizome rot disease in turmeric (Curcuma longa L.). A total of 48 bacterial isolates were isolated from the rhizosphere of turmeric. These isolates were screened for their in vitro antagonism against Fusarium solani FS-01 and Pythium aphanidermatum (ITCC 7908). Production of volatile organic compounds and chitinase activity were also performed. Among the tested isolates, two bacterial isolates (IJ2 and IJ10) showed the highest inhibitory activity against these fungal pathogens. GC/MS analysis of the crude extract produced by Pseudomonas sp. IJ2 and B. subtilis IJ10 was found to contain many bioactive compounds with antifungal and antimicrobial activities. The rhizome treatment with these isolates exhibited the lowest percent disease severity with high biocontrol efficacy against the tested pathogens. These isolates with promising antagonistic potential, therefore, can be used as biocontrol agents against rhizome rot in turmeric.

Field Evaluation of the Efficacy of Fungicides and Rhizosphere Bacterial Antagonists against Rice Stem Rot Disease

Rice stem rot disease in paddy cultivation leads to reduction of yield. Management of this disease is difficult as it is soil borne. In the present study, field trials were conducted during Rabi 2016-17 and early Kharif 2017-18 to assess the effectiveness of twelve fungicides and four rhizosphere bacterial antagonistic isolates (RRB-1 to RRB-4) against rice stem rot disease. Disease incidence was recorded from the date of initial incidence of the disease i.e., once in 15 days from maximum tillering to panicle emergence. Pooled analysis reveals that Hexaconazole recorded lowest per cent disease index (32.22) with highest grain yield and straw yield of 7.43 t/ha and 7.22 t/ha respectively, followed by Difenoconazole with grain yield and straw yield of 7.29 t/ha and 6.88 t/ha respectively. On the other hand, bacterial antagonists using root dipping and foliar spray with RRB-4 showed less PDI of 32.92 with grain yield of 6.97 t/ha and straw yield of 6.61 t/ha. With this study, hexaconazole (0.2%) and bacterial antagonists RRB-4 using root dipping and foliar spray (105 to 106 CFU/ml) can be effectively managed the rice stem rot.

Screening bacterial isolates for biocontrol of sheath blight in rice plants

Sheath blight (Rhizoctonia solani) causes significant yield losses in rice (Oryza sativa L.). Its sustainable management needs an efficient biocontrol agent. The objective was to screen bacterial isolates as an antagonist to R. solani and identify the most efficient ones as sheath blight suppressors under greenhouse conditions. Two assays (E1 and E2) were performed in a completely randomized design with three replications. E1 tested 21 bacterial isolates antagonists to R. solani in vitro. E2 was conducted under greenhouse conditions, with rice cultivar BRS Pampeira sown in plastic pots (7 kg) containing fertilized soil. Sixty old plants were inoculated with a segment of a toothpick containing fragments of R. solani, followed by spray inoculation of a bacterial suspension (108 CFU/mL). The severity of the disease was determined by calculating the relative lesion size formed on the colm. Isolates BRM32112 (Pseudomonas nitroreducens), BRM65929 (Priestia megaterium), and BRM65919 (Bacillus cereus) reduced R. solani colony radial growth by 92.8, 77.56, and 75.56%, respectively while BRM63523 (Serratia marcescens), BRM65923 and BRM65916 (P. megaterium) and BRM65919 (B. cereus) with 23.45, 23.37, 23.62, and 20.17 cm, respectively were effective at suppressing sheath blight in greenhouse, indicating their potential as a biofungicide for sheath blight suppression.

A novel cyanolytic bacterium, Pseudomonas fluorescens BG-E as a potential biological control agent for freshwater bloom-forming cyanobacteria Pseudanabaena spp.

The majority of bacterial antagonists identified to date are active against Microcystis. Therefore, this study aimed to isolate and characterize novel cyanolytic bacterial strains antagonistic against bloom-forming filamentous cyanobacteria. The bacterial strain BG-E isolated from the Bandagiriya Wewa in Sri Lanka was identified as Pseudomonas fluorescens (MZ007859) based on the 16S rRNA gene sequencing. BG-E showed 82% and 73% cyanolytic activity (CA) against Pseudanabaena sp. LW2 (MW288948) and Pseudanabaena lonchoides LW1 (MW288940), respectively, after 10 days of inoculation. The light microscopic images affirmed the complete disintegration in the filamentous structures of the tested Pseudanabaena species. The bacterial cell density of 15% v/v showed the CA with 95% and 89% cell lysis, respectively, in P. lonchoides and Pseudanabaena sp. LW2. Moreover, the results showed that >50% CA could be achieved by 0.100 and 1.00 (OD730 ) cell densities for these same species. The highest CA of the cell-free supernatant of BG-E against P. lonchoides and bacterial culture against Pseudanabaena sp. LW2 illustrated the species-specific mode of action of BG-E. Although BG-E efficiently lysed the tested cyanobacterial species, the results of the MC-biodegradation assay confirmed its inability to degrade MC-LR cyanotoxin. Further, the BG-E strain lacks the mlrABCD gene cluster which is known to be responsible for the enzymatic degradation of MCs. The overall findings highlighted the applicability of P. fluorescens BG-E as a biological controlling agent to terminate blooms of freshwater filamentous cyanobacteria genus Pseudanabaena. The incorporation of cyanotoxin-degrading heterotrophic bacteria is recommended as a means of controlling toxic Pseudanabaena blooms.

Significant antimicrobial-producing vegetation uniquely shapes the stormwater biofilter microbiome with implications for enhanced faecal pathogen inactivation

Biofilters demonstrate promising yet inconsistent removal of faecal pathogens from stormwater. Antimicrobial-producing plants represent safe, inexpensive biofilter design features which can significantly enhance faecal microbe treatment. The microbiota naturally inhabiting biofilters have additionally been established as key mediators of faecal microbe inactivation. To date, however, it remains unknown: (1) to what extent plants, including significant antimicrobial-producing plants, influence the biofilter microbiome; and (2) how this in turn impacts faecal microorganism survival/die-off. The present study employed 16S rRNA sequencing to examine these relationships throughout the soil profiles of differently vegetated biofilters over time. It was found that plants had subtle but significant influences on the composition and structure of resident biofilter bacterial communities, with varying impacts observed throughout biofilter profiles. Bacterial communities inhabiting biofilters comprising significant antimicrobial-producing plants demonstrated distinct compositional and taxonomic differences relative to other configurations. In particular, compared to other biofilters, the best-performing configuration for faecal bacterial treatment, Melaleuca linariifolia (significant antimicrobial-producing plant), exhibited both higher and lower relative frequencies of putative faecal bacterial antagonists (e.g. Actinobacteria) and mutualists (e.g. certain Gammaproteobacteria), respectively. These preliminary findings suggest that antimicrobial plants may enhance populations of microbiota which suppress faecal bacterial survival, and highlight the plant-microbiome relationship as a novel area of focus for optimising biofilter performance.

The coral microbiome: Towards an understanding of the molecular mechanisms of coral-microbiota interactions.

Corals live in a complex, multi-partite symbiosis with diverse microbes across kingdoms, some of which are implicated in vital functions, such as those related to resilience against climate change. However, knowledge gaps and technical challenges limit our understanding of the nature and functional significance of complex symbiotic relationships within corals. Here, we provide an overview of the complexity of the coral microbiome focusing on taxonomic diversity and functions of well-studied and cryptic microbes. Mining the coral literature indicate that while corals collectively harbor a third of all marine bacterial phyla, known bacterial symbionts and antagonists of corals represent a minute fraction of this diversity and that these taxa cluster into select genera, suggesting selective evolutionary mechanisms enabled these bacteria to gain a niche within the holobiont. Recent advances in coral microbiome research aimed at leveraging microbiome manipulation to increase coral's fitness to help mitigate heat stress-related mortality are discussed. Then, insights into the potential mechanisms through which microbiota can communicate with and modify host responses are examined by describing known recognition patterns, potential microbially-derived coral epigenome effector proteins and coral gene regulation. Finally, the power of omics tools used to study corals are highlighted with emphasis on an integrated host-microbiota multiomics framework to understand the underlying mechanisms during symbiosis and climate change-driven dysbiosis.

Biological Control Efficacy of Indigenous Antagonistic Bacteria Isolated from the Rhizosphere of Cabbage Grown in Biofumigated Soil against Pythium aphanidermatum Damping-Off of Cucumber

Soil biofumigation is a widely used farming practice for soil-borne disease management in vegetable crops. Soil biofumigation is the practice of the incorporation of fresh plant materials from the members of the Brassicaceae family into the soil which release antimicrobial volatile organic compounds (VOCs), namely glucosinolates and their hydrolysis products. However, the VOCs may affect non-target beneficial soil biota including microbial biocontrol agents (MBAs) due to their broad-spectrum toxicity. In this study, native antagonistic rhizobacteria were isolated from cabbage plants grown in biofumigated fields and their potential in the management of Pythium aphanidermatum cucumber damping-off was evaluated with and also without biofumigation using cabbage leaf residue. A total of 20 morphologically distinct, culturable bacterial strains were recovered from the rhizosphere soil of cabbage cultivated in a biofumigated field, with the largest fraction of the isolates belonging to the genus Bacillus. The other bacterial genera isolated were Pseudomonas, Serratia, Stenotrophomonas, Microbacterium and Priestia. Of the 20 bacterial isolates, Pseudomonas aeruginosa B1-SQU, Pseudomonas indica B2-SQU, Serratia marcescens B3-SQU and Pseudomonas brenneri B4-SQU exhibited inhibitory activity against P. aphanidermatum in a co-culture assay. The deformation and shrinkage of P. aphanidermatum hyphae due to diffusible antimicrobial compounds from these bacterial strains were witnessed through scanning electron microscopy. A biofilm was formed by these bacterial strains in vitro and they exhibited compatibility with each other; however, they had no significant plant growth promotion effect on cucumber. These bacterial strains significantly reduced damping-off in cucumber under greenhouse conditions when applied to soil singly, but failed to show a significant effect when combined with biofumigation treatment, though the bacterial population in the soil was maintained at higher levels. Soil biofumigation alone was also not effective in suppressing the damping-off of cucumber. Gas chromatography–mass spectrometry analysis revealed that 1-butanol, n-butyl butyrate and butyl acetate were the predominant VOCs in the soil amended with cabbage leaf residue. The results suggest that soil biofumigation with cabbage leaf residue has no significant effect on P. aphanidermatum under high inoculum levels; furthermore, it affects the efficiency of the bacterial antagonists in controlling damping-off in cucumber.

Efficacy Of Fungicides And Bioagents Against Seed Borne Fungi Of Wheat

Wheat is an important cereal crop of Indian agriculture and food security system. Seed borne diseases have been found to have an impact on wheat crop plant growth and productivity. Assessment and management of wheat seed borne fungi is an important. A. alternata, C. lunata, D. tetramera, B. sorokiniana were detected and isolated from seed samples by standard blotter paper method. Fungicides were tested in vitro against wheat seed borne fungi using the poisoned food technique. Tebuconazole (0.1%), Carbendazim + Mancozeb (0.25%) and Carboxin + Thiram (0.3%) were found most to be the most effective fungicides, inhibiting 100% of the mycelial growth of all associated seed-borne fungi, followed by Azoxystrobin + Difenoconazole (0.1%). Bioagents were also tested against wheat seed-borne fungi using a dual culture technique, and the results revealed that the fungal bioagent Trichoderma harzianum was found most effective against seed borne fungi, followed by Trichoderma asperellum. Bacterial antagonists were found to be less effective than fungal antagonists.

Assessing The In Vitro Efficacy Of Agrochemicals And Antagonist Against Major Seed Borne Fungi Of Pearl Millet

The significant millet crop grown in India is pearl millet, which has a slightly superior amino acid profile and is high in protein. Using blotter paper, four seed-borne fungus were isolated: Alternaria alternata, Curvularia penniseti, Bipolaris setariae, and Fusarium moniliforme. The fungicides and antagonists were then assessed using the poisoned food and dual culture techniques, respectively. Tebuconazole (0.1%), Copper oxychloride (0.25%) were found most effective fungicides over all other treatments for arresting the mycelial growth (100%) of all associated seed borne fungi followed by combi product Carbendazim + Mancozeb (0.25%). The most efficient fungal bioagent against seed-borne fungus among the antagonists was Trichoderma asperellum, followed by Trichoderma harzianum. In comparison to fungal antagonists, bacterial antagonists Bacillus subtilis and Pseudomonas fluorescence were shown to be less potent.

Potential Impacts of Eminent Fungicide, Certain Bacterial and Fungal Antagonists for Controlling Cercospora Leaf Spot Disease in Sugar Beet.

Potential Impacts of Eminent Fungicide, Certain Bacterial and Fungal Antagonists for Controlling Cercospora Leaf Spot Disease in Sugar Beet.

Bacillus cereus B8W8 an effective bacterial antagonist against major postharvest fungal pathogens of fruit

The antifungal activity of Bacillus cereus (B8W8) was investigated against major post-harvest fungal pathogens affecting citrus and apples fruits namely Penicillium digitatum, Penicillium italicum, Geotrichum citri-aurantii, Penicillium expansum, Botrytis cinerea, Monilinia laxa and Monilinia fructigena. The in vitro dual culture of B8W8 and fungal pathogens showed high inhibition rates of the mycelial growth of Monilinia laxa and Penicillium digitatum (71.4% and 72.5% respectively). Subsequently, the volatile compounds (VOCs) have a high antagonistic effect against Monilinia laxa (86.4%) and Monilinia fructigena (73.4%). In addition, the bacterial-free cell filtrate of B8W8 had a significantly important effect on the inhibition of spore’s germination and mycelial growth of Penicillium expansum, Botrytis cinerea, Penicillium italicum and Geotrichum citri-aurantii. The in vivo bioassays revealed a significant impact of B8W8 on fruit decays either by reducing the disease severity of causative agents or by completely preventing their occurrence, particularly brown rot of apple caused by M. laxa and green mold of citrus caused by P. digitatum (DS = 0%). However, the severity of sour rot of citrus caused by G. citri-aurantii was only reduced by 50%. The semi-commercial trials showed a high potential of B. cereus B8W8 to reduce the incidence of gray mold of apple and green mold of citrus to very low values during at storage. In addition, the biological treatment with B8W8 was shown generally more effective than imazalil, the chemical treatment reference. Furthermore, the rapid colonization of fruit wounds by B8W8 could promote its antagonistic ability. Moreover, biochemical tests showed the ability of B8W8 to produce protease, amylase, and hydrocyanic acid (HCN). Interestingly, the molecular analysis demonstrated the ability of this bacterium to produce the fengycin. The secretion of this lipopeptide and lytic enzymes is more likely the major mechanism of action involved in the biocontrol activity of this bacterium. Results indicated that quality parameters of fruit, when challenged post-harvest pathogens and treated with B8W8, were mostly very close to those of the untreated control, suggesting that B8W8 did not affect the fruit quality. Accordingly, it was concluded that B. cereus strain B8W8 could be an effective biological agent to control the main fungal pathogens of apples and citrus fruits during post-harvest period.

Study of the efficacy of bacterial antagonists against Cadophora luteo-olivacea of kiwifruit

Skin pitting currently represents one of the major postharvest diseases of kiwifruit and one of the most difficult to manage in packinghouses due to its latent behavior and the difficulty in predicting its emergence. Our research demonstrates the potential to use different bacterial strains (Pseudomonas synxantha and Bacillus spp.) instead of synthetic compounds to preserve kiwifruit from the development of postharvest skin pitting symptoms, following the momentum towards sustainable strategies. The antagonists tested with in vitro assays showed different efficacy rates against C. luteo-olivacea (strain Cad21) mycelial growth by producing non-volatile metabolites. The biochemical composition of the most active bacterial non-volatile secondary metabolites was described through FT-IR (Fourier-Transform Infrared) spectroscopy. Pseudomonas synxantha strain 117-2b emerged as the most active strain in in vivo experiments, both as a curative and preventive treatment (63% and 84.7% of inhibition, respectively). In addition to its ability to reduce disease incidence, the biological antagonism exerted by P. synxantha strain 117-2b was further demonstrated by qPCR analysis as a reduction in the pathogen's abundance. In view of these results, alternative solutions in the field and during postharvest storage could be considered to control C. luteo-olivacea of kiwifruit.

Enhancing bioefficacy of Bacillus amyloliquefaciens SF14 with salicylic acid for the control of the postharvest citrus green mould

Penicillium digitatum is a major post-harvest pathogen of citrus fruit causing tremendous economic losses. In this study, salicylic acid (SA) and antagonistic bacteria Bacillus amyloliquefaciens (SF14) were tested in controlling P. digitatum (green mould) infections as an alternative to chemical controls. Three concentrations of SA (0.5, 1, and 2%) were tested for their antifungal activity in both in vitro and in vivo conditions alone and in combination with SF14. Fruit quality parameters including fruit firmness, weight loss, titratable acidity, and soluble solids content were evaluated. The impact of these biological treatments was also investigated by measuring the changes in organic and mineral properties of orange fruits using Fourier transform infrared spectroscopy (FT-IR). Enzymatic activity including phenylalanine ammonia-lyase (PAL), total polyphenols and flavonoids was also tested. In vitro assays showed that SF14 combined with 0.5% SA provided the highest inhibition of green mould growth reaching 72.98%. Inhibition of spore germination was also highest in the same treatment od reaching 63.40%. FTIR of fungal biomass confirmed an alteration of fungal well wall following biological treatments. Moreover, during in vivo assays, the combination of SF14 and 0.5% SA produced the lowest disease severity (5.43%) without considerably affecting the fruit quality. Further investigation of the effect of these treatments on the mineral composition of treated oranges showed that Ca, Fe, K, Mg, and Na concentrations were significantly affected. Changes in these elements may show a defence reaction induced by the biological treatments against the pathogen, which was also confirmed with the measurement of PAL activity, total polyphenols, and flavonoids. Interestingly, FTIR of citrus peel indicated significant changes in the content of bands denoting for phenolic and aromatic rings, suggesting an induced resistance against the pathogenic fungus. Overall, our findings suggested that the combination of both bacterial antagonist SF14 and 0.5% SA can control the green mould of citrus, and as such constitutes a safer alternative to chemicals during postharvest storage.

The Effectiveness Comparison Between Application of Indigenous Arbuscular Mycorrhizal Fungal Community and Stenotrophomonas maltophilia to Suppress Fusarium Wilt Incidence on Local Garlic Plant (Lumbu Hijau)

Wilt disease caused by Fusarium oxysporum is one of the most serious plant diseases in the world. There is no effective contol for. This study investigated the potential of arbuscular mycorrhizal and bacterial antagonists to control F. oxysporum through in vitro and in vivo studies. In this study, the antagonistic bacteria Stenotrophomonas maltophilia was isolated from mycorrhizal propagation media. Antagonist bacteria S. maltophilia showed antagonistic ability against F. oxysporum with an inhibition zone of 17.9 cm. Antagonistic bacteria and mycorrhizae used in this study significantly reduced the incidence of fusarium wilt in in vivo experiments. It was found that mycorrhizal and S. maltophilia inoculation showed disease incidence rates at 40% and 47.6%. While in the control treatment the incidence of disease reached 90.3%. The biocontrol agents of S. maltophilia and mycorrhizae have a promising prospective strategy to protect garlic plants. These results are expected to provide new insights for sustainable crop protection systems.

Biological control of Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. by epiphytic bacteria isolated from Vitis vinifera (cv Thompson Seedless) grape berry

ABSTRACT Anthracnose leaf spot and ripe rot disease, caused by Colletotrichum gloeosporioides in India, is of economic importance. The objective of the investigation was to isolate and characterise bacterial antagonists from the grape berry surface. Nine bacteria out of the 46 that were isolated significantly inhibited C. gloeosporioides in a dual culture assay. Six of these nine microorganisms demonstrated pathogen inhibition by producing extracellular volatile and non-volatile compounds. Bacteria SB5, SB13, and SB15 were chosen for the polyhouse experiment because they demonstrated the best disease control in a detached leaf assay. At 1 × 106 CFU/ml of bacterial concentration, both curative and preventive trials showed significant disease inhibition. Based on morphological and molecular characterisation the bacteria were identified as Bacillus species. All three strains could be effectively used for the biological control of C. gloeosporioides.

Bacteriobiota of the Cave Church of Sts. Peter and Paul in Serbia—Culturable and Non-Culturable Communities’ Assessment in the Bioconservation Potential of a Peculiar Fresco Painting

The principal aim of this study was to determine bacterial diversity within the Cave Church of Sts. Peter and Paul, via culturable and non-culturable approaches, and elucidate the antifungal potential of autochthonous antagonistic bacterial isolates against biodeteriogenic fungi. Furthermore, whole-genome sequencing of selected bacterial antagonists and the analysis of genes included in the synthesis of secondary metabolites were performed. With the highest RA values, determined in metabarcoding analysis, phyla Actinobacteriota (12.08-54.00%) and Proteobacteria (25.34-44.97%) dominated most of the samples. A total of 44 different species, out of 96 obtained isolates, were determined as part of the culturable bacteriobiota, with the predominance of species from the genus Bacillus. Bacillus simplex was the only isolated species simultaneously present in all investigated substrata within the church. The best antagonistic activity against 10 biodeteriogenic fungi was documented for Streptomyces anulatus, followed by Bacillus altitudinis, Chryseobacterium viscerum, and Streptomyces sp. with their highest PGI% values ranging of from 55.9% to 80.9%. These promising results indicate that characterized bacteria are excellent candidates for developing biocontrol strategies for suppressing deteriogenic fungi responsible for the deterioration of investigated fresco painting. Finally, isolate 11-11MM, characterized as Streptomyces sp., represents a new species for science prompting the need for further study.