Effective Biocontrol Research Articles

NezhNPV, a new biocontrol agent for Nesodiprion zhejiangensis Zhou & Xiao (Hymenoptera: Diprionidae), an emerging forest pest.

Nesodiprion zhejiangensis, a multivoltine sawfly, is widely distributed in south China and has caused serious damage to forests. Historically, N. zhejiangensis management has relied heavily on synthetic chemicals. To reduce the reliance on chemical control, we previously isolated a nucleopolyhedrovirus, NezhNPV, from deceased N. zhejiangensis larvae. A subsequent pathogenicity assay confirmed its high virulence in a laboratory setting. In order to comprehensively examine the hypothesis that NezhNPV is an effective new biocontrol agent for N. zhejiangensis, we carried out a field test in Beijing, China, and characterized NezhNPV morphologically by electron microscopy and genetically by genome sequencing. Our field trials showed that NezhNPV was effective in controlling N. zhejiangensis in a naturally infested Himalayan blue pine forest. The occlusion bodies of NezhNPV consist of irregular polyhedra that occlude rod-shaped enveloped virions with a single nucleocapsid per virion. The NezhNPV genome is 80 637 bp in length, and contains 90 open reading frames, including 38 core, eight lepidopteran baculovirus, 34 hymenopteran baculovirus and 10 unique baculovirus genes, representing the smallest known genome among baculoviruses. The combined results based on phylogenetic analyses, Kimura-2-parameter distances and biological characteristics indicate that NezhNPV is a novel gammabaculovirus and candidate for species status with the provisional name Gammabaculovirus nezhejiangensis. NezhNPV is highly collinear with other gammabaculoviruses and contains nonsyntenic regions with an inversion and rearrangement between orf3 and orf35. The combined results from our field trials, coupled with morphological and genomic characterization clearly demonstrate the bioactivity of NezhNPV. This gammabaculovirus may be included in pest management practices against N. zhejiangensis as a novel biocontrol agent. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Antibacterial, Herbicidal, and Plant Growth-Promoting Properties of Streptomyces sp. STD57 from the Rhizosphere of Adenophora stricta

Bacterial wilt triggered by the soil-borne pathogenic bacterium Ralstonia solanacearum is one of the most serious diseases in tomato plants, leading to huge economic losses worldwide. Biological control is considered an environmentally friendly and sustainable way to manage soil-borne diseases. In this study, Streptomyces sp. STD57 isolated from the rhizosphere of Adenophora stricta showed strong antibacterial activity against R. solanacearum. Pot experiments showed that strain STD57 exhibited a significant biocontrol effect (81.7%) on tomato bacterial wilt in the greenhouse environment. Furthermore, strain STD57 could inhibit the growth of weeds (Amaranthus retroflexus, Portulaca oleracea, and Echinochloa crusgalli) but promote the growth of crops (wheat, rice, and tomato). The plant growth-promoting substance was identified as indoleacetic acid (IAA) by high-pressure liquid chromatography–mass spectrometry and genome analysis. Coarse separation of the fermented extracts revealed that the antibacterial and herbicidal substances were mainly in the fermentation supernatant and belonged to different products. These findings suggested that strain STD57 may be a potential biocontrol and bioherbicide agent useful in agriculture.

Isolation, identification, characterization and in vitro assay of saline tolerant endophytes against groundnut root rot caused by Rhizoctonia bataticola (Taub.) Butler

Groundnut, known as Arachis hypogaea L., is India's significant oil seed crop. Dry root rot, caused by Rhizoctonia bataticola, poses a substantial challenge to cultivating groundnuts. During the roving survey, 60.50% dry root rot disease incidence was recorded in Namakkal district, Tamil Nadu. This study aims to acquire salt-tolerant endophytic bacteria residing in groundnuts with significant antagonistic activity against R. bataticola. A total of 27 bacterial strains were isolated from groundnuts. Among these strains, RMV 3 and RMV 2 are the most effective isolates, exhibiting 60.1% and 50% inhibition zones, respectively. The effective isolates were characterized through morphological, biochemical and phytostimulation activities and 16S rDNA sequencing. Among the isolates, RMV 3 and RMV 2 showed positive results for siderophore, indole acetic acid (IAA) and cellulase test. The strain RMV 3 was identified as Bacillus subtilis through 16S rDNA sequencing. GC-MS analysis identified twenty bioactive compounds produced by B. subtilis RMV 3, such as pyrrolo [12-a] pyrazine-14-dione hexahydro-3 (2-methylpropyl) and hexadecanoic acid methyl ester. The crude metabolite assay demonstrated a 96.6% inhibition of R. bataticola by RMV 3. This study demonstrated that Bacillus subtilis RMV 3, which exhibits a robust antagonistic effect on R. bataticola, can potentially be an effective biocontrol agent for groundnut dry root rot.

Olfactory response to HIPVs and biological aspects of Chrysoperla externa intended for the biological control of Aleurodicus cocois in cashew

ABSTRACT This study evaluates the olfactory response of Chrysoperla externa to the volatiles of the Embrapa 51 genotype of the cashew induced by the herbivory of Aleurodicus cocois, identifies the chemical profile of these compounds and evaluates the development of C. externa fed on A. cocois. The volatiles emitted by the leaves of the cashew genotype, both infested and not infested with A. cocois, were analysed by solid-phase microextraction with GC-MS. In the olfactometry tests, C. externa was attracted to and spent more time in the olfactometer arm containing cashew plant volatiles induced by A. cocois. From the analysis of the volatile profiles, α-phellandrene, α-terpinene, ρ-mentha-2,4(8)-diene, β-caryophyllene and germacrene D were released in large amounts by the Embrapa 51 genotype only after infestation by A. cocois; these compounds may therefore be involved in attracting the predator. Under laboratory conditions, although the development time and survival of some immature stages of C. externa may vary with the type of prey, when fed on A. cocois, the predator is able to complete the egg-adult development cycle. Based on the behavioural and biological assays, C. externa is an effective biocontrol agent for A. cocois in the cashew.

Biocontrol Efficacy of Bacillus thuringiensis Strain 00-50-5 Against the Root-Knot Nematode Meloidogyne enterolobii in Pepper

The root-knot nematode Meloidogyne enterolobii is a major constraint to pepper production in tropical regions. In the long-term practice of root-knot nematode management, bacterial nematicides have attracted increasing attention as effective biocontrol agents. In this study, we evaluated the efficacy of Bacillus thuringiensis strain 00-50-5 (Bt 00-50-5) against M. enterolobii through in vitro, greenhouse and field trials. The cell-free supernatant of Bt 00-50-5 exhibited potent nematicidal activity against second-stage juveniles (J2s) of M. enterolobii, with mortality rates of 98.0% and 100% after 24 h and 36 h of exposure, respectively. In addition, Bt 00-50-5 showed inhibitory effects on the hatching of M. enterolobii eggs, resulting in a remarkable 96.6% reduction in the egg hatching rate after 6 days compared to the control. The pot trials showed that both pepper root galls and egg masses were reduced, and plant growth was improved after treatment with Bt 00-50-5. The field trials showed that the gall index was significantly reduced, with a 66.3% and 68.2% reduction in disease index in 2020–2021 and 2021–2022, respectively, and pepper yield was improved, with a 96.2% and 93.1% increase in yield in 2020–2021 and 2021–2022, respectively, compared to the control. These results indicate the potential use of Bt 00-50-5 as an effective biocontrol agent against M. enterolobii.

Molecular interactions of Trichoderma: from microbial competition to soil health promotion

The increasing demand for sustainable solutions to agricultural pest and disease management has positioned Trichoderma fungi as a promising biological control agent. Trichoderma is not only capable of suppressing various plant pathogens but also promotes plant growth and strengthens natural plant defenses. This mini-review explores the molecular mechanisms underlying Trichoderma's ability to function as a biocontrol agent, focusing on nutrient competition, antibiotic production, mycoparasitism, and the induction of plant resistance. Additionally, advances in genomics and transcriptomics have facilitated a deeper understanding of the signaling pathways and genes responsible for Trichoderma's biocontrol effectiveness, including G-protein and MAPK pathways. Beyond pathogen suppression, Trichoderma plays a key role in enhancing soil health and establishing symbiotic relationships with plants, contributing to improved nutrient absorption and growth hormone production. However, challenges remain in translating laboratory success to large-scale field applications. This mini review highlights the need for further research on optimizing Trichoderma formulations, understanding its interaction with other beneficial soil organisms, and exploring genetic engineering to enhance its biocontrol capabilities. The future of Trichoderma lies in its integration into holistic, agroecological systems alongside other sustainable pest management strategies.

Influence of Enhanced Synthesis of Exopolysaccharides in Rhizobium ruizarguesonis and Overproduction of Plant Receptor to these Compounds on Colonizing Activity of Rhizobia in Legume and Non-Legume Plants and Plant Resistance to Phytopathogenic Fungi.

Rhizobial exopolysaccharides (EPS) may provide stabilization of membranes against external factors, as well as improved surface adhesion, but their role in interaction with legume and non-legume plants is still far from understanding. In this work, the transcriptional regulator RosR of Rhizobium ruizarguesonis, which regulates the synthesis of EPS, was overproduced in a pHC60 plasmid and expressed in the RCAM 1026 strain. This resulted in an improved production of EPS by this recombinant strain. Comparative analysis of the inoculation of pea Pisum sativum plants with R. ruizarguesonis pHC60-rosR and strain carrying the empty plasmid revealed an essential increase in the number of nodules, root length and biomass in plants inoculated with this EPS-overproducing strain. It demonstrates that the enhanced EPS synthesis by rhizobia may stimulate plant root colonization and subsequent nodule formation in pea plants. The influence of enhanced EPS synthesis in rhizobia on colonizing activity was also estimated in non-legume plant tomato Solanum lycopersicum. Our findings shown the increased colonization of the root surface and stimulation of the shoot biomass of inoculated plants. Inoculation of pea and tomato with EPS-overproducing rhizobial strain essentially increased plant resistance to phytopathogenic fungi Fusarium culmorum and F. oxysporum in both legume and non-legume plants, demonstrating a significant biocontrol effect of this recombinant strain. Furthermore, we have identified the PsLYK10 gene that encodes a putative EPS receptor in P. sativum, although no significant effect of PsLYK10 overexpression on nodulation in legume (pea P. sativum) and colonization of roots of non-legume plants by rhizobia was found compared to enhanced production of EPS by rhizobia.

Biocontrol Efficacy of Pseudomonas Consortia Against Botrytis Blight in Petunias.

Botrytis cinerea, a fungal pathogen causing Botrytis blight, significantly impacts greenhouse crop management due to its broad host range and infection capabilities at various growth stages. Traditional control methods, primarily reliant on fungicides, are challenged by environmental concerns and the rise of fungicide-resistant strains. This study investigates the use of beneficial Pseudomonas bacteria as a sustainable alternative. We hypothesized that specific Pseudomonas consortia could provide more effective biocontrol of B. cinerea than individual strains. Our research investigated five Pseudomonas strains (14B11, AP54, 15H3, 94G2, and 89F1) known to reduce Botrytis blight in Petunia × hybrida. Compatibility for bacterial consortia was assessed through biofilm formation and direct bacterial inhibition assays. The biocontrol effects of the bacteria against B. cinerea were investigated in vitro using shared-air space dual culture assays and in planta by inoculating detached petunia flowers. We found strain 14B11 exhibited the highest biofilm formation, with consortia of 14B11 and 89F1 showing significant enhancement compared to individual cultures, while a slight, non-significant increase was observed in 14B11 and AP54 consortia. However, strain 14B11 efficacy was inhibited by strain 15H3. Genomic analyses identified antifungal compound-related gene clusters in 14B11 and AP54, contributing to their biocontrol potential. Trials with detached flowers of Petunia × hybrida 'Carpet Red Bright' confirmed significant disease severity reduction with 14B11, AP54, and their consortia. This research highlights strategic Pseudomonas consortia as promising, eco-friendly alternatives to chemical fungicides, promoting sustainable agriculture by enhancing our understanding of how microbial interactions can be used to manage Botrytis blight.

Endophyte Bacillus vallismortis BL01 to Control Fungal and Bacterial Phytopathogens of Tomato (Solanum lycopersicum L.) Plants

Some strains of Bacillus vallismortis have been reported to be efficient biocontrol agents against tomato pathogens. The aim of our study was to assess the biocontrol ability of the endophytic strain BL01 Bacillus vallismortis through in vitro and field trials, as well as to verify its plant colonization ability and analyze the bacterial genome in order to find genes responsible for the biocontrol activity. We demonstrated in a gnotobiotic system and by confocal laser microscopy that the endophytic strain BL01 was able to colonize the endosphere and rhizosphere of tomato, winter wheat and oilseed rape. In vitro experiments demonstrated the inhibition activity of BL01 against a wide range of phytopathogenic fungi and bacteria. BL01 showed biological efficacy in two-year field experiments with tomato plants against black bacterial spotting by 40–70.8% and against late blight by 47.1% and increased tomato harvest by 24.9% or 10.9 tons per hectare compared to the control. Genome analysis revealed the presence of genes that are responsible for the synthesis of biologically active secondary metabolites, which could be responsible for the biocontrol action. Strain BL01 B. vallismortis can be considered an effective biocontrol agent to control both fungal and bacterial diseases in tomato plants.

Enhancing biocontrol efficacy of Cryptococcus laurentii induced by carboxymethyl cellulose: Metabolic pathways and enzyme activities insights

The synergistic biocontrol effects of Cryptococcus laurentii cultured with carboxymethyl cellulose (CMC) were studied to control Penicillium italicum in postharvest grapefruit. The results showed that C. laurentii was cultured in 0.5 % (w/v) CMC (CMC-C. laurentii) significantly inhibited elongation of germ tubes, decreased germination of conidia in P. italicum, and reduced disease in grapefruit. Besides, CMC significantly increased ATP synthase and population proliferation of C. laurentii. Moreover, metabolomics analysis revealed 24 significantly differentially metabolites in CMC-C. laurentii including the citrate cycle, metabolism of glyoxylic acid, dicarboxylic acid, phenylalanine, tyrosine, and tryptophan and amino acid biosynthesis. These results demonstrate that CMC could significantly enhance the ATP synthase by promoting the citrate cycle, providing energy for strain growth, and thereby increasing the biocontrol effectiveness of C. laurentii. Furthermore, adding CMC enhanced the activities of strain extracellular hydrolases and antioxidases, which increased the resistance to stress, thus improving the antagonistic effect of C. laurentii.

A novel K57-specific Klebsiella pneumoniae phage disinfects milk and inhibits biofilm formation

Klebsiella pneumoniae (K. pneumoniae), especially serotype K57, is a major pathogen in dairy bovine mastitis, causing significant economic losses and posing a public health risk through contaminated dairy products. In addition, K57 is highly virulent among serotypes infecting humans, leading to serious conditions such as pyogenic liver abscess. In this study, we isolated and identified a bacteriophage called vB_Kp_Z57 that targets K57 serotype K. pneumoniae isolates from human and bovine sources. The phage has a latent period of 4 min and can produce approximately 233 phages per infected bacterial cell. vB_Kp_Z57 is stable over a temperature range of 4 °C to 60 °C and a pH range of 5–11. Sequencing and assembly of the phage genome revealed DNA molecules consisting of 40,316 base pairs. After genome annotation with bioinformatics software, it was discovered that the phage genome encodes 48 proteins, with no detected lysogeny genes, toxin genes, or tRNA-related genes. vB_Kp_Z57 was classified as a member of genus Przondovirus, family Autographiviridae. The results of bacteriostatic experiments show that vB_Kp_Z57 has a good effect on inhibiting bacterial growth. Notably, vB_Kp_Z57 significantly inhibited the growth of its host bacteria in milk at refrigerated temperatures of 4 °C and room temperature. Biofilm inhibition experiments revealed that phage vB_Kp_Z57 significantly reduced OD595 values in all phage-treated groups, indicating its potential as an effective biocontrol agent against K. pneumoniae. Our findings show the promise of vB_Kp_Z57 as a novel and environmentally friendly solution to address the challenges associated with K. pneumoniae in dairy production.

New Trichoderma Strains Suppress Blue Mold in Oranges by Damaging the Cell Membrane of Penicillium italicum and Enhancing Both Enzymatic and Non-Enzymatic Defense Mechanisms in Orange Fruits

Blue mold disease, caused by Penicillium italicum (P. italicum), presents a significant challenge to orange fruits (Citrus sinensis L.) and other citrus crops globally. Biological control, particularly Trichoderma species, offers a promising alternative to synthetic fungicides. Therefore, this study aimed to isolate, identify, and evaluate the antagonistic activities of two Trichoderma isolates against P. italicum. These isolates were molecularly identified and assigned accession numbers PP002254 and PP002272, respectively. Both isolates demonstrated significant antifungal activity in dual culture assays. Moreover, the culture filtrates (CFs) of Trichoderma longibrachiatum PP002254 and Trichoderma harzianum PP002272 suppressed the mycelial growth of P. italicum by 77.22% and 71.66%, respectively. Additionally, CFs reduced the severity of blue mold on orange fruits by 26.85% and 53.81%, compared to 100% in the control group. Scanning electron microscopy revealed that treated P. italicum hyphae were shrunken and disfigured. Enzyme activities (catalase, peroxidase, polyphenol oxidase, and phenylalanine ammonia-lyase) in treated oranges increased, along with total soluble phenolics and flavonoids. Conversely, malondialdehyde (MDA) levels decreased in treated fruits. These findings suggest that T. longibrachiatum PP002254 and T. harzianum PP002272 could be effective biocontrol agents for managing blue mold and other citrus postharvest diseases.

Exploration of Phage-Agrochemical Interaction Based on a Novel Potent Phage LPRS20-Targeting Ralstonia solanacearum.

Phage therapy has the potential to alleviate plant bacterial wilt. However, the knowledge gap concerning the phage-agrochemical interaction impedes the broader application of phages in agriculture. This study characterized a phage isolate and investigated its interactions with agrochemicals. A novel species within the Ampunavirus genus was proposed, serving phage LPRS20 as a type phage with a broad lytic range and significant antibacterial activity against Ralstonia solanacearum strains infecting tobacco, chili, or tomato. Sensory evaluation of the morphology of tobacco leaves suggested that phage application resulted in negligible harm to plants. Investigations into phage-agrochemical interactions revealed synergisms when LPRS20 was delivered 4 h before thiodiazole-copper as well as LPRS20 in combination with low-concentration berberine. Overall, our findings reveal that phage LPRS20 represents a novel, effective, and eco-friendly biocontrol agent against tobacco bacterial wilt in vivo and in vitro and contributes to the potential integration of phages and agrochemicals for controlling soil-borne pathogens.

Cyanophage-encoded auxiliary metabolic genes in modulating cyanobacterial metabolism and algal bloom dynamics

Cyanophages play a pivotal role in controlling cyanobacterial populations in aquatic environments. These dsDNA viruses harbor auxiliary metabolic genes (AMGs) that modulate the key metabolic processes of their cyanobacterial hosts, such as Photosynthesis, nutrient uptake for the optimization of viral replication. Recently, pan1~pan5 and pam1~pam5 cyanophages have been isolated from the fifth largest water resource in China; Lake Chaohu. Detailed genomic analysis of these phages revealed that these isolated cyanophages especially Pan1, Pam2 and Pam3 possess unique AMGs that significantly enhance the metabolic activities of their hosts, potentially leading to the suppression of bloom formation and stabilization of the ecological dynamics of Lake Chaohu. Our findings provide concrete evidence that cyanophages encoding AMGs could serve as effective biocontrol agents against harmful algal blooms, offering a targeted approach to manage these environmental threats. The integration of cyanophage-based management therapies with traditional methods could advance the efficiency and sustainability of controlling cyanobacterial outbreaks, paving the way for novel applications in water resource management. This review emphasizes the importance and critical need for further exploration of phage-host dynamics to fully harness the potential of cyanophages in ecosystem regulation.

Biocontrol efficacy of Botrytis cinerea on postharvest tomato fruit by the endophytic bacterium Bacillus velezensis BE1

Endophytic bacteria offer numerous advantages in the control of postharvest diseases. Bacillus velezensis has been identified as a promising biocontrol agent against postharvest pathogens in various fruits and vegetables. In this study, B. velezensis BE1 was identified by 16S rRNA sequencing and caused 76.9 % inhibition against Botrytis cinerea in dual culture assay. The cell-free culture filtrate (CFCF) of B. velezensis strongly inhibited the growth, spore germination, and germ tube elongation of B. cinerea. Moreover, 11 bioactive compounds were identified in the CFCF using gas chromatography-mass spectrometry, and phthalic acid, dioctyl ester was the predominant component by 72.92 %. Scanning and transmission electron microscopy observations revealed that the CFCF causes irreversible morphological and ultrastructural damage to the fungal hyphae and conidia, including deformed, wrinkled, lysis, collapse, and degradation of cytoplasmic organelles. The incidence and severity of gray mold were significantly suppressed after applying CFCF at 50 % in tomato fruit. The application of CFCF caused an increase in the total phenolics and flavonoids content in tomato fruit compared with the control throughout the experiment. Furthermore, the activities of enzymes associated with defense such as phenylalanine ammonia-lyase, polyphenoloxidase, and peroxidase were significantly higher in the treated tomatoes relative to the untreated group. These results indicate that B. velezensis BE1 has significant potential as an effective biocontrol agent against the pathogen B. cinerea, offering a valuable approach for controlling gray mold in postharvest fruit.

Molecular Identification and Antifungal Activity of Candida chrysomelidarum and Rhodotorula toruloides Isolated from Indonesian Indigenous Fruit Flacourtia inermis Roxb. (Lobi-lobi) against Pathogenic Mold Aspergillus flavus

Aspergillus flavus is one of the main contaminating mold species in most feed products, significantly impacting human and animal health. This study aims to isolate the epiphytic yeasts from the fruit Flacourtia inermis Roxb and test their potential ability to act as biocontrol agents for A. flavus. The antagonistic test was performed using a dual culture method, and the potential yeast isolates were then identified using a combination of morphology characterization and molecular sequence analysis. From 42 yeast isolated from F. inermis fruit, 2 yeast isolates (LCA 75 and LCA 102) demonstrated the highest inhibition growth against A. flavus (32.32 and 32.30 %, respectively). The isolates LCA 75 and LCA 102 were identified as Candida chrysomelidarum and Rhodotorula toruloides, respectively. Rhodotorula toruloides, identified as one of the yeast isolates (LCA 102), is an unconventional red yeast demonstrating notable antagonistic effects against A. flavus, inhibiting its growth by 32.30 %. This yeast, also known as Rhodosporidium toruloides, R. rubescens, R. glutinis, or R. gracilis, belongs to the subphylum Pucciniomycotina within the division Basidiomycota. The significant inhibition of mycelium growth and sporulation observed in our study highlights the potential of R. toruloides, along with C. chrysomelidarum (LCA 75), as effective biocontrol agents to reduce mycotoxin contamination in chicken feed by A. flavus. This study represents a significant advancement in the management of A. flavus contamination in animal feed. The findings not only underscore the viability of yeast-based biocontrol strategies but also contribute to a safer, more sustainable approach to preventing mycotoxin proliferation in feedstocks. HIGHLIGHTS Founding Out of 42 yeast isolates, two (LCA 75 and LCA 102) demonstrated the highest inhibition growth against A. flavus, with inhibition rates of 32.32 and 32.30 %, respectively. Identified Yeasts: LCA 75 as Candida chrysomelidarum LCA 102 as Rhodotorula toruloides (alternatively referred to as Rhodosporidium toruloides, R. rubescens, R. glutinis, or R. gracilis). Characteristics of Rhodotorula toruloides Unconventional red yeast belonging to the subphylum Pucciniomycotina within Basidiomycota. Commonly associated with various plant species and found on plant surfaces, including leaves, stems, and fruits. Identified yeast isolates exhibited inhibition activities leading to reduced mycelium growth and sporulation of A. flavus. These yeast isolates have potential as biocontrol agents to prevent mycotoxin contamination in chicken feed caused by A. flavus. GRAPHICAL ABSTRACT

Biocontrol Potential of Bacillus strains against soybean cyst nematode (Heterodera glycines) and for promotion of soybean growth

The soybean cyst nematode (SCN, Heterodera glycines) is the most yield-limiting pathogen in soybeans worldwide. Using chemical pesticides to control this disease is harmful to human and environment. It is urgent to develop environment-friendly nematicides. The aim of this study was to discover novel biocontrol agents on H. glycines control and soybean growth under greenhouse and field conditions Eight Bacillus strains were isolated from soil rhizosphere soils and the stability and efficiency of H. glycines was assessed in greenhouse and field experiments in 2021 and 2022. In particular, the Ba2-6 strain had the highest potential, because it was a biocontrol agent against H. glycines shown to cause 93.85% juvenile mortality. Furthermore, strains Ba 1–7, Ba2-4, and Ba2-6 effectively reduced the number of females and improved the soybean seed number per plant. Based on their morphological, physiological, biochemical and molecular (16 S rRNA) characteristics, the three strains were identified as B. aryabhattai (Ba1-7), B. megatherium (Ba2-4), and B. halotolerans (Ba2-6). The ability of Ba2-6 to induce systemic resistance to H. glycines in soybeans was investigated by the split-root system and real-time quantitative PCR experiments. The results indicated that the Ba2-6 strain induced systemic resistance to suppress the penetration of H. glycines, and enhanced gene expression of PR1, PR3a, PR5, and NPR1-2, involved in the salicylic acid and jasmonic acid pathways. The study suggests that the strains of B. aryabhattai Ba1-7, B. megatherium Ba2-4, and B. halotolerans Ba2-6 can be considered as effective biocontrol agents to control H. glycines. Further, B. halotolerans Ba2-6 not only promotes soybean growth but also enhances resistance to H. glycines by regulating defense-related gene expression and inducing systemic resistance in soybean.

Isolation and Characterization of Two Novel Lytic Bacteriophages against Salmonella typhimurium and Their Biocontrol Potential in Food Products.

Foodborne pathogens, such as Salmonella, are major factors that pose significant threats to global food safety and public health. Salmonella typhimurium is a prominent serotype contributing to non-typhoidal salmonellosis, which is a prevalent foodborne illness affecting humans and animals. Bacteriophages are considered one of the most environmentally friendly biocontrol agents, particularly in the food industry, owing to their high specificity and high safety. However, the emergency of phage-resistant mutants limits the biocontrol effect of phage treatment, leading to the requirement for a high diversity of lytic phages. Therefore, the study isolated and characterized two novel lytic Salmonella bacteriophages (SPYS_1 and SPYS_2) targeting S. typhimurium ATCC14028 and evaluated their effectiveness in reducing the contamination rates for milk and chicken tenders. Morphological and genomic analyses indicated that Salmonella phages SPYS_1 and SPYS_2 are novel species classified under the genus Skatevirus and the genus Berlinvirus, respectively. Both phages exhibited high stability across a broad range of thermal and pH conditions. The one-step growth curve result suggested that both phages had a short adsorption time and a large burst size in a single lytic cycle. The phage SPYS_1 demonstrated a noteworthy inhibition effect on the growth of S. typhimurium ATCC14028 in milk, resulting in a ~2-log reduction within the 2 to 4 h range. Overall, both phages have shown significant potential for application in food safety in the future.

Biological and genome characteristics of a novel broad host-range phage ΦEP1 infecting enteroinvasive Escherichia coli

We analyzed the biological and genome characteristics of a phage infecting enteroinvasive Escherichia coli (EIEC), aiming to provide resources and a reference for the prevention and treatment of EIEC. With the EIEC preserved in our laboratory as the host bacterium, one strain of phage was isolated from the effluent sample from a chicken farm in Huzhou, Zhejiang and named ΦEP1. The titer, optimal multiplicity of infection, one-step growth curve, temperature, pH value, chloroform and bile salt sensitivity of ΦEP1 were determined by the double-layer agar plate method. The morphology of the phage was observed by transmission electron microscopy. The biocontrol effects of ΦEP1 in different food matrixes and the protective effect of this phage on Caco-2 cells were tested. The phage ΦEP1 showed the optimal multiplicity of infection of 0.1, the titer of 1.3×1010 PFU/mL, strong tolerance to temperature, pH, chloroform, and bile salt, and a broad host spectrum. Furthermore, it expressed lysis activity against multiple strains of multiple antibiotic-resistant pathogenic E. coli and Shigella with different serotypes. Phage ΦEP1 had an incubation period of 10 min, an outbreak period of 80 min, and an outbreak volume of 48 PFU/cell. According to the morphology observed by transmission electron microscopy, phage ΦEP1 belonged to the order of Caudovirales, and it had a good protective effect on Caco-2 cells. Phage ΦEP1 had a genome of 87 182 bp with the GC content of 39.80%, 128 putative open reading frames, and no antibiotic resistance genes or virulence genes. ΦEP1 inhibited the growth of EIEC in artificially contaminated milk and beef and eliminated EIEC in cell protection experiments. It significantly increased the survival rate of Caco-2 cells and down-regulated the expression of interleukin (IL)-6 and IL-1β to reduce inflammation. We obtained an EIEC-targeting phage ΦEP1 with a high titer and strong tolerance to the environment, which provided a basis for the application of phages in food preservation and other fields.

Bacteriophages: Sustainable and effective solution for climate-resilient agriculture

Abstract Climate change entails significant challenges to global food security and agricultural sustainability, prompting the need for innovative solutions to enhance climate resilience in farming practices. Bacteriophages (phages), viruses that specifically target and infect bacteria, provide promising applications in numerous agricultural practices to address these challenges. With traits such as specificity towards bacterial pathogens along with self-replication, self-dosing, and adaptability properties phages offer potential as effective biocontrol agents while exerting minimal harm on non-target organisms or their surrounding environment. In this review, various applications of phages have been explored including increasing crop resilience, improving soil health, preserving food, managing water resources, and adapting to emerging pests and diseases. Additionally, the benefits of these applications are also explored, such as improving sustainable practices, enhancing plant growth and yield, and supporting pollinator health.Although they offer great promise, there are still several obstacles such as limited host range, environmental stability, and regulatory challenges, so further research and policies are required for their integration into agricultural systems. Furthermore, education and public awareness are essential for farmers to adopt phage-based biocontrol. By harnessing the potential of phages, agriculture can mitigate the adverse effects of climate change, promote sustainability, and ensure food security in a changing climate.