Inhibit Pathogen Growth Research Articles

Survey of Rice Sheath Blight Disease in Kuttanad and Effect of Biocontrol Agents and Fungicides against Rhizoctonia solani

Aims: Rice is an important crop cultivated worldwide, whose production is influenced by numerous factors like pest, disease, weather parameters. In India, diseases accounts for 35 per cent in yield reduction, with sheath blight being significant. This disease is notably prevalent in Kuttanad region of Kerala. This study involves a survey conducted in Kuttanad to assess the extent of the disease and in vitro management using biocontrol agents and fungicides. Study Design: Study was outlined in Completely Randomised Design (CRD) to evaluate the in vitro efficacy of bioagents. Place and Duration of Study: Department of Plant Pathology, College of Agriculture, Vellayani and M.S. Swaminathan Rice Research Station, Moncompu, between 2022 and 2023 Methodology: Survey was conducted in forty locations of Kuttanad in which the disease incidence was recorded and samples were collected. The isolates obtained were tested for pathogenicity by artificial inoculation on rice variety, Uma. Cultural characteristics of isolates were studied. The virulent culture obtained was further advanced for the in vitro studies with biocontrol agents and fungicides. The inhibition of fungal growth was also recorded. Results: Forty isolates of sheath blight pathogen (Rhizoctonia solani) were obtained. The virulent isolate among these was identified on the basis of number of days taken for symptom development by artificial inoculation and this was further advanced for the in vitro studies. Bacillus amyloliquefaciens was found to be more effective with an inhibition percentage of 68.64. Among the tested fungicides, Kresoxim methyl 40% + Hexaconazole 8% WG showed cent per cent growth inhibition of pathogen at 500 and 1000 ppm concentrations which was on par with Azoxystrobin 18.2% + Difenoconazole 11.4% SC at 1000 ppm. Conclusion: From this study, it can be concluded that, that these biocontrol agents and fungicides are very effective in the management of the pathogen and hence can be used for further field-level studies in management of the disease.

In vitro Efficacy of Different Fungicides against Leaf Blight of Sunflower

Sunflower is one of the major oilseed crops cultivated in India. Alternaria leaf blight is one of the fungal diseases of Sunflower caused due the pathogen Alternaria helianthi, which is one of the significant limitations in the cost-effective cultivation of Sunflower in India. It is estimated that 20 to 80% losses in yield and heavy defoliation have been observed due to A. helianthi causal agent of leaf blight of Sunflower. Present investigation on evaluation on efficacy of different fungicides against leaf blight of Sunflower under in vitro condition by using Completely Randomized Design was conducted at Department of Plant Pathology, Dr. Sharadchandra Pawar College of Agriculture, Baramati during. Under this study seven fungicides viz., Chlorothalonil 75% WP, Hexaconazole 5% EC, Carbendazim+Mancozeb 75% WP, Carbendazim 50% WP, Tebuconazole 25.9% EC, Propiconazole 25% EC and Azoxystrobin 23% SC were evaluated against the pathogen Alternaria helianthi causing leaf blight in Sunflower at their recommended concentration and observation on mean radial mycelial growth and percent mycelial growth inhibition of pathogen was calculated. Results revealed that among various fungicides the three fungicides viz., Hexaconazole 5% EC, Tebuconazole 25.9% EC and Propiconazole 25% EC were found most effective with minimum mean mycelial growth and having maximum and similar (94.44%) percent growth inhibition of pathogen and rest of the fungicides tested were comparatively less effective against the pathogen A. helainthi associated with leaf blight of Sunflower.

Dietary Probiotic Pediococcus acidilactici GKA4, Dead Probiotic GKA4, and Postbiotic GKA4 Improves Cisplatin-Induced AKI by Autophagy and Endoplasmic Reticulum Stress and Organic Ion Transporters.

Acute kidney injury (AKI) syndrome is distinguished by a quick decline in renal excretory capacity and usually diagnosed by the presence of elevated nitrogen metabolism end products and/or diminished urine output. AKI frequently occurs in hospital patients, and there are no existing specific treatments available to diminish its occurrence or expedite recovery. For an extended period in the food industry, Pediococcus acidilactici has been distinguished by its robust bacteriocin production, effectively inhibiting pathogen growth during fermentation and storage. In this study, the aim is to assess the effectiveness of P. acidilactici GKA4, dead probiotic GKA4, and postbiotic GKA4 against cisplatin-induced AKI in an animal model. The experimental protocol involves a ten-day oral administration of GKA4, dead probiotic GKA4, and postbiotic GKA4 to mice, with a cisplatin intraperitoneal injection being given on the seventh day to induce AKI. The findings indicated the significant alleviation of the renal histopathological changes and serum biomarkers of GKA4, dead probiotic GKA4, and postbiotic GKA4 in cisplatin-induced nephrotoxicity. GKA4, dead probiotic GKA4, and postbiotic GKA4 elevated the expression levels of HO-1 and decreased the expression levels of Nrf-2 proteins. In addition, the administration of GKA4, dead probiotic GKA4, and postbiotic GKA4 significantly reduced the expression of apoptosis-related proteins (Bax, Bcl-2, and caspase 3), autophagy-related proteins (LC3B, p62, and Beclin1), and endoplasmic reticulum (ER) stress-related proteins (GRP78, PERK, ATF-6, IRE1, CHOP, and Caspase 12) in kidney tissues. Notably, GKA4, dead probiotic GKA4, and postbiotic GKA4 also upregulated the levels of proteins related to organic anion transporters and organic cation transporters. Overall, the potential therapeutic benefits of GKA4, dead probiotic GKA4, and postbiotic GKA4 are significant, particularly after cisplatin treatment. This is achieved by modulating apoptosis, autophagy, ER stress, and transporter proteins to alleviate oxidative stress.

Comparative In vitro Assessment of Fungicides for Managing Fusarium oxysporum f. sp. capsici in Chilli

Chilli wilt disease, caused by Fusarium oxysporum f. sp. capsici, significantly threatens chili cultivation, impacting yield and quality. This study aimed to evaluate the fungi-toxic effects of various fungicides against Fusarium oxysporum f. sp. capsici under in vitro conditions. Eight different fungicides viz., Tebuconazole 6.7 % + Captan 26.9 % w/w SC, Thiophenate Methyl 70% WP, Carbendazim 12% + Mancozeb 63% WP, Tebuconazole 50% + Trifloxystrobin 25% WG, Carbendazim 50% WP, Pyraclostrobin 20% WG, Chlorothalonil 75% WP and Azoxystrobin 18.2%+ Difenoconazole 11.4% SC were tested at a concentration of 500 ppm and 1000 ppm using the Poison food technique. The experiment was designed using a Completely Randomized Design (CRD) and conducted at the Department of Plant Pathology, Dr. Sharadchandra Pawar College of Agriculture, Baramati, during the academic year 2023-24. All fungicides significantly (P < 0.01) inhibited the mycelial growth of Fusarium oxysporum f.sp. capsici, with Carbendazim 12% + Mancozeb 63% WP showing the highest efficacy, followed by Tebuconazole 50% + Trifloxystrobin 25% WG and Tebuconazole 6.7 % + Captan 26.9 % w/w SC across both concentrations. This study suggests that the inhibition of pathogen growth increased with higher fungicide concentrations.

Interpenetrated Polymer Network Systems (PEG/PNIPAAm) Using Gamma Irradiation: Biological Evaluation for Potential Biomedical Applications

The potential antimicrobial and antibiofouling properties of previously synthesized PEG/NiPAAm interpenetrated polymer networks (IPNs) were investigated against three of the most common bacteria (E. coli, S. aureus, and S. epidermidis). The main goal was to evaluate the material’s biocompatibility and determine its potential use as an antifouling component in medical devices. This was intended to provide an alternative option that avoids drug usage as the primary treatment, thus contributing to the fight against antimicrobial resistance (AMR). Additionally, characterization and mechanical testing of the IPN were carried out to determine its resistance to manipulation processes in medical/surgical procedures. IPNs with different NiPAAm ratios exhibited excellent cytocompatibility with BALB/3T3 murine fibroblast cells, with cell viability values of between 90 and 98%. In addition, the results regarding the adsorption of albumin as a model protein showed a nearly constant adsorption percentage of almost zero. Furthermore, the bacterial inhibition tests yielded promising results, demonstrating effective pathogen growth inhibition after 48 h. These findings suggest the material’s suitability for use in biomedical applications.

Leucoanthocyanidin Reductase 3 (PaLAR3) Locus in Norway Spruce (Picea abies) and Its Link to Resistance Against Heterobasidion parviporum

ABSTRACTHeterobasidion parviporum is a fungal pathogen that is drastically damaging Norway spruce (Picea abies) in Europe. The infections will result in root and stem rot, causing significant economic losses for forest owners. Previous studies have shown that the PaLAR3 gene, which encodes the leucoanthocyanidin reductase enzyme, can increase resistance to H. parviporum in Norway spruce. The presence of the B allele at the PaLAR3 locus has been associated with higher (+)‐catechin concentrations and increased enzyme production in inoculation experiments, resulting in inhibited pathogen growth. The control of H. parviporum involves a multifaceted approach, including silvicultural and sustainable forestry practices, genetic resistance and chemical/biological control. In this study, we determined the PaLAR3 genotypes in a representative sample of Norway spruce breeding materials from southern Finland and examined their effect on necrosis caused by H. parviporum in spruce stems. The results showed that the homozygous PaLAR3BB genotype was present in only 9% of the trees. However, the necrotic area interacted with homozygous PaLAR3BB under low‐water treatment. These findings support the idea that the PaLAR3 locus may be a valuable marker for identifying P. abies resistance to different strains of Heterobasidion parviporum.

Green Silver Nanoparticles and Their Activity as Antifungal Agents Against Penicillium digitatum Causing Green Mould of Citrus

AbstractThe green synthesis of silver nanoparticles (SNPs) using aqueous extracts of five plants viz., Ocimum americanum, Azadirachta indica, Allium sativum, Eucalyptus hybrida, Zingiber officinale were evaluated for their antifungal property against Penicillium digitatum, a green mould pathogen of citrus fruits. The five plant species were selected from a screening of aqueous extracts from 16 plant species. The efficacy of aqueous extracts, at 50 % concentration, ranged from 14.44–68.52 % inhibition in mycelia growth of P. digitatum. Among SNPs, O. americanum was found most efficacious, at 1000 ppm concentration, with 80.7 % mycelial inhibition followed by A. indica with 77.4 % mycelial growth inhibition of fungal pathogen. Further, physical and structural characterization of SNPs of O. americanum and A. indica was carried out. The characterization analysis executed via transmission and scanning electron microscope revealed size distribution and nanoparticles were spherical to irregularly shaped ranging from 22.8–250 nm in O. americanum and 26.5–500 nm in A. indica. In UV‐visible spectrophotometer, the absolute absorption peak was recorded at 448 nm and 442 nm for O. americanum and A. indica, respectively. FTIR analysis of SNPs of A. indica and O. americanum confirmed the presence of carboxyl, amide group and secondary amines which were the main constituent of proteins. The novelty of the present study is in the green synthesis of silver nanoparticles with potential in the management of postharvest pathogens of fruit crops. The synthesis of SNPs used in this study is simple, environmentally benign and cost‐effective using aqueous extract of native plants.

Sustainable gelatin-kappa carrageenan active packaging with Mekwiya date seeds to enhance goat meat quality and shelf life

This research aimed to elaborate a gelatin-Kappa carrageenan-based packaging with 0.22 %, 0.44 %, and 0.88 % w/v of Mekwiya date palm seeds extract (DSEMK). This extract improved the mechanical, physical, and thermal properties of the films. Moisture content, water solubility, and water vapor permeability were reduced from 17.54 ± 0.02 to 12.18 ± 0.02, from 77.61 ± 0.02 to 25.35 ± 0.29 %, and from 5.28 ± 0.29 to 1.69 ± 0.03 g s−1 m−1 Pa−1 × 10−10, respectively. During thermal degradation, DSEMK4 film had a residual weight of 27.99 %, compared to 20.67 % for the control. Despite a decline in the film's tensile strength from 24.19 to 8.94 MPa with the incorporation of DSEMK, elongation at the breaking point increased from 37.66 ± 0.16 to 46.17 ± 0.25 %. The film containing DSEMK4 displayed the highest phenolic contents and illustrated the best antioxidant effects in DPPH and FRAP assays, with IC50s of 756 and 1445 μg/mL, respectively and inhibited pathogen growth on the meat surface. Over storage at 4 °C, monitoring of pH, lipid and protein oxidation parameters, microbial spoilage, optical properties, and sensory attributes disclosed that the DSEMK-films successfully enhanced the meat quality and safety. These findings were supported by principal component analysis and heat maps.

The Effects of Bioinoculants on Enhancement Growth in Nanjanagud Rasabale Tissue Culture Banana

Bio-hardening is a process where micro propagated plantlets are inoculated with suitable strains of microorganisms in order to enhance their acclimatization. Trials were taken to expose banana plantlets to useful microbes that encourage growth and mutual association during 2022 at UHS, Bagalkot. It promotes host plant growth, plant nutrient uptake, inhibits pathogen growth, reduces disease severity, enhances tolerance to environmental stress etc. In the present study, twenty treatments were imposed with different bioinoculants by two methods of application (1) powder formulation and (2) liquid formulation. Among these treatments, M1T13- VAM and fusicont significantly increased the survivability per cent (58.80%), plant height (6.46 cm), pseudo stem girth (5.42 cm), number of leaves (4.07) and leaf area (33.15 cm2). Thus, the artificial inoculation of bioinoculants through the powder formulation enhances the growth during primary hardening.

Bacillus species are core microbiota of resistant maize cultivars that induce host metabolic defense against corn stalk rot

BackgroundMicrobes colonizing each compartment of terrestrial plants are indispensable for maintaining crop health. Although corn stalk rot (CSR) is a severe disease affecting maize (Zea mays) worldwide, the mechanisms underlying host–microbe interactions across vertical compartments in maize plants, which exhibit heterogeneous CSR-resistance, remain largely uncharacterized.ResultsHere, we investigated the microbial communities associated with CSR-resistant and CSR-susceptible maize cultivars using multi-omics analysis coupled with experimental verification. Maize cultivars resistant to CSR reshaped the microbiota and recruited Bacillus species with three phenotypes against Fusarium graminearum including niche pre-emption, potential secretion of antimicrobial compounds, and no inhibition to alleviate pathogen stress. By inducing the expression of Tyrosine decarboxylase 1 (TYDC1), encoding an enzyme that catalyzes the production of tyramine and dopamine, Bacillus isolates that do not directly suppress pathogen infection induced the synthesis of berberine, an isoquinoline alkaloid that inhibits pathogen growth. These beneficial bacteria were recruited from the rhizosphere and transferred to the stems but not grains of the CSR-resistant plants.ConclusionsThe current study offers insight into how maize plants respond to and interact with their microbiome and lays the foundation for preventing and treating soil-borne pathogens.FCn65Jq_7Sh4F-UA4uQM99Video

Identification of Biomarkers Associated with Phyllosticta citricarpa Tolerance.

Citrus black spot (CBS) is a fungal disease caused by Phyllosticta citricarpa Kiely, (McAlpine Van der Aa), with most cultivars being susceptible to infection. Currently, disease control is based on the application of protective fungicides, which is restricted due to resistance, health and environmental concerns. Although using natural products for disease management is gaining momentum, more advances are required. This study obtained the metabolic profiles of the essential oil and cuticular waxes of two citrus cultivars with a varying susceptibility to CBS infection using gas chromatography-mass spectrometry. A multivariate data analysis identified possible biomarker compounds that contributed to the difference in susceptibility between the two cultivars. Several identified biomarkers were tested in vitro for their antifungal properties against P. citricarpa. Two biomarkers, propanoic acid and linalool, were able to completely inhibit pathogen growth at 750 mg/L and 2000 mg/L, respectively.

The effect and mechanism of Debaryomyces nepalensis and six strains of winter jujube epiphytic bacteria in building a synthetic community to control post-harvest black spot disease of winter jujube

The study aimed to develop a synthetic microbial community capable of managing postharvest black spot disease in winter jujube. The research revealed that treatment with Debaryomyces nepalensis altered the surface microbial community, reducing the presence of harmful fungi such as Alternaria, Penicillium, Fusarium, and Botrytis, while boosting beneficial bacteria like Pantoea, Bacillus, Staphylococcus, and Pseudomonas, leading to a decreased decay rate in date fruits. A synthetic community was crafted, integrating D. nepalensis with seven other bacterial strains selected for their abundance, compatibility, culturability, and interactions. This community was refined through homo-pore damage experiments and safety assessments to a final formulation consisting of D. nepalensis and six other bacteria: Bacillus subtilis, Bacillus velezensis, Staphylococcus arlettae, Staphylococcus gallinarum, Pseudomonas sp., and Pseudomonas psychrotolerans. Fruit inoculation tests demonstrated that this synthetic community (6 + 1) significantly lowered the incidence and size of black spot lesions compared to single-strain treatments. By the 10th day of storage, the incidence was 69.23 % lower than the control and 52.94 % lower than the group treated solely with D. nepalensis. Mechanistic studies of the synthetic community's antibacterial effects showed that it can produce volatile compounds, proteases, and β-1,3-glucanase to inhibit pathogen growth. Additionally, the community forms a biofilm to compete for nutrients and induce jujube resistance to disease.

Exploring the biocontrol and plant growth-promoting potential of Streptomyces kronopolitis isolate SA18 against durian foliar blight and dieback disease

Abstract. Kraivuttinun P, Pirapak K, Pinnak P, Pirapak W. 2024. Exploring the biocontrol and plant growth-promoting potential of Streptomyces kronopolitis isolate SA18 against durian foliar blight and dieback disease. Biodiversitas 25: 2661-2669. Actinomycetes have been extensively studied for their potential as plant growth promoters and biocontrol agents against fungal plant pathogens. In Thailand, durian is a highly valuable fruit crop, celebrated for its delectable fleshy arils. Rhizoctonia solani destruction causes foliar blight and dieback, a severe disease on durian plantations. Our investigation objective was to isolate, select, and identify actinomycetes that exhibit antagonistic properties and could improve the growth of durian. This study revealed that 37 actinomycete isolates were obtained, comprising 14 endophytic isolates and 23 soil-derived actinomycete isolates from durian plantations in Thailand's Uttaradit and Sukhothai Provinces. All actinomycete isolates demonstrated the ability to inhibit pathogen growth through in vitro antagonistic bioassay. Isolate SA18 exhibited the highest percentage inhibition of radial growth against R. solani isolate 01, achieving an impressive 92% inhibition. Furthermore, isolate SA18 demonstrated the capacity to produce 5.91 ?g/mL of indole acetic acid after seven days of culture, increasing to 45.72 ?g/mL after 14 days. This isolate also exhibited phosphate solubilization ability. In the detached leaf bioassay, isolate SA18 effectively controlled the spread of fungal pathogens, reducing disease severity significantly from 93.75% in the control treatment to 53.75% with a concentration of 108 spores/mL of isolate SA18. Morphological examination and 16S rRNA gene sequencing revealed that isolate SA18 formed smooth-surfaced spores in chains and showed a close relationship with Streptomyces kronopolitis based on the 16S rDNA sequence. This study is the first to report the presence of S. kronopolitis in soil samples collected from durian orchards in Thailand. This isolate can improve plant growth and control R. solani in bioassays. S. kronopolitis isolate SA18 can potentially be a biocontrol agent for durian plantations.

Exploring Endophytic Bacteria from Artemisia spp. and Beneficial Traits on Pea Plants.

Endophytic microorganisms represent promising solutions to environmental challenges inherent in conventional agricultural practices. This study concentrates on the identification of endophytic bacteria isolated from the root, stem, and leaf tissues of four Artemisia plant species. Sixty-one strains were isolated and sequenced by 16S rDNA. Sequencing revealed diverse genera among the isolated bacteria from different Artemisia species, including Bacillus, Pseudomonas, Enterobacter, and Lysinibacillus. AR11 and VR24 obtained from the roots of A. absinthium and A. vulgaris demonstrated significant inhibition on Fusarium c.f. oxysporum mycelial growth. In addition, AR11, AR32, and CR25 exhibited significant activity in phosphatase solubilization, nitrogen fixation, and indole production, highlighting their potential to facilitate plant growth. A comparative analysis of Artemisia species showed that root isolates from A. absinthium, A. campestris, and A. vulgaris have beneficial properties for inhibiting pathogen growth and enhancing plant growth. AR11 with 100% similarity to Bacillus thuringiensis, could be considered a promising candidate for further investigation as microbial biofertilizers. This finding highlights their potential as environmentally friendly alternatives to chemical pesticides, thereby contributing to sustainable crop protection practices.

Antifeedant, antifungal and nematicidal compounds from the endophyte Stemphylium solani isolated from wormwood

The continuous search for natural product-based biopesticides from fungi isolated from untapped sources is an effective tool. In this study, we studied a pre-selected fungal endophyte, isolate Aa22, from the medicinal plant Artemisia absinthium, along with the antifungal, insect antifeedant and nematicidal compounds present in the extract. The endophyte Aa22 was identified as Stemphylium solani by molecular analysis. The antifungal activity was tested by broth microdilution against Fusarium solani, F. oxysporum, F. moniliforme and Botrytis cinerea, the insect antifeedant by choice bioassays against Spodoptera littoralis, Myzus persicae and Rhopalosiphum padi and the in vitro mortality against the root-knot nematode Meloiydogyne javanica. The structures of bioactive compounds were determined on the basis of 1D and 2D NMR spectroscopy and mass spectrometry. The ethyl acetate extract obtained from the solid rice fermentation showed mycelial growth inhibition of fungal pathogens (EC50 0.08–0.31 mg/mL), was antifeedant to M. persicae (99%) and nematicidal (68% mortality). A bioguided fractionation led to the isolation of the new compound stempholone A (1), and the known stempholone B (2) and stemphol (3). These compounds exhibited antifeedant (EC50 0.50 mg/mL), antifungal (EC50 0.02–0.43 mg/L) and nematicidal (MLD 0.5 mg/mL) activities. The extract activities can be explained by 3 (antifungal), 1–3 (antifeedant) and 1 (nematicidal). Phytotoxicity tests on Lolium perenne and Lactuca sativa showed that the extract and 1 increased L. sativa root growth (121–130%) and 1 reduced L. perenne growth (48–49%). These results highlight the potential of the endophytic fungi Aa22 as biotechnological source of natural product-based biopesticides.

Amylolytic Capability and Performance of Probiotic Strains in a Controlled Sorghum Fermentation System

This study aimed to explore the fermentative performance of nine lactic acid bacterial strains with probiotic potential during sorghum fermentation. The strain’s attributes including proliferation counts, pH levels, production of organic acid antibacterial activity, and their ability to break down starch were evaluated during the fermentation period in the presence and absence of glucose as a carbon source. In addition, the inhibitory activity of these potential probiotic strains against pathogenic bacteria (Salmonella typhimurium, Escherichia coli, and Staphylococcus aureus) was examined through a co-culturing technique. The results demonstrated that all 4 Lactobacillus strains exhibited robust growth in both glucose and glucose-free fermentation experiments. Glucose supplementation significantly enhanced lactic acid yield which ranged from 0.19 to 0.44% compared to fermentation without glucose which ranged from 0.04 to 0.29%. The selected Lactobacillus strains effectively lowered the media pH below 4.0 after 24 h, producing substantial lactic acid. Notably, in the absence of glucose, only Lb. helveticus D7 and Lb. amylolyticus D12 achieved pH levels below 4 after 8 h, producing the highest lactic acid amounts of 0.27 and 0.29% after 24 h, respectively. Amylase activity was detected on two strains, D7 and D12. Furthermore, most of the tested Lactobacillus strains demonstrated complete inhibition (6 log to 0 Log CFU/mL) of pathogen growth after 24 h of co-culturing, suggesting their potential for enhancing the safety quality of sorghum-based fermented products.

Diallyl Trisulfide Acts as a Soil Disinfestation Against the Ilyonectria destructans through Inducing the Burst of Reactive Oxygen Species.

Soil-borne diseases represent an impediment to the sustainable development of agriculture. A soil-borne disease caused by Ilyonectria destructans severely impacts Panax species, and soil disinfestation has proven to be an effective management approach. Here, diallyl trisulfide (DATS), derived from garlic, exhibited pronounced inhibitory effects on the growth of I. destructans in vitro tests and contributed to the alleviation of soil-borne diseases in the field. A comprehensive analysis demonstrated that DATS inhibits the growth of I. destructans by activating detoxifying enzymes, such as GSTs, disrupting the equilibrium of redox reactions. A series of antioxidant amino acids were suppressed by DATS. Particularly noteworthy is the substantial depletion of glutathione by DATS, resulting in the accumulation of ROS, ultimately culminating in the inhibition of I. destructans growth. Briefly, DATS could effectively suppress soil-borne diseases by inhibiting pathogen growth through the activation of ROS, and it holds promise as a potential environmentally friendly soil disinfestation.

Rhizospheric microbiota of suppressive soil protect plants against Fusarium solani infection.

Fusarium infection has caused huge economic losses in many crops. The study aimed to compare the microbial community of suppressive and conducive soils and relate to the reduction of Fusarium wilt. High-throughput sequencing and microbial network analysis were used to investigate the differences in the rhizosphere microbiota of the suppressive and conducive soils and to identify the beneficial keystone taxa. Plant pathogens were enriched in the conducive soil. Potential plant-beneficial microorganisms and antagonistic microorganisms were enriched in the suppressive soil. More positive interactions and keystone taxa existed in the suppressive soil network. Thirty-nine and 16 keystone taxa were identified in the suppressive and conducive soil networks, respectively. Sixteen fungal strains and 168 bacterial strains were isolated from suppressive soil, some of which exhibited plant growth-promotion traits. Thirty-nine bacterial strains and 10 fungal strains showed antagonistic activity against F. solani. Keystone taxa Bacillus and Trichoderma exhibited high antifungal activity. Lipopeptides produced by Bacillus sp. RB150 and chitinase from Trichoderma spp. inhibited the growth of F. solani. Microbial consortium I (Bacillus sp. RB150, Pseudomonas sp. RB70 and Trichoderma asperellum RF10) and II (Bacillus sp. RB196, Bacillus sp. RB150 and T. asperellum RF10) effectively controlled root rot disease, the spore number of F. solani was reduced by 94.2% and 83.3%. Rhizospheric microbiota of suppressive soil protects plants against F. solani infection. Antagonistic microorganisms in suppressive soil inhibit pathogen growth and infection. Microbial consortia consisted of keystone taxa well control root rot disease. These findings help control Fusarium wilt. © 2024 Society of Chemical Industry.

Evalution of co-culture system on Debaryomyces hansenii and Bacillus atrophaeus strains and its efficacy on disease control and quality maintenance of postharvest fruit

Microbial antagonists are used to manage both pre- and postharvest diseases of fruit crops. Mixing two types of antagonists has been reported to enhance the viability, stability, and biocontrol efficacy of each strain used individually. In the present study, a co-cultivation system for Debaryomyces hansenii (Y-1) and Bacillus atrophaeus (TE-7) strains was evaluated, and the regulatory mechanism associated with antagonistic activity and postharvest disease control in mango and litchi fruits was investigated. Results indicated that the optimized co-cultivation system for Y-1 and TE-7 (Y + T) significantly promoted the growth of both strains, compared to single cultures, and improved their ability to adapt to co-cultivation conditions. Non-targeted metabolomics revealed that characteristic metabolites, including N-Acetyl-L-glutamic acid, adenine, umbelliferone, and cucurbitacin B significantly accumulated in co-culture, which involved in citrate cycle (TCA cycle), amino acid biosynthesis, phenylpropanoid biosynthesis, and alkaloid biosynthesis. Subsequent in vivo and in vitro assays indicated that the Y + T system, relative to the use of the individual strains, significantly enhanced the inhibition of pathogen growth, increased disease control, and also decreased weight loss and changes in peel color. The co-culture also enhanced the content of total acids (TA) and total soluble solids (TSS) in mango and litchi fruits compared to the control group. These results suggest that the Y + T co-cultivation system is highly effective in antagonistic protection, disease control, and quality maintenance of postharvest fruit. Our study provides new insights into the interactions that occur between biocontrol microorganisms in a co-culture system, and information that can be used for the development of improved strategies for the postharvest preservation of fruit.

Plant growth-promoting bacteria potentiate antifungal and plant-beneficial responses of Trichoderma atroviride by upregulating its effector functions.

Trichoderma uses different molecules to establish communication during its interactions with other organisms, such as effector proteins. Effectors modulate plant physiology to colonize plant roots or improve Trichoderma's mycoparasitic capacity. In the soil, these fungi can establish relationships with plant growth-promoting bacteria (PGPBs), thus affecting their overall benefits on the plant or its fungal prey, and possibly, the role of effector proteins. The aim of this study was to determine the induction of Trichoderma atroviride gene expression coding for effector proteins during the interaction with different PGPBs, Arabidopsis or the phytopathogen Fusarium brachygibbosum, and to determine whether PGPBs potentiates the beneficial effects of T. atroviride. During the interaction with F. brachygibbosum and PGPBs, the effector coding genes epl1, tatrx2 and tacfem1 increased their expression, especially during the consortia with the bacteria. During the interaction of T. atroviride with the plant and PGPBs, the expression of epl1 and tatrx2 increased, mainly with the consortium formed with Pseudomonas fluorescens UM270, Bacillus velezensis AF12, or B. halotolerans AF23. Additionally, the consortium formed by T. atroviride and R. badensis SER3 stimulated A. thaliana PR1:GUS and LOX2:GUS for SA- and JA-mediated defence responses. Finally, the consortium of T. atroviride with SER3 was better at inhibiting pathogen growth, but the consortium of T. atroviride with UM270 was better at promoting Arabidopsis growth. These results showed that the biocontrol capacity and plant growth-promoting traits of Trichoderma spp. can be potentiated by PGPBs by stimulating its effector functions.