Biocontrol Research Articles

An eco-epidemiological model for malaria with Microsporidia MB as bio-control agent

Microsporidia MB is an endosymbiont which naturally infects Anopheles mosquitoes. Due to its ability to block Plasmodium transmission, it shows potential as a bio-based agent for the control of malaria. Its self-sustainability is promising, as it can spread through both vertical and horizontal transmissions. However, its low prevalence in mosquito populations remains a challenge. We develop an eco-epidemiological mathematical model describing the co-dynamics of Microsporidia MB (within mosquito population) and malaria (within human population). The model is used to assess the potential of Microsporidia MB-infected mosquitoes on the control of malaria infection. The results on the basic reproduction numbers, the stability of the equilibria, and the existence of bifurcations are obtained, providing conditions for the extinction and persistence of MB-infected mosquitoes. We highlight relevant threshold parameters for the elimination and persistence of MB-infected mosquitoes and malaria-infected individuals. Using real data from Kenya, we found that, given a horizontal transmission rate between 0 and 0.5, a minimum vertical rate of 0.55 is required to avoid extinction of MB-infected mosquitoes. The predicted prevalence of MB-infected mosquitoes using transmission rates reported from lab experiments align with the observed low prevalence of MB-infected mosquitoes in the field, thereby validating our model and results. Finally, predictions indicate that increasing MB mosquito infection could effectively control malaria, with target prevalence varying by region: 15% in Highland, 40% on the coast, and 70% in the Lake region. This study offers insights into the use of bio-based vector population replacement solutions to reduce malaria incidence in regions where Microsporidia MB is prevalent.

The biocontrol paradox.

The biocontrol paradox.

Nonanol, an Induced Biomolecule Produced by Bacillus atrophaeus NMB01 During Interaction With Phytophthora infestans Can be Explored as a Novel Formulation for the Management of Late Blight of Potatoes.

Phytophthora infestans, the pathogen responsible for late blight, continues to pose a significant risk to worldwide potato cultivation, including its historical impact during the Irish Potato Famine. Traditional management relies heavily on synthetic fungicides, but their prolonged use has led to fungicide resistance and environmental concerns. This study examines the potential of the bacterial endophyte Bacillus atrophaeus NMB01 as a biocontrol agent against P. infestans. Six biomolecules produced by B. atrophaeus NMB01 were docked against 15 P. infestans protein targets, with 1-nonanol, glafenine hydrochloride, and mucic acid showing high binding affinity. Wet lab assays confirmed that 1-nonanol inhibited P. infestans mycelial growth by 78% at 2 ppm. Molecular dynamics simulations validated the stability of these interactions. A tri-trophic interaction study identified additional volatile and non-volatile organic compounds (VOCs/NVOCs), with minocycline and doxazosin exhibiting strong binding across all targets. Transcriptome analysis of P. infestans exposed to 1-nonanol revealed differential gene expression, with upregulated genes linked to stress responses and downregulated genes, such as TAR1, cysteine synthase, and glutathione transferase, presenting novel antifungal targets. This study highlights 1-nonanol as a promising eco-friendly alternative to conventional fungicides, offering a sustainable solution for managing late blight and advancing potato cultivation resilience.

Study of the Biological Characteristics of Bacillus amyloliquefaciens subsp. plantarum 71 in NOVO TECH 888 and Its Effect on Fusarium Wilt in Strawberry Plants in vitro

The biological characteristics of Bacillus amyloliquefaciens subsp. plantarum 71, obtained from the commercial product NOVO TECH 888 (Atomes F.D. Inc., Canada), were studied. Morphological and biochemical identification revealed that the bacterium is rod-shaped, Gram-positive, motile, catalase-positive, urease-producing, spore-forming, and facultatively aerobic. It is capable of degrading starch, gelatin, and pectin, and is tolerant to salt concentrations ranging from 2-10% NaCl. The bacterium proliferates actively within a temperature range of 25 to 50 °C, with an optimal growth temperature of 35 °C, indicating its thermophilic nature. It can grow across a broad pH range (pH 4, 7, and 10), demonstrating its adaptability to diverse environmental conditions. The bacterial cell concentration in 1 mL of the commercial product was determined to be 5.32 × 109 CFU. The bacterium retained its viability in the commercial product for three years without any significant decrease in its activity. Additionally, it was confirmed that the bacterium was unaffected by copper in the form of copper sulfate pentahydrate (Cu2SO4·5H2O) or copper hydroxide Cu (OH)2, nor by sulfur under controlled laboratory conditions. The efficacy of this bacterium in controlling the vascular wilt fungus Fusarium oxysporum f. sp. fragariae, isolated from strawberry plants, was also evaluated. The bacterium inhibited fungal mycelial growth on nutrient agar plates and induced morphological deformities in the fungal mycelium. These results indicate the promising potential of B. amyloliquefaciens as a biocontrol agent for Fusarium wilt disease in strawberries, making it a viable option for use in organic agriculture.

Blue-green partnership: unravelling potential of marine Pseudomonas aeruginosa OG as a biocontrol agent against Fusarium oxysporum vasinfectum

Cotton, a crop of significant economic importance in India, is confronted with a multitude of soil-borne illnesses. Fusarium wilt, caused by the pathogen Fusarium oxysporum f. sp. vasinfectum (FOV). This disease may have a significant negative impact on production levels. Various management techniques including the physical and chemical methods are developed but has limitations like effect on non-target organism, development of resistance by organism, accumulation in the soil and negative impact on Environment etc. Looking to above constrains, more effective ecofriendly techniques for disease management should be developed which may include use of microbes. The objective of this research was to determine the efficacy of marine Pseudomonas aeruginosa OG101 as a biocontrol agent. The organism showed presence of genes of lytic enzymes like glucanase and chitinase as well as several antibiotic genes whose synthesis may be effective in reducing FOV infection in plants. OG101 was found as an effective biocontrol agent both in in vitro and in vivo. Even in in vivo conditions, it was able to improve height and weight of cotton plant by 52.11% and 63.30% respectively. Based on the results of the study, it was shown that OG101 exhibited bio-control capabilities by exerting inhibitory effects on FOV, hence providing protection against disease in cotton. This study clearly demonstrates usefulness of marine microbe in controlling the Fusarium infection in cotton plant.

Eco-friendly management of Fusarium wilt in tomato using Salvia officinalis methanolic extract: in vitro, in vivo, and molecular docking approaches

Abstract Fusarium wilt, caused by Fusarium oxysporum f. sp. lycopersici, threatens global tomato production, with losses reaching 80%. Although chemical fungicides are effective, their prolonged use risks resistant strains, reduces soil biodiversity, and causes environmental damage, highlighting the urgent need for ecofriendly alternatives. This study investigated the viability of Salvia officinalis (sage) methanolic extract as a biocontrol agent against Fusarium wilt (FW), employing a comprehensive approach that incorporates in vitro, in vivo, and molecular docking techniques. Four distinct isolates of F. oxysporum were identified through molecular techniques, and their virulence was assessed by examining the presence of tomatinase genes. The antifungal properties of S. officinalis extract were found to be compelling, with a total phenolic content of 64.15 mg GAE/g and a remarkable antioxidant activity of 97.04%. In laboratory tests, S. officinalis exhibited potent antifungal activity, inhibiting mycelial growth by between 52.00% and 88.67% at a concentration of 20 mg/ml. Additionally, in vivo experiments demonstrated a significant reduction in disease severity in treated tomato plants. Molecular docking analyses revealed strong binding affinities between key phytochemicals in the extract and target receptors such as tomatinase, highlighting the potential of the extract as a sustainable and effective alternative to chemical fungicides for managing FW in tomato crops.

A combination of predator and selective pesticide improves control of resistant Aphis gossypii (Hemiptera: Aphididae).

The cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), is a major pest in cotton production, notorious for its rapid development of resistance to pesticides, which complicates control efforts. A sustainable solution involves combining selective insecticides with biocontrol agents to reduce pest populations while preserving natural enemies. Afidopyropen, a novel transient receptor potential vanilloid-targeted insecticide, was extremely safe for the minute pirate bug Orius sauteri Poppius (Hemiptera: Anthocoridae), a common predator of small pests. The LC50 values for direct exposure were 592.38, 497.02, and 382.71 mg/L for the fifth instars and female and male adults, respectively. Even at the maximum recommended field rate, afidopyropen had minimal impact on the survival, predation efficiency, and reproduction of pesticide-treated O. sauteri and their offspring. Despite the resistance observed in field-collected A. gossypii, combining a low concentration of afidopyropen with O. sauteri significantly reduced aphid populations. By day 7 post-treatment, aphid density was decreased by over 94.29%. While a higher concentration of afidopyropen initially achieved 98.19% control, aphid populations rebounded over time. This study demonstrated that afidopyropen was extremely safe for O. sauteri as indicated by the higher LC50 values. The combination of a low concentration of afidopyropen with O. sauteri offers an effective control approach for resistant A. gossypii, presenting a novel integrated pest management strategy.

Harnessing microbial communities for enhanced plant resilience against diseases

BackgroundPhytophthora infestans (P. infestans) and other plant infections threaten global agriculture and food security. This research incorporated Pseudomonas strains in microbial consortia to boost plant tolerance to P. infestans. The P. infestans fungus causes collapse and deterioration in many crops like potatoes by quickly spreading through their tubers and leaves in warm, damp weather.ObjectiveThe main goals were to identify effective Pseudomonas strains (those with high inhibitory activity), test their interactions (both inhibitory and synergistic), and determine the effect of inoculum density on disease treatment.MethodsWe used the following methodologies, from potato shoots and rhizosphere samples, Nine different strains of the antifungal bacterium Pseudomonas which were identified with preliminary antifungal activity. Bintje showed the greatest resistance to P. infestans among the three potato types that were examined. Methods utilized comprised: Quantification of bacterial density and growth, the inhibitory assays for P. infestans, experiments on leaf disc infections, Assessing the severity of an infection, Analysis of zoospore discharge. Studies on the integrated development of bacteria and valuation using statistical methods.ResultsThe study revealed the complexity of microbial interactions, host-specific reactions, and cell density's impact on treatment success. The study suggests using Pseudomonas strains as biocontrol agents, advancing sustainable agriculture. Microbial consortia disease management requires advanced methodologies, according to the findings. Investigating long-term ecological impacts on soil health, microbial diversity, and crop yield sustainability; validating identified microbial consortia through field trials; evaluating scalability and economic viability; and researching genetic engineering for customized disease control are recommended.ConclusionsResults suggest a shift from chemical pesticides to environmentally friendly plant disease control considering its ethical and regulatory implications. This study emphasizes the intricacy of microbial interactions and the need for informed biocontrol decisions. Their study also increases ecological knowledge and encourages innovative, sustainable worldwide agriculture.

Biocontrol and plant growth-promoting activities of airborne bacteria.

The potential of airborne bacteria as a sustainable alternative for agriculture was evaluated. Bacteria were isolated from air samples and evaluated for their plant growth-promoting (PGPB) and antifungal properties as biocontrol of phytopathogens. Results showed that diverse bacterial species, including Exiguobacterium, Rhodococcus, Kocuria, and Staphylococcus genera, exhibited PGPB activities such as phosphorus solubilization, siderophore production, and auxin production. Kocuria strains showed high auxin production. Rhodococcus sp. was observed to significantly promote root growth and the formation of beneficial biofilms on bean roots. Additionally, this bacterium opened the xylem vessels, facilitating the absorption of nutrients and water. Kocuria sp. strains exhibited high antifungal activity against Fusarium oxysporum and Phytophthora cinnamomi due to volatile organic compounds (VOCs) produced by these strains. Volatile profile revealed compounds such as dimethyl disulfide, pyrazines, and benzaldehyde derivatives associated with fungal growth inhibition. This study demonstrates the potential of airborne bacteria as both biofertilizers (producers of indole-3-acetic acid IAA, potassium, and phosphorus solubilizers, siderophore producers, and ammonium producers) and biocontrol agents (against the phytopathogenic fungus Fusarium oxysporum and Phytophthora cinnamomi).

Phytotoxic Potential of Methyl 4-Hydroxyphenylacetate Against Ageratina adenophora (Spreng.): Mechanistic Insights and Implications for Sustainable Weed Management

Current management of Ageratina adenophora, a highly invasive weed, relies on synthetic herbicides with environmental and resistance risks, necessitating eco-friendly alternatives. This study evaluated seven phenyl derivatives for phytotoxic activity against A. adenophora via in vitro bioassays. Methyl 4-hydroxyphenylacetate exhibited potent herbicidal efficacy, achieving 100% mortality in 2-month-old seedlings at 30 mM, 3-month-old seedlings at 100 mM, and wild adult/6-month-old plants at 200 mM within 48 h. At 250 mM, the compound reduced CO2 assimilation by 113.6% and stomatal conductance by 92.2%, indicating severe photosynthetic and transpirational disruption via oxidative stress-mediated chloroplast degradation and stomatal dysfunction. Hormonal profiling revealed significant declines in IAA-ASP, GA1, TZeatin, and TZR, alongside elevated ABA levels, while GA3 remained stable. These hormonal shifts likely drive stomatal closure and metabolic collapse, culminating in plant death. This study provides the first evidence of methyl 4-hydroxyphenylacetate’s dual-action phytotoxicity—targeting both stomatal regulation and hormonal balance—positioning it as a sustainable biocontrol agent for A. adenophora and potentially other invasive weeds.

Harnessing Natural Defenses Systemic Acquired Resistance (SAR) and Biocontrol in Sustainable Plant Protection

This research explores the integration of systemic acquired resistance (SAR) and biological control as sustainable alternatives to chemical-dependent approaches in plant protection. The study examines the molecular mechanisms of SAR, including pathogen recognition through pattern recognition receptors, MAPK signaling cascades, salicylic acid biosynthesis, and NPR1-mediated defense gene activation. SAR immune memory involves sophisticated epigenetic reprogramming, particularly histone modifications and DNA demethylation. Biocontrol agents operate through direct antagonism (e.g., Bacillus lipopeptides), nutrient competition (e.g., Pseudomonas siderophores), and niche exclusion (e.g., Trichoderma cell wall degradation). Despite their potential, both strategies face technical challenges: SAR efficacy varies with environmental conditions and genetic backgrounds, exhibits tissue-specific limitations, and triggers growth-defense trade-offs; biocontrol implementation suffers from poor field colonization, inter-strain antagonism, and scalability barriers. Recent innovations include nano-encapsulated SAR inducers that enhance induction efficiency by 40-60%, CRISPR-Cas9 fine-tuning of immune regulators, and intelligent molecular switches for precise defense activation. In biocontrol, synergistic Bacillus-Trichoderma consortia improve disease suppression by >50%, advanced formulation technologies enhance field persistence, and microbiome engineering systematically reshapes rhizosphere architecture. A three-phase technology roadmap proposes integrating these approaches through: (1) advanced formulations and screening platforms (short-term); (2) precision-engineered microbial communities and sophisticated molecular switches (medium-term); and (3) AI-driven plant health management platforms (long-term). This interdisciplinary research bridges fundamental science with practical applications, supporting sustainable agriculture and contributing to global food security and environmental goals.

Efficacy of Carum copticum extract as a green pesticide against groundnut seed beetle, Caryedon serratus

BackgroundCaryedon serratus (Olivier, 1790) (Coleoptera: Chrysomelidae) is a major groundnut pest that infests groundnut kernels. This study aimed to extract phytochemicals from Carum copticum using a Soxhlet extractor with methanol as an organic solvent and to evaluate their efficacy against C. serratus.ResultsMethanolic extract and its fractions showed significant adulticidal effects after 4 days of treatment, with 87.11 ± 2.21% and 70.10 ± 2.52%, respectively. A sex ratio imbalance, extension or reduction of developmental phases, decreased fecundity, and reduced fertility. In comparison to the control, the hexane fraction produced fecundity averages of 55.33 ± 2.01 eggs, and the ethyl acetate fraction produced an average of 41 ± 0.25 eggs, corresponding to reductions in spawning rates of 52.93% and 63.25%, respectively. Gas chromatography–mass spectrometry (GC–MS) were used to identify the major bioactive chemicals in C. copticum, and there was thymol (C10H14O), 1-methylbenzene (toluene, C10H14), 7-oxabicycloheptane (C10H18O), 1-pentene4-methyl (C6H12), and octane (C8H18). C. serratus was exposed to three distinct concentrations of the plant's crude and fractions of extract of organic solvents (hexane, ethyl acetate, and methanol).ConclusionsAll concentrations caused substantial mortality in C. serratus eggs and adults. This study shows that the efficacy of C. copticum is due to the active chemicals present in the extract that can be employed as a biocontrol agent against the major pest C. serratus.

Seasonal dynamics and enzyme profiles of diverse endophytic fungi in Sterculia urens Roxb.: insights into host-associated trends.

Sterculia urens Roxb., well known for its medicinal uses, remains largely unexplored in terms of its fungal endophytic communities. This study is the first comprehensive assessment of fungal endophyte diversity in S. urens. Sampling was conducted across different plant parts, seasons, and study sites. Molecular identification of fungal isolates was carried out using ITS sequencing. Additionally, colonization frequency and endophytic fungal diversity were analyzed. These isolates were evaluated for extracellular enzyme. A total of 31 different endophytic fungal species, representing 16 genera, were identified based on > 97% ITS sequence similarity. Colonization frequency was significantly influenced by season (P ≤ 0.0001), tissue type (P ≤ 0.0001), and site (P ≤ 0.0001). Diversity indices revealed a significant difference in relation to season and tissue type, but not with respect to location. Furthermore, this study reports, for the first time globally, the identification of Chaetomium meridiolense and Crinipellis wandoensis as endophytic fungi. Extracellular enzyme analysis revealed enzymatic activity in 29 morphotypes. The diverse enzymatic profiles of these fungal endophytes highlight their potential for various biotechnological applications. In addition, molecular and genomic investigations will provide a deeper understanding of the functional roles and symbiotic mechanisms of these fungal endophytes. Potential applications of this research include enhancing plant growth and stress tolerance, developing sustainable biofertilizers and biocontrol agents, promoting eco-friendly bioremediation strategies for dye-contaminated environments, and discovering novel enzymes suitable for industrial biotechnological processes.

Applications of endophytic fungi in plant disease control.

Diseases caused by pathogenic microorganisms (bacteria, fungi, and viruses) have resulted in the quality and yield of crops, which has seriously affected the development of the agricultural economy. The prolonged use of chemical fungicides for prevention and control can lead to environmental pollution, hindering the sustainable development of safe and eco-friendly agriculture while also promoting the resistance of pathogenic microorganisms. Nevertheless, non-pathogenic endophytic fungi that form symbiotic relationships with plants still exhibit significant antagonistic effects on pathogenic microorganisms, even in small concentrations. These fungi pose no threat to human health and are highly beneficial to the ecological environment, making them an ideal alternative to chemical fungicides. They are increasingly being recognized and have been subjected to comprehensive research. Based on this, this article summarizes the types of endophytic fungi with biocontrol effects in recent years. It focuses on elucidating the mechanisms of their biocontrol from physiological and molecular perspectives. In addition, the application and development challenges of biocontrol agents (BCAs) derived from these fungi are also discussed, including difficulties in elucidating their mechanisms of action during research and development, challenges in strain selection and improvement, difficulties in controlling environmental adaptability, and stringent storage conditions. The aim is to develop more effective endophytic fungi as emerging biocontrol resources for agricultural production.

Demographic and predatory parameters of a thelytokous phytoseiid mite as a biocontrol agent for spider mites.

The phytoseiid mite Neoseiulus agrestis (Karg) was recently collected from tetranychid-damaged maize plants in northwest China. The demographic parameters and functional response of N. agrestis were studied to evaluate its potential against spider mites. Starting with the capture of a solitary female mite, a laboratory population of N. agrestis was successfully established over multiple generations without any males being found. The life table experiment confirmed that N. agrestis indeed reproduced through thelytokous parthenogenesis and exhibited high fitness levels in both development and reproduction on four different diets consisting of spider mites Tetranychus urticae Koch and T. truncatus Ehara, astigmatid mites Aleuroglyphus ovatus (Tropeau), and cattail pollen Typha sp. The predator that preyed on two natural prey species exhibited a higher intrinsic rate of increase (T. urticae: 0.2501 day-1; T. truncatus: 0.2464 day-1). The functional responses of N. agrestis to different immature stages of T. urticae showed significantly higher average consumption rates (24.56 prey day-1) for larvae compared to other stages. Logistic regression analysis revealed that N. agrestis displayed a type II functional response across all immature stages of T. urticae, with the consumption rate increasing as prey density increased, until reaching a peak and eventually stabilizing at the plateau. The enhanced fitness of N. agrestis on both prey and pollen, along with its high consumption rate on tetranychid mites, highlights the potential of this thelytokous predator as a promising biocontrol agent and provides a novel approach for the management of spider mites in China. © 2025 Society of Chemical Industry.

In vitro Evaluation of Plant Growth Promoting Rhizobacteria Isolates against Fusarium oxysporum f. sp. ciceri

Chickpea (Cicer arietinum L.) is one of the most important pulse crops, contributing significantly to global pulse production. However, its productivity is severely constrained by Fusarium wilt, caused by Fusarium oxysporum f. sp. ciceri. The present study evaluates the antagonistic potential of native Plant Growth Promoting Rhizobacteria (PGPR) isolates collected from the Marathwada region, Maharashtra, against this pathogen. A total of 19 PGPR isolates were screened using an In vitro dual culture assay, where inhibition of fungal mycelial growth ranged from 39.63% to 86.67%. Among these, the isolate CPA2 exhibited the highest inhibition (86.67%), followed by CPP4 (85.22%) and CPJ1 (83.48%). The antagonistic activity of PGPR is attributed to the production of bioactive compounds such as siderophores, antibiotics, and hydrolytic enzymes that suppress pathogen growth. The study suggests that these native PGPR isolates have the potential to be developed as biocontrol agents for sustainable management of Fusarium wilt in chickpea cultivation.

Microbial diversity in coastal Casuarina equisetifolia forest and its potential in counteracting bacterial wilt infections.

Casuarina wilt is a destructive soil-borne disease caused by Ralstonia solanacearum species complex (RSSC). Recent large-scale outbreaks of Casuarina wilt in the coastal regions of Guangdong Province, China, suggest that the originally resistant Casuarina clones become susceptible to RSSC infection. This study aimed to investigate the microbial diversity of environmental microorganisms and its potential in biocontrol of this devastating disease. The results unveiled the dominant and common microbial species in Casuarina equisetifolia tree tissues, the rhizosphere soils and seawater in the vicinity of Casuarina equisetifolia forest belt. We also found a range of bacterial species with potent antimicrobial activities against Ralstonia pseudosolanacearum. Both the Casuarina endophyte A1-5, identified as Bacillus velezensis, and a combination biocontrol agent named CEP consisting of three mutually compatible soil isolates belonging to Citrobacter farmeri, Enterobacter aerogenes, and Pseudomonas mosselii, respectively, could effectively control the R. pseudosolanacearum infections on Casuarina and tomato. The active substance of strain A1-5 that inhibits the growth of R. pseudosolanacearum was purified and identified as surfactin C. The findings unveiled the microbial diversity and their specific distributions in the Guangdong coastal Casuarina equisetifolia forest areas, and present useful clues and resources for developing new strategies to prevent and control the Casuarina bacterial wilt. © 2025 Society of Chemical Industry.

EvSec22, a SNARE Protein, Regulates Hyphal Growth, Stress Tolerance, and Nematicidal Pathogenicity in Esteya vermicola

Bursaphelenchus xylophilus, the causative agent of pine wilt disease (PWD), poses a severe global threat to coniferous forests. Esteya vermicola, an endoparasitic nematophagous fungus, exhibits promising biocontrol potential against this pinewood nematode. The vesicular transport system, evolutionarily conserved in eukaryotes, is essential for fungal pathogenicity. Based on our genome sequence of E. vermicola CBS115803, we identified EvSec22, a gene encoding a SNARE protein implicated in vesicular transport process. This study investigates the role of EvSec22 in E. vermicola during nematode infection, utilizing our optimized gene knockout methodology. Infection assays revealed that EvSec22 deletion significantly impaired the pathogenicity of E. vermicola against B. xylophilus. Phenotypic analyses revealed that the ΔEvSec22 mutant exhibited suppressed hyphal growth, reduced conidiation, and abnormal septal spacing. Furthermore, the mutant showed significantly diminished tolerance to osmotic stress (sorbitol) and oxidative stress (hydrogen peroxide). Overall, the EvSec22 gene is associated with the virulence of E. vermicola CBS115803 against B. xylophilus, and its deletion also affects the normal growth of E. vermicola and its tolerance to abiotic stress. This study providing new insights into SNARE protein functions in fungal biocontrol agents.

A Streptomyces Agent for Biocontrol of Phytophthora Blight and Its Modulation of Rhizosphere Microbiomes in Passion Fruit.

Passion fruit and its seedlings hold significant economic value for both domestic and export markets in Taiwan. Among the diseases affecting passion fruit, Phytophthora blight, caused by Phytophthora nicotianae, severely impacts seedling survival and fruit production. This study aimed to develop a microbial agent to control Phytophthora blight by evaluating the potential of Streptomyces cavourensis strain PES4, isolated from rhizosphere soils in Taiwan. Additionally, the impact of strain PES4 application on microbial communities in the field was investigated. Our results demonstrated that S. cavourensis PES4 exhibited strong antagonistic activity against several bacterial, fungal, and oomycete pathogens, including P. nicotianae. Applying a 100-fold diluted culture broth of the strain PES4 significantly reduced the severity of Phytophthora blight on passion fruit leaves and fruits. Weekly applications of the strain PES4 throughout the growing season enhanced plant growth, yield, and fruit quality compared to the water control. Next-generation sequencing was used to analyze the influence of the strain PES4 application on the rhizosphere microbiome. The application of strain PES4 did not affect microbial richness or diversity but did alter the composition of bacterial and fungal communities. Specifically, the strain PES4 application reduced the relative abundances of Proteobacteria and Actinobacteria while increasing Acidobacteria, Verrucomicrobia, and Gemmatimonadetes at the phylum level. At the genus level, Rhodanobacter and Streptomyces populations increased. Regarding fungal communities, the strain PES4 application promoted the populations of Trichoderma and Mortierella, while Penicillium and Colletotrichum populations declined. In conclusion, S. cavourensis PES4 is a promising plant probiotic with both growth-promoting and biocontrol activities against Phytophthora blight in passion fruit. Its application can modulate the rhizosphere microbiome by enhancing beneficial bacterial and fungal populations and suppressing plant pathogenic ones, suggesting its potential as a sustainable biocontrol agent.

Role of Methyl thiobutyrate to Botrytis cinerea on cucumber

IntroductionBotrytis cinerea is a major agricultural pathogen that causes significant economic Q7 losses worldwide, affecting various crops, including cucumbers. Developing environmentally sustainable control strategies for this pathogen is crucial. Methyl thiobutyrate (MTB), a small organic molecule identified in the volatile organic compounds (VOCs) of biocontrol bacteria, has demonstrated potential in inhibiting B. cinerea both in vitro and in vivo.MethodsIn this study, the efficacy of MTB against cucumber gray mold disease was examined by assessing the in vitro and in vivo activities of MTB against B. cinerea and analyzing the transcriptomic data from MTB-treated cucumber leaves infected with B. cinerea.Results and discussionThis study shows that a 2 mg/mL solution of MTB inhibits B. cinerea growth by 98.6% in vitro. In vivo, MTB effectively reduces B. cinerea infection in cucumbers, alleviates necrotic damage in leaf tissues, and significantly reduces disease severity. Transcriptomic analysis reveals that MTB activates the plant immune responses by modulating key MAPK cascade signaling genes and upregulating basal defense genes, including chitinase, pectinase, and lignin biosynthesis genes. Furthermore, MTB influences the signaling pathways of salicylic acid (SA), jasmonic acid (JA), and ethylene (ET), resulting in the upregulation of genes such as peroxidase (POD), phenylalanine ammonia-lyase (PAL), lipoxygenase (LOX), and ethyleneresponsive transcription factors (ERFs). These results demonstrate the potential of MTB as an effective biocontrol agent against B. cinerea and provide valuable insights into its underlying mechanisms of action.