Optimizing sustainable control of Meloidogyne javanica in tomato plants through gamma radiation-induced mutants of Trichoderma harzianum and Bacillus velezensis.

This study investigates the efficacy of Trichoderma spp. and Bacillus spp., as well as their gamma radiation-induced mutants, as potential biological control agents against Meloidogyne javanica (Mj) in tomato plants. The research encompasses in vitro assays, greenhouse trials, and molecular identification methodologies to comprehensively evaluate the biocontrol potential of these agents. In vitro assessments reveal significant nematicidal activity, with Bacillus spp. demonstrating notable effectiveness in inhibiting nematode egg hatching (16-45%) and inducing second-stage juvenile (J2) mortality (30-46%). Greenhouse trials further confirm the efficacy of mutant isolates, particularly when combined with chitosan, in reducing nematode-induced damage to tomato plants. The combination of mutant isolates with chitosan reduces the reproduction factor (RF) of root-knot nematodes by 94%. By optimizing soil infection conditions with nematodes and modifying the application of the effective compound, the RF of nematodes decreases by 65-76%. Molecular identification identifies B. velezensis and T. harzianum as promising candidates, exhibiting significant nematicidal activity. Overall, the study underscores the potential of combined biocontrol approaches for nematode management in agricultural settings. However, further research is essential to evaluate practical applications and long-term efficacy. These findings contribute to the development of sustainable alternatives to chemical nematicides, with potential implications for agricultural practices and crop protection strategies.

Kosakonia oryziphila NP19 bacterium acts as a plant growth promoter and biopesticide to suppress blast disease in KDML105 rice.

This study demonstrates that root-associated Kosakonia oryziphila NP19, isolated from rice roots, is a promising plant growth-promoting bioagent and biopesticide for combating rice blast caused by Pyricularia oryzae. In vitro experiments were conducted on fresh leaves of Khao Dawk Mali 105 (KDML105) jasmine rice seedlings. The results showed that NP19 effectively inhibited the germination of P. oryzae fungal conidia. Fungal infection was suppressed across three different treatment conditions: rice colonized with NP19 and inoculated by fungal conidia, a mix of NP19 and fungal conidia concurrently inoculated on the leaves, and fungal conidia inoculation first followed by NP19 inoculation after 30 h. Additionally, NP19 reduced fungal mycelial growth by 9.9-53.4%. In pot experiments, NP19 enhanced the activities of peroxidase (POD) and superoxide dismutase (SOD) by 6.1-63.0% and 3.0-67.7%, respectively, indicating a boost in the plant's defense mechanisms. Compared to the uncolonized control, the NP19-colonized rice had 0.3-24.7% more pigment contents, 4.1% more filled grains per panicle, 26.3% greater filled grain yield, 34.4% higher harvest index, and 10.1% more content of the aroma compound 2-acetyl-1-pyrroline (2AP); for rice colonized with NP19 and infected with P. oryzae, these increases were 0.2-49.2%, 4.6%, 9.1%, 54.4%, and 7.5%, respectively. In field experiments, blast-infected rice that was colonized and/or inoculated with NP19 treatments had 15.1-27.2% more filled grains per panicle, 103.6-119.8% greater filled grain yield, and 18.0-35.8% higher 2AP content. A higher SOD activity (6.9-29.5%) was also observed in the above-mentioned rice than in the blast-infected rice that was not colonized and inoculated with NP19. Following blast infection, NP19 applied to leaves decreased blast lesion progression. Therefore, K. oryziphila NP19 was demonstrated to be a potential candidate for use as a plant growth-promoting bioagent and biopesticide for suppressing rice blast.

Enhancing tomato plant immune responses to Fusarium wilt disease by red seaweed Jania sp.

The novelty of this study lies in demonstrating a new approach to control wilt diseases using Jania ethyl acetate extract. In the current investigation, the potential impacts of Jania sp. ethyl acetate extract (JE) on Tomato Fusarium oxysporum wilt (FOW) have been studied. The in vitro antifungal potential of JE against F. oxysporum (FO) was examined. GC-MS investigation of the JE revealed that, the compounds possessing fungicidal action were Phenol,2-methoxy-4-(2-propenyl)-,acetate, Eugenol, Caryophyllene oxide, Isoespintanol, Cadinene, Caryophylla-4(12),8(13)-dien-5à-ol and Copaen. Jania sp. ethyl acetate extract exhibited strong antifungal potential against FO, achieving a 20 mmzone of inhibition. In the experiment, two different methods were applied: soil irrigation (SI) and foliar application (FS) of JE. The results showed that both treatments reduced disease index present DIP by 20.83% and 33.33% respectively. The findings indicated that during FOW, proline, phenolics, and the antioxidant enzymes activity increased, while growth and photosynthetic pigments decreased. The morphological features, photosynthetic pigments, total phenol content, and antioxidant enzyme activity of infected plants improved when JE was applied through soil or foliar methods. It is interesting to note that the application of JE had a substantially less negative effect on the isozymes peroxidase and polyphenol oxidase in tomato plants, compared to FOW. These reactions differed depending on whether JE was applied foliarly or via the soil. Finally, the use of Jania sp. could be utilized commercially as an ecologically acceptable method to protect tomato plants against FOW.

Multisource information fusion method for vegetable disease detection.

Automated detection and identification of vegetable diseases can enhance vegetable quality and increase profits. Images of greenhouse-grown vegetable diseases often feature complex backgrounds, a diverse array of diseases, and subtle symptomatic differences. Previous studies have grappled with accurately pinpointing lesion positions and quantifying infection degrees, resulting in overall low recognition rates. To tackle the challenges posed by insufficient validation datasets and low detection and recognition rates, this study capitalizes on the geographical advantage of Shouguang, renowned as the "Vegetable Town," to establish a self-built vegetable base for data collection and validation experiments. Concentrating on a broad spectrum of fruit and vegetable crops afflicted with various diseases, we conducted on-site collection of greenhouse disease images, compiled a large-scale dataset, and introduced the Space-Time Fusion Attention Network (STFAN). STFAN integrates multi-source information on vegetable disease occurrences, bolstering the model's resilience. Additionally, we proposed the Multilayer Encoder-Decoder Feature Fusion Network (MEDFFN) to counteract feature disappearance in deep convolutional blocks, complemented by the Boundary Structure Loss function to guide the model in acquiring more detailed and accurate boundary information. By devising a detection and recognition model that extracts high-resolution feature representations from multiple sources, precise disease detection and identification were achieved. This study offers technical backing for the holistic prevention and control of vegetable diseases, thereby advancing smart agriculture. Results indicate that, on our self-built VDGE dataset, compared to YOLOv7-tiny, YOLOv8n, and YOLOv9, the proposed model (Multisource Information Fusion Method for Vegetable Disease Detection, MIFV) has improved mAP by 3.43%, 3.02%, and 2.15%, respectively, showcasing significant performance advantages. The MIFV model parameters stand at 39.07 M, with a computational complexity of 108.92 GFLOPS, highlighting outstanding real-time performance and detection accuracy compared to mainstream algorithms. This research suggests that the proposed MIFV model can swiftly and accurately detect and identify vegetable diseases in greenhouse environments at a reduced cost.

Sustainable management of peanut damping-off and root rot diseases caused by Rhizoctonia solani using environmentally friendly bio-formulations prepared from batch fermentation broth of chitinase-producing Streptomyces cellulosae.

BACKGROUND: Soil-borne plant diseases represent a severe problem that negatively impacts the production of food crops. Actinobacteria play a vital role in biocontrolling soil-borne fungi. AIM AND OBJECTIVES: The target of the present study is to test the antagonistic activity of chitinase-producing Streptomyces cellulosae Actino 48 (accession number, MT573878) against Rhizoctonia solani. Subsequently, maximization of Actino 48 production using different fermentation processes in a stirred tank bioreactor. Finally, preparation of bio-friendly formulations prepared from the culture broth of Actino 48 using talc powder (TP) and bentonite in a natural as well as nano forms as carriers. Meanwhile, investigating their activities in reducing the damping-off and root rot diseases of peanut plants, infected by R. solani under greenhouse conditions. RESULTS: Actino 48 was found to be the most significant antagonistic isolate strain at p ≤ 0.05 and showed the highest inhibition percentage of fungal mycelium growth, which reached 97%. The results of scanning electron microscope (SEM) images analysis showed a large reduction in R. solani mycelia mass. Additionally, many aberrations changes and fungal hypha damages were found. Batch fermentation No. 2, which was performed using agitation speed of 200 rpm, achieved high chitinase activity of 0.1163 U mL- 1 min- 1 with a yield coefficient of 0.004 U mL- 1 min- 1 chitinase activity/g chitin. Nano-talc formulation of Actino 48 had more a significant effect compared to the other formulations in reducing percentages of damping-off and root rot diseases that equal to 19.05% and 4.76% with reduction percentages of 60% and 80%, respectively. The healthy survival percentage of peanut plants recorded 76.19%. Furthermore, the nano-talc formulation of Actino 48 was sufficient in increasing the dry weight of the peanut plants shoot, root systems, and the total number of peanut pods with increasing percentages of 47.62%, 55.62%, and 38.07%, respectively. CONCLUSION: The bio-friendly formulations of actinobacteria resulting from this investigation may play an active role in managing soil-borne diseases.

Actinomycetes isolated from rhizosphere of wild Coffea arabica L. showed strong biocontrol activities against coffee wilt disease.

Coffee, the second most traded commodity globally after petroleum and is the most exported cash crop of Ethiopia. However, coffee cultivation faces challenges due to fungal diseases, resulting in significant yield losses. The primary fungal diseases affecting coffee production include coffee berry disease, wilt disease (caused by Gibberella xylarioides), and coffee leaf rust. In this study, we aimed to isolate potentially antagonistic actinomycetes from the root rhizosphere of wild Coffea arabica plants in the Yayo coffee forest biosphere in southwestern Ethiopia. Soil samples were collected from the rhizosphere, and actinomycetes were selectively isolated and identified to the genus level by morphological, physiological, and biochemical characterization. These pure isolates were screened for their antagonistic activity against Gibberella xylarioides in vitro using a dual culturing method. Promising isolates demonstrating strong inhibition of fungal mycelial growth were further investigated through in vivo experiments using coffee seedlings. A total of 82 rhizobacteria were isolated. These isolates' inhibition of fungal mycelial growth varied from 0% to 83.3%. Among them, four isolates MUA26, MUA13, MUA52, and MUA14 demonstrated the highest percentage inhibition of fungal mycelial growth: 83.3%, 80%, 76.67%, and 73.3%, respectively. Seedlings inoculated with MUA13, MUA14, and MUA26 during the challenge inoculations (Rhizobacteria + Gibberella xylarioides) exhibited the lowest disease incidence compared to the infected fungi (P < 0.05). Notably, the seedlings inoculated with MUA26 demonstrated the highest disease control efficiency, reaching 83% (P < 0.05). MUA26 was found to produce extracellular enzymes, including chitinase, protease, and lipase, which acted as inhibitors. In summary, this study highlights that MUA26, among the actinomycete isolates, exhibited significant antagonistic activity against Gibberella xylarioides f.sp. coffea. Its efficacy in controlling coffee wilt disease, both in vitro and in vivo, positions it as a potential bioinoculant for managing coffee wilt disease.

Protective role of native root-associated bacterial consortium against root-knot nematode infection in susceptible plants.

Root-knot nematodes (RKNs) are a global menace to agricultural crop production. The role of root-associated microbes (RAMs) in plant protection against RKN infection remains unclear. Here we observe that cucumber (highly susceptible to Meloidogyne incognita) exhibits a consistently lower susceptibility to M. incognita in the presence of native RAMs in three distinct soils. Nematode infection alters the assembly of bacterial RAMs along the life cycle of M. incognita. Particularly, the loss of bacterial diversity of RAMs exacerbates plant susceptibility to M. incognita. A diverse range of native bacterial strains isolated from M. incognita-infected roots has nematode-antagonistic activity. Increasing the number of native bacterial strains causes decreasing nematode infection, which is lowest when six or more bacterial strains are present. Multiple simplified synthetic communities consisting of six bacterial strains show pronounced inhibitory effects on M. incognita infection in plants. These inhibitory effects are underpinned via multiple mechanisms including direct inhibition of infection, secretion of anti-nematode substances, and regulation of plant defense responses. This study highlights the role of native bacterial RAMs in plant resistance against RKNs and provides a useful insight into the development of a sustainable way to protect susceptible plants.

Antifungal metabolites produced by Pseudomonas hunanensis SPT26 effective in biocontrol of fusarium wilt of Lycopersicum esculentum under saline conditions.

In past few years, salinity has become one of the important abiotic stresses in the agricultural fields due to anthropogenic activities. Salinity is leading towards yield losses due to soil infertility and increasing vulnerability of crops to diseases. Fluorescent pseudomonads are a diverse group of soil microorganisms known for promoting plant growth by involving various traits including protecting crops from infection by the phytopathogens. In this investigation, salt tolerant plant growth promoting bacterium Pseudomonas hunanensis SPT26 was selected as an antagonist against Fusarium oxysporum, causal organism of fusarium wilt in tomato. P. hunanensis SPT26 was found capable to produce various antifungal metabolites. Characterization of purified metabolites using Fourier transform infrared spectroscopy (FT-IR) and liquid chromatography-electron spray ionization-mass spectrometry (LC-ESI/MS) showed the production of various antifungal compounds viz., pyrolnitrin, pyochelin and hyroxyphenazine by P. hunanensis SPT26. In the preliminary examination, biocontrol activity of purified antifungal metabolites was checked by dual culture method and results showed 68%, 52% and 65% growth inhibition by pyrolnitrin, 1- hydroxyphenazine and the bacterium (P. hunanensis SPT26) respectively. Images from scanning electron microscopy (SEM) revealed the damage to the mycelia of fungal phytopathogen due to production of antifungal compounds secreted by P. hunanensis SPT26. Application of bioinoculant of P. hunanensis SPT26 and purified metabolites significantly decreased the disease incidence in tomato and increased the plant growth parameters (root and shoot length, antioxidant activity, number of fruits per plant, etc.) under saline conditions. The study reports a novel bioinoculant formulation with the ability to promote plant growth parameters in tomato in presence of phytopathogens even under saline conditions.

Identification, fermentation optimization, and biocontrol efficacy of actinomycete YG-5 for the prevention of Alternaria leaf spot disease in star anise.

Star anise (Illicium verum), a valuable spice tree, faces significant threats from fungal diseases, particularly Alternaria leaf spot. This study investigates the potential of a soil-derived actinomycete strain, YG-5, as a biocontrol agent against Alternaria tenuissima, the causative pathogen on Alternaria leaf spot in star anise. Through comprehensive morphology, physiology, biochemistry, and genetic analyses, we identified the isolate as Streptomyces sp. YG-5. The strain exhibited broad-spectrum antimicrobial activity against several plant pathogens, with inhibition rates ranging between 36.47 to 80.34%. We systematically optimized the fermentation conditions for YG-5, including medium composition and cultivation parameters. The optimized process resulted in an 89.56% inhibition rate against A. tenuissima, a 14.72% improvement over non-optimized conditions. Notably, the antimicrobial compounds produced by YG-5 demonstrated stability across various temperatures, pH levels, and UV irradiation. In vivo efficacy trials showed promising results, with YG-5 fermentation broth reducing Alternaria leaf spot incidence on star anise leaves by 56.95%. These findings suggest that Streptomyces sp. YG-5 holds significant potential as a biocontrol agent against Alternaria leaf spot in star anise cultivation, offering a sustainable approach to disease management in this valuable crop.

Interventions based on alternative and sustainable strategies for postharvest control of anthracnose and maintain quality in tropical fruits.

Colletotrichum spp. is a phytopathogen causing anthracnose in a variety of tropical fruits. Strategies used to control postharvest diseases in tropical fruits typically rely on the use of synthetic fungicides, which have stimulated the emergence of resistant pathogens. Safer alternative strategies to control anthracnose in tropical fruits have been described in the literature. This review presents and discusses the main innovative interventions concerning the application of sustainable alternative strategies in the postharvest control of pathogenic Colletotrichum species in tropical fruits, with a particular emphasis on the studies published in the last 5 years. The available studies have shown the use of various methods, including physical barriers, natural antimicrobials, and biological control with antagonistic microorganisms, to reduce anthracnose lesion severity and incidence in tropical fruits. The available literature showed high inhibitory activity in vitro, reduced anthracnose incidence and lesion diameter, and total disease inhibition in tropical fruits. Most studies focused on the inhibition of Colletotrichum gloeosporioides on avocado, papaya, and mango, as well as of Colletotrichum musae on banana; however, the inhibition of other Colletotrichum species was also demonstrated. The application of emerging sustainable alternative methods, including natural antimicrobial substances, also stimulated the induction of defense systems in tropical fruits, including enzymatic activity, such as polyphenol oxidase, peroxidase, and phenylalanine ammonia-lyase. The retrieved data helped to understand the current state of the research field and reveal new perspectives on developing efficient and sustainable intervention strategies to control pathogenic Colletotrichum species and anthracnose development in tropical fruits.

Bacillus velezensis: a versatile ally in the battle against phytopathogens-insights and prospects.

The escalating interest in Bacillus velezensis as a biocontrol agent arises from its demonstrated efficacy in inhibiting both phytopathogenic fungi and bacteria, positioning it as a promising candidate for biotechnological applications. This mini review aims to offer a comprehensive exploration of the multifaceted properties of B. velezensis, with particular focus on its beneficial interactions with plants and its potential for controlling phytopathogenic fungi. The molecular dialogues involving B. velezensis, plants, and phytopathogens are scrutinized to underscore the intricate mechanisms orchestrating these interactions. Additionally, the review elucidates the mode of action of B. velezensis, particularly through cyclic lipopeptides, highlighting their importance in biocontrol and promoting plant growth. The agricultural applications of B. velezensis are detailed, showcasing its role in enhancing crop health and productivity while reducing reliance on chemical pesticides. Furthermore, the review extends its purview in the industrial and environmental arenas, highlighting its versatility across various sectors. By addressing challenges such as formulation optimization and regulatory frameworks, the review aims to chart a course for the effective utilization of B. velezensis. KEY POINTS: • B. velezensis fights phytopathogens, boosting biotech potential • B. velezensis shapes agri-biotech future, offers sustainable solutions • Explores plant-B. velezensis dialogue, lipopeptide potential showcased.

Investigation of 2,4-Dihydroxylaryl-Substituted Heterocycles as Inhibitors of the Growth and Development of Biotrophic Fungal Pathogens Associated with the Most Common Cereal Diseases.

Climate change forces agriculture to face the rapidly growing virulence of biotrophic fungal pathogens, which in turn drives researchers to seek new ways of combatting or limiting the spread of diseases caused by the same. While the use of agrochemicals may be the most efficient strategy in this context, it is important to ensure that such chemicals are safe for the natural environment. Heterocyclic compounds have enormous biological potential. A series of heterocyclic scaffolds (1,3,4-thiadiazole, 1,3-thiazole, 1,2,4-triazole, benzothiazine, benzothiadiazine, and quinazoline) containing 2,4-dihydroxylaryl substituents were investigated for their ability to inhibit the growth and development of biotrophic fungal pathogens associated with several important cereal diseases. Of the 33 analysed compounds, 3 were identified as having high inhibitory potential against Blumeria and Puccinia fungi. The conducted research indicated that the analysed compounds can be used to reduce the incidence of fungal diseases in cereals; however, further thorough research is required to investigate their effects on plant-pathogen systems, including molecular studies to determine the exact mechanism of their activity.

Fungicide-Loaded Liposomes for the Treatment of Fungal Diseases in Agriculture: An Assessment of Botrytis cinerea.

In this work, liposomes loaded with the fungicide, Fludioxonil (FLUD), for the containment of fungal diseases in agriculture were developed. Three types of vesicles with different compositions were compared: (I) plain vesicles, composed of soy phosphatidylcholine and cholesterol; (II) PEG-coated vesicles, with an additional polyethylene glycol coating; and (III) cationic vesicles, containing didodecyldimethylammonium bromide. Nanometric-sized vesicles were obtained both by the micelle-to-vesicle transition method and by the extrusion technique, and encapsulation efficiency, drug loading content, and Zeta potential were determined for all the samples. The extruded and PEGylated liposomes were the most stable over time and together with the cationic ones showed a significant prolonged FLUD release capacity. The liposomes' biological activity was evaluated on conidial germination, germ tube elongation and colony radial growth of the ascomycete Botrytis cinerea, a phytopathogenic fungus affecting worldwide many important agricultural crops in the field as well as in the postharvest phase. The extruded and PEGylated liposomes showed greater effectiveness in inhibiting germ tube elongation and colony radial growth of the fungal pathogen, even at 0.01 µg·mL-1, the lowest concentration assessed.

Deciphering fungicide resistance in Phytophthora: mechanisms, prevalence, and sustainable management approaches.

The genus Phytophthora contains more than 100 plant pathogenic species that parasitize a wide range of plants, including economically important fruits, vegetables, cereals, and forest trees, causing significant losses. Global agriculture is seriously threatened by fungicide resistance in Phytophthora species, which makes it imperative to fully comprehend the mechanisms, frequency, and non-chemical management techniques related to resistance mutations. The mechanisms behind fungicide resistance, such as target-site mutations, efflux pump overexpression, overexpression of target genes and metabolic detoxification routes for fungicides routinely used against Phytophthora species, are thoroughly examined in this review. Additionally, it assesses the frequency of resistance mutations in various Phytophthora species and geographical areas, emphasizing the rise of strains that are resistant to multiple drugs. The effectiveness of non-chemical management techniques, including biological control, host resistance, integrated pest management plans, and cultural practices, in reducing fungicide resistance is also thoroughly evaluated. The study provides important insights for future research and the development of sustainable disease management strategies to counter fungicide resistance in Phytophthora species by synthesizing current information and identifying knowledge gaps.

Bioactivity of silverleaf nightshade (Solanum elaeagnifolium Cav.) berries parts against Galleria mellonella and Erwinia carotovora and LC-MS chemical profile of its potential extract.

Natural products received much attention as an environmentally beneficial solution for pest management. Therefore, the extracts of invasive silverleaf nightshade (Solanum elaeagnifolium Cav.) weeds using their berries parts (seeds, peels and mucilage) supported by bioassay-guided fractionation were tested against both the greater wax moth (Galleria mellonella) and Erwinia carotovora pv. carotovora causes of the blackleg of potatoes. The seeds and peels of S. elaeagnifolium were successively extracted by maceration using dichloromethane (DCM), ethyl acetate (EtOAc), and ethanol (EtOH), respectively. While, its mucilage was extracted using EtOAc. The successive EtOH extract of the plant seeds had promising inhibition efficacy and the best minimal inhibition concentration (MIC) of 50 µg/ml against E. Carotovora amongst other extracts (DCM and EtOAc of the plant berries parts). Depending on dose response activity, EtOH extract had G. mellonella larval mortality and pupal duration rates (LC50; 198.30 and LC95; 1294.73 µg/ml), respectively. Additionally, this EtOH extract of seeds was fractionated using preparative TLC to three characteristic bands. The insecticidal and bacterial activities of these isolated bands (SEA, SEB, and SEC) were evaluated at a dose of 100 µg/ml, causing mortality by 48.48, 62.63 and 92.93% (G. mellonella larvae) and inhibition by 15.22, 0.00 and 31.66 mm (E. carotovora), respectively. Moreover, the separated major three bands were tentatively identified using LC-ESI-MS analysis revealing the presence of two phenolic acids; chlorogenic acid (SEA) and dicaffeoyl quinic acid (SEB) in addition to one steroidal saponin (SEC) annotated as borassoside E or yamoscin. Finally, the plant seeds' successive EtOH extract as well as its active constituents, exhibited potential broad-spectrum activity and the ability to participate in future pest management initiatives. A field study is also recommended to validate its bio-efficacy against selected pests and to develop its formulations.

Study on the inhibitory mechanism of fig leaf extract against postharvest Fusarium in melon.

The objective of this study was to explore the fungistatic mechanism of fig leaf extract against Fusarium and to provide a theoretical basis for the development of new plant-derived fungicides. Methods: The fungistaticity of fig leaf extract were analyzed by the ring of inhibition method. Fusarium equiseti was selected as the target for analyzing its fungistatic mechanism in terms of mycelial morphology, ultrastructure, cell membrane permeability, membrane plasma peroxidation, reactive oxygen species (ROS) content and changes in the activity of protective enzymes. The effect of this extract was verified in melon, and its components were determined by metabolite analysis using ultraperformance liquid chromatography‒mass spectrometry (UPLC‒MS). Results: Fig leaf extract had an obvious inhibitory effect on Fusarium, and the difference was significant (P < 0.05) or highly significant (P < 0.01). Scanning and transmission electron microscopy revealed that F. equiseti hyphae exhibited obvious folding, twisting and puckering phenomena, resulting in an increase in the cytoplasmic leakage of spores, interstitial plasma, and the concentration of the nucleus, which seriously damaged the integrity of the fungal cell membrane. This phenomenon was confirmed by propidium iodide (PI) and fluorescein diacetate (FAD) staining, cell membrane permeability and malondialdehyde (MDA) content. Fig leaf extract also induced the mycelium to produce excessive H2O2,which led to lipid peroxidation of the cell membrane, promoted the accumulation of MDA, accelerated protein hydrolysis, induced an increase in antioxidant enzyme activity, and disrupted the balance of ROS metabolism; these findings showed that fungal growth was inhibited, which was verified in melons. A total of 1,540 secondary metabolites were detected by broad-targeted metabolomics, among which the fungistatic active substances flavonoids (15.45%), phenolic acids (15%), and alkaloids (10.71%) accounted for a high percentage and the highest relative content of these substances 1,3,7,8-tetrahydroxy-2- prenylxanthone, 8-hydroxyquinoline and Azelaic acid were analysed for their antimicrobial, anti-inflammatory, antioxidant, preventive effects against plant diseases and acquisition of resistance by plants. This confirms the reason for the fungicidal properties of fig leaf extracts. Conclusion: Fig leaf extract has the potential to be developed into a plant-derived fungicide as a new means of postharvest pathogen prevention and control in melon.

Identifying highly connected sites for risk-based surveillance and control of cucurbit downy mildew in the eastern United States.

Objective: Surveillance is critical for the rapid implementation of control measures for diseases caused by aerially dispersed plant pathogens, but such programs can be resource-intensive, especially for epidemics caused by long-distance dispersed pathogens. The current cucurbit downy mildew platform for monitoring, predicting and communicating the risk of disease spread in the United States is expensive to maintain. In this study, we focused on identifying sites critical for surveillance and treatment in an attempt to reduce disease monitoring costs and determine where control may be applied to mitigate the risk of disease spread. Methods: Static networks were constructed based on the distance between fields, while dynamic networks were constructed based on the distance between fields and wind speed and direction, using disease data collected from 2008 to 2016. Three strategies were used to identify highly connected field sites. First, the probability of pathogen transmission between nodes and the probability of node infection were modeled over a discrete weekly time step within an epidemic year. Second, nodes identified as important were selectively removed from networks and the probability of node infection was recalculated in each epidemic year. Third, the recurring patterns of node infection were analyzed across epidemic years. Results: Static networks exhibited scale-free properties where the node degree followed a power-law distribution. Betweenness centrality was the most useful metric for identifying important nodes within the networks that were associated with disease transmission and prediction. Based on betweenness centrality, field sites in Maryland, North Carolina, Ohio, South Carolina and Virginia were the most central in the disease network across epidemic years. Removing field sites identified as important limited the predicted risk of disease spread based on the dynamic network model. Conclusions: Combining the dynamic network model and centrality metrics facilitated the identification of highly connected fields in the southeastern United States and the mid-Atlantic region. These highly connected sites may be used to inform surveillance and strategies for controlling cucurbit downy mildew in the eastern United States.

Vernicia fordii leaf extract inhibited anthracnose growth by downregulating reactive oxygen species (ROS) levels in vitro and in vivo.

Background: Colletotrichum fructicola is a predominant anthracnose species in Camellia oleifera, causing various adverse effects. Traditional intercropping Vernicia fordii with C. oleifera may enhance anthracnose resistance, but the mechanism remains elusive. Methods: We utilized UPLC-MS/MS and acid-base detection to identify the major antimicrobial alkaloid components in the V. fordii leaf extract. Subsequently, by adding different concentrations of V. fordii leaf extract for cultivating C. fructicola, with untreated C. fructicola as a control, we investigated the impact of the V. fordii leaf extract, cell wall integrity, cell membrane permeability, MDA, and ROS content changes. Additionally, analysis of key pathogenic genes of C. fructicola confirmed that the V. fordii leaf extract inhibits the growth of the fungus through gene regulation. Results: This study discovered the alkaloid composition of V. fordii leaf extract by UPLC-MS/MS and acid-base detection, such as trigonelline, stachydrine, betaine, and O-Phosphocholine. V. fordii leaf extract successfully penetrated C. fructicola mycelia, damaged cellular integrity, and increased ROS and MDA levels by 1.75 and 2.05 times respectively, thereby inhibiting C. fructicola proliferation. By analyzing the key pathogenic genes of C. fructicola, it was demonstrated that the antifungal function of V. fordii leaf extract depends mainly on the regulation of RAB7 and HAC1 gene expression. Therefore, this study elucidates the mechanism of V. fordii -C. oleifera intercropping in strengthening anthracnose resistance in C. oleifera, contributing to efficient C. oleifera cultivation.

Bio-perfume guns: Antifungal volatile activity of Bacillus sp. LNXM12 against postharvest pathogen Botrytis cinerea in tomato and strawberry.

Gray mold disease, caused by Botrytis cinerea is a major postharvest disease impacting fruits such as strawberries and tomatoes. This study explores the use of volatile organic compounds (VOCs) produced by Bacillus spp. as eco-friendly biocontrol agents against B. cinerea. In vitro experiments demonstrated that VOCs from Bacillus sp. LNXM12, B. thuringiensis GBAC46, and B. zhanghouensis LLTC93-VOCs inhibited fungal growth by 61.2%, 40.5%, and 21.6%, respectively, compared to the control. LNXM12 was selected for further experiments due to its highest control efficacy of 58.3% and 76.6% on tomato and strawberry fruits, respectively. The LNXM12 VOCs were identified through gas chromatography-mass spectrometry (GC-MS) analysis, and 22 VOCs were identified. Synthetic VOCs with the highest probability percentage, namely ethyloctynol, 3-methyl-2-pentanone (3M2P), 1,3-butadiene-N, N-dimethylformamide (DMF), and squalene were used in experiments. The results showed that the synthetic VOCs ethyloctynol and 3M2P were highly effective, with an inhibition rate of 56.8 and 57.1% against fungal mycelium radial growth at 120 µg/mL on agar plates. Trypan blue staining revealed strongly disrupted, deeper blue, and lysed mycelium in VOC-treated B. cinerea. The scanning and transmission electron microscope (SEM and TEM) results showed that fungal mycelium was smaller, irregular, and shrunken after synthetic VOC treatments. Furthermore, the synthetic VOCs Ethyloctynol and 3M2P revealed high control efficacy on tomatoes and strawberries infected by B. cinerea. The control efficacy on leaves was 67.2%, 66.1% and 64.5%, 78.4% respectively. Similarly, the control efficiency on fruits was 45.5%, 67.3% and 46.3% 65.1%. The expression of virulence genes in B. cinerea was analyzed, and the results revealed that selected genes BcSpl1, BcXyn11A, BcPG2, BcNoxB, BcNoxR, and BcPG1 were downregulated after VOCs treatment. The overall result revealed novel mechanisms by which Bacillus sp. volatiles control postharvest gray mold disease.

A potent endophytic fungus Purpureocillium lilacinum YZ1 protects against Fusarium infection in field-grown wheat.

Fusarium diseases pose a severe global threat to major cereal crops, particularly wheat. Existing biocontrol strains against Fusarium diseases are believed to primarily rely on antagonistic mechanisms, but not widely used under field conditions. Here, we report an endophytic fungus, Purpureocillium lilacinum YZ1, that shows promise in combating wheat Fusarium diseases. Under glasshouse conditions, YZ1 inoculation increased the survival rate of Fusarium graminearum (Fg)-infected wheat seedlings from 0% to > 60% at the seedling stage, and reduced spikelet infections by 70.8% during anthesis. In field trials, the application of YZ1 resulted in an impressive 89.0% reduction in Fg-susceptible spikelets. While a slight antagonistic effect of YZ1 against Fg was observed on plates, the induction of wheat systemic resistance by YZ1, which is distantly effective, non-specific, and long-lasting, appeared to be a key contributor to YZ1's biocontrol capabilities. Utilizing three imaging methods, we confirmed YZ1 as a potent endophyte capable of rapid colonization of wheat roots, and systematically spreading to the stem and leaves. Integrating dual RNA-Seq, photosynthesis measurements and cell wall visualization supported the link between YZ1's growth-promoting abilities and the activation of wheat systemic resistance. In conclusion, endophytes such as YZ1, which exhibits non-antagonistic mechanisms, hold significant potential for industrial-scale biocontrol applications.