Search

Plant diseases caused by soil-borne fungi and oomycetes significantly reduce yield and quality of many crops in the agricultural systems and are difficult to control. We herein examine Pseudomonas rhodesiae HAI-0804, a bacterial biological control agent that was originally developed for control of bacterial diseases on the surface of vegetables, and assessed its efficacy at controlling soil-borne diseases caused by oomycetes. Strain HAI-0804 did not exhibit detectable antibiotic activity toward Pythium ultimum , a causal agent of damping-off and root rot; however, it effectively protected against Pythium damping-off and root rot in cucumber. Exogenous glutamate enhanced the efficacy of biocontrol, the production of siderophore pyoverdine, root colonization in cucumber plants, and the ratio of biofilm formation to planktonic cells. The epiphytic fitness of strain HAI-0804 appears to contribute to plant protection efficacy against a broad spectrum of pathogens for both above-ground plant parts and the rhizosphere. [ABSTRACT FROM AUTHOR]

Root exudates serve as a bridge connecting plant roots and rhizosphere microbes, playing a key role in influencing the assembly and function of the rhizobiome. Recent studies have fully elucidated the role of root exudates in recruiting rhizosphere microbes to enhance plant performance, particularly in terms of plant resistance to soil-borne pathogens; however, it should be noted that the composition and amount of root exudates are primarily quantitative traits regulated by a large number of genes in plants. As a result, there are knowledge gaps in understanding the contribution of the rhizobiome to soil-borne plant disease resistance and the ternary link of plant genes, root exudates, and disease resistance-associated microbes. Advancements in technologies such as quantitative trait loci (QTL) mapping and genome-wide association studies (GWAS) offer opportunities for the identification of genes associated with quantitative traits. In the present review, we summarize recent studies on the interactions of plant and rhizosphere microbes through root exudates to enhance soil-borne plant disease resistance and also highlight methods for quantifying the contribution of the rhizobiome to plant disease resistance and identifying the genes responsible for recruiting disease resistance-associated microbes through root exudates. [ABSTRACT FROM AUTHOR]

Grapevine crown gall (GCG), a soil-borne plant disease caused by tumorigenic Allorhizobium vitis (TAV) (=tumorigenic Rhizobium vitis) strains, poses a significant threat to grapevines worldwide. Recently, outbreaks of GCG have been reported in several vineyards, necessitating investigation into potential alternative infection pathways beyond soil transmission. The spatiotemporal distribution of GCG in vineyards from 2020 to 2022 was analyzed using the binary power law (BPL) model, with variations in quadrat shapes. Both total and newly observed diseased plants exhibited an aggregated distribution, indicating that new infections clustered around existing diseased plants, with secondary infections appearing as independent cluster points. This study provides evidence that infected pruning tools can transmit the pathogen to healthy grapevines and that TAV inoculation through spraying contributes more to GCG incidence than planting in infected soil alone. This represents the first documented case of secondary above-ground TAV infection contributing to GCG in commercial vineyards. [ABSTRACT FROM AUTHOR]

Simple Summary: Fritillaria ussuriensis holds significance as one of the most crucial traditional Chinese medicinal plants utilized in the prevention and treatment of various human diseases. Currently, its availability depends on large-scale cultivation, with wilt disease posing a significant challenge during the planting process. Endophytic microorganisms within the plants play a vital role in maintaining plant health; however, disparities in microbial communities between diseased and healthy plants remain unclear. This study aimed to compare these variances, elucidate the distribution patterns of pathogens, and identify antagonistic microorganisms with biocontrol properties. The research revealed that these microorganisms were effective not only in combatting wilt in F. ussuriensis but also in controlling rot in other plants within the Liliaceae family. This discovery offers a promising avenue for the sustainable management and prevention of soil-borne diseases in plants. The cultivation of Fritillaria ussuriensis faces challenges due to the prevalent Fritillaria wilt disease, hindering large-scale production. To address this, we aimed to understand the disease's characteristics and develop effective prevention measures. Microbial communities of diseased F. ussuriensis plants were analyzed, pathogenic and antagonistic strains were screened, and biocontrol feasibility was tested. We identified Botryotinia predominance in aboveground parts and variations in Mrakia, Humicola, llyonectria, and Fusarium in underground parts. The pathogens Fusarium oxysporum IFM-1 and Fusarium solani IFM-52 isolated from diseased F. ussuriensis not only caused severe Fritillaria wilt but were also pathogenic to Lilium lancifolium and Allium cepa var. aggregatum in Liliaceae. The antagonistic Bacillus tequilensis LFM-30 and Trichoderma koningiopsis IFM-47 isolated from diseased plants significantly alleviated plant wilt and showed promise in preventing wilt disease caused by Fusarium in Liliaceae plants. Our study highlights distinct microbial differences between healthy and diseased F. ussuriensis and underscores the pathogenicity of Fusarium. Using T. koningiopsis and B. tequilensis either singly or in combination could offer effective biocontrol against F. solani and F. oxysporum, benefiting F. ussuriensis and related Liliaceae plants. [ABSTRACT FROM AUTHOR]

Panax plants are known for their significant medicinal and economic value. Being perennial, they are prone to soil-borne diseases during cultivation. However, there has been limited research on the pathogenesis of soil-borne diseases and the diversity of pathogens. While biological control has gained attention for its efficacy and environmental benefits, the factors affecting its efficiency still need thorough evaluation. This review summarizes the influence of biotic factors, such as pathogens and hosts, and environmental factors on the occurrence of soil-borne diseases and pathogen diversity. Additionally, we synthesized bacterial, actinobacterial, and fungal diversity for the biocontrol of soil-borne diseases and their functional mechanisms. Moreover, the review delves into the factors influencing the efficacy of biocontrol, including microbial species, the inoculation method and inoculation volume, and inoculant composition. This article serves as a valuable resource for enhancing the efficiency of biological control and optimizing strategies for managing soil-borne diseases in Panax cultivation in the future. [ABSTRACT FROM AUTHOR]

Grapevine crown gall (GCG), a soil-borne plant disease caused by tumorigenic Allorhizobium vitis (TAV) (=tumorigenic Rhizobium vitis) strains, poses a significant threat to grapevines worldwide. Recently, outbreaks of GCG have been reported in several vineyards, necessitating investigation into potential alternative infection pathways beyond soil transmission. The spatiotemporal distribution of GCG in vineyards from 2020 to 2022 was analyzed using the binary power law (BPL) model, with variations in quadrat shapes. Both total and newly observed diseased plants exhibited an aggregated distribution, indicating that new infections clustered around existing diseased plants, with secondary infections appearing as independent cluster points. This study provides evidence that infected pruning tools can transmit the pathogen to healthy grapevines and that TAV inoculation through spraying contributes more to GCG incidence than planting in infected soil alone. This represents the first documented case of secondary above-ground TAV infection contributing to GCG in commercial vineyards. [ABSTRACT FROM AUTHOR]

Bacterial wilt (BW) is a devastating plant disease caused by the soil-borne bacterium Ralstonia solanacearum species complex (Rssc). Numerous efforts have been exerted to control BW, but effective, economical, and environmentally friendly approaches are still not available. Bacteriophages are a promising resource for the control of bacterial diseases, including BW. So, in this study, a crop BW pathogen of lytic bacteriophage was isolated and named PQ43W. Biological characterization revealed PQ43W had a short latent period of 15 min, 74 PFU/cell of brust sizes, and good stability at a wide range temperatures and pH but a weak resistance against UV radiation. Sequencing revealed phage PQ43W contained a circular double-stranded DNA genome of 47,156 bp with 65 predicted open reading frames (ORFs) and genome annotation showed good environmental security for the PQ43W that no tRNA, antibiotic resistance, or virulence genes contained. Taxonomic classification showed PQ43W belongs to a novel genus of subfamily Kantovirinae under Caudoviricetes. Subsequently, a dose of PQ43W for phage therapy in controlling crop BW was determined: 108 PFU*20 mL per plant with non-invasive irrigation root application twice by pot experiment. Finally, a field experiment of PQ43W showed a significantly better control effect in crop BW than the conventional bactericide Zhongshengmycin. Therefore, bacteriophage PQ43W is an effective bio-control resource for controlling BW diseases, especially for crop cultivation. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Simple Summary: Black soldier fly larvae (BSFL) frass, the residual material resulting from the bioconversion of organic matter by BSFL, is gaining attention as a potential organic amendment for plant growth. Studies have reported the potential of BSFL frass to replace commercial inorganic fertilizers in food crops. Besides improving soil fertility, BSFL frass was recently shown to have antifungal activity against different fungal plant pathogens, suggesting that it could suppress fungal plant diseases. This study investigated the effect of BSFL frass derived from BSFL reared on a diet composed of fruit/vegetable/bakery/brewery residues (FVBB diet) and on the Gainesville diet (GV diet) on the development of Fusarium wilt in tomato plants caused by the fungus Fusarium oxysporum f. sp. lycopersici (FOL). The results show that frass from BSFL reared on the GV diet, treated with heat (70 °C, 1 h) or not, inhibited FOL root colonization and reduced the severity of the disease to a far greater extent than frass from BSFL reared on a FVBB diet and commercial compost made of peat, seaweed, and shrimps. This study suggests that BSFL frass, depending on the larval rearing diet, could serve as a soil amendment to control FOL in tomato plants, opening new avenues of research for the valorization of BSFL frass. This study investigated the effect of black soldier fly larvae (BSFL) frass derived from BSFL reared on a diet composed of fruit/vegetable/bakery/brewery residues (FVBB diet) and on the Gainesville diet (GV diet) on the development of tomato (Solanum lycopersicum) Fusarium wilt caused by Fusarium oxysporum f. sp. lycopersici (FOL). Tomato plants were grown in a substrate inoculated with FOL that was amended (10%, v:v) or not (control) with either a commercial compost, pasteurized (70 °C for 1 h) frass from BSFL reared on a FVBB diet, non-pasteurized frass from BSFL reared on a FVBB diet, pasteurized frass from BSFL reared on the GV diet, or non-pasteurized frass from BSFL reared on the GV diet. The results show that frass from BSFL reared on the GV diet, irrespective of pasteurization, inhibited FOL root colonization and reduced the severity of tomato Fusarium wilt to a far greater extent than frass from BSFL reared on a FVBB diet and commercial compost made of peat, seaweed, and shrimps. This study suggests that BSFL frass, depending on the larval rearing diet, has the potential to serve as a pasteurized or non-pasteurized soil amendment with prophylactic properties against FOL in tomato plants, opening new avenues of research for the valorization of BSFL frass. [ABSTRACT FROM AUTHOR]

BACKGROUND: Entomophagous fungi (EPF) not only directly kill insect pests, but also colonize plants and improve their resistance against pests. However, most previous research has focused on Beauveria bassiana and Metarhizium anisopliae, and there are few reports on whether other EPF can enhance resistance against pests via endogenous colonization. Herein, an EPF strain was isolated from diseased larvae of Spodoptera litura in a soybean field, and subjected to genome‐wide sequencing at the chromosomal level. The pathogenicity of the isolate toward various pest insects was evaluated, and the ability to colonize plants and induce resistance against phytopathogens and insect pests was tested. RESULTS: The purified isolate was identified as M. rileyi and designated MrS1Gz1–1. Biological assays revealed its strong pathogenicity toward five insect pests belonging to Lepidoptera and Hemiptera. Furthermore, the strain inhibited the growth of soil‐borne plant disease caused by Sclerotinia sclerotiorum in vitro. It colonized plants as an endophyte via soil application, thereby inducing plant resistance‐related genes against phytopathogen infection, and it disrupted the feeding selectivity of S. litura larvae. CONCLUSION: M. rileyi MrS1Gz1–1 has potential as a broad‐spectrum microbial control agent that can induce resistance against phytopathogens and insect pests feeding as an endotype. The complete genome provides a valuable resource for exploring host interactions. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Vermicompost is applied as a soil amendment to promote plant growth and yield. It also helps to significantly reduce the incidence of soil-borne diseases. However, its efficiency depends on the type of earthworm from which it is formed. The current study aims to compare the effects of two vermicompost types derived from African nightcrawler (AF) and Tiger worm (TG) as a soil amendment to evaluate its potential for suppressing damping-off disease both in vitro and in vivo. It also aims to determine the effects of both vermicompost types on the growth and yield-related traits of potted Thai vegetable soybean [Glycine max (L.) Merrill] variety "Chiang Mai 84–2" grown under greenhouse conditions when amended to the soil at various application rates (1%, 2%, 3% w/w). AF vermicompost exhibited better suppression of damping-off disease than TG vermicompost in vitro and under greenhouse conditions. AF vermicompost performed significantly greater suppressive efficacy on the mycelial growth of Athelia rolfsii in vitro than TG vermicompost, indicated by 50% and 16% inhibition, respectively. Damping-off incidence on vegetable soybean seedlings grown in soil amended with AF vermicompost was significantly lower (21%) than in soil amended with TG vermicompost (32%) under greenhouse conditions. With an increased application rate of 1% to 2% or 3% for each vermicompost type, plant yields significantly enhanced, with no significant variations among the 2% and 3% rates. Applying vermicompost at 2% w/w through soil amendment was the appropriate rate for promoting the growth and yield of potted vegetable soybeans. The results can be used to guide the application of vermicompost to control soil-borne plant diseases, promote plant growth, and enhance yields, especially in terms of organic crop production. Further research is needed to evaluate its potential for other potted crops and protect against soil-borne diseases. [ABSTRACT FROM AUTHOR]

Aims: Damping-off disease, caused by Fusarium oxysporum, affects the growth of Pinus massoniana seedlings. Plant growth-promoting fungi and rhizobacteria (PGPF and PGPR) are widely used in agriculture to control plant soil-borne disease, however, the joint mechanism by which they inhibit damping-off disease in forestry requires further exploration. Methods: The current study screened for the ability of antagonistic PGPF and PGPR strains to inhibit the pathogen, and used soil microbiome and plant transcriptome technologies to characterize the biocontrol mechanism. Results: PGPF strain 3Y, identified as Trichoderma longibrachiatum, and PGPR strain K29, identified as Burkholderia stabilis, were screened and found to strongly inhibit the growth of F. oxysporum through direct contact with the hyphae. The combined use of T. longibrachiatum and B. stabilis effectively reduced disease incidence and severity, and promoted the growth of P. massoniana seedlings, and enhanced soluble sugar, proline, SOD and POD activities. Compound strains treatment impacted the structure of rhizosphere bacterial microbial community, causing significant differences in the relative abundances of some key phyla and genera, promoting the enrichment of some beneficial microorganisms. Transcriptome profiles showed that combination treatment with the biocontrol strains induced the expressions of 8541 differentially expressed genes (DEGs). These genes participated in key biological pathways associated with starch and sucrose metabolism, plant hormone signal transduction, photosynthesis, antioxidant enzymes, and proline synthesis. Conclusion: The combined use of PGPF and PGPR strains controlled F. oxysporum infection of P. massoniana seedlings by regulating physiological responses and soil microbial community. [ABSTRACT FROM AUTHOR]

This article in the Journal of Fish Diseases examines the effects of the fungicide dimethomorph on various species of oomycetes, which are harmful to plants and animals, including humans. The study specifically focuses on three oomycete species that cause significant economic losses in agriculture and aquaculture. Through in vitro tests and scanning electron microscopy, the researchers found that dimethomorph inhibited the growth of the oomycetes and caused morphological changes in one species. The study suggests that more research is needed to fully understand these pathogens and develop effective treatments. [Extracted from the article]

Continuous cropping has become a common form of agricultural production at present, but with the increase of continuous cropping years, continuous cropping obstacles such as soil-borne diseases and plant growth potential decline are becoming more and more common. At present, the causes of continuous cropping obstacles and continuous cropping restoration have become a hot issue in agricultural research. This paper summarized the effects of continuous cropping obstacles on soil microbial community structure and main technical methods to repair continuous cropping obstacles, such as agricultural measure management, microbial balance adjustment and soil improvement, aiming to provide theoretical reference for protecting the sustainable utilization of soil ecosystem and ensuring the stability of crop production [ABSTRACT FROM AUTHOR]

This document is a corrigendum for an article titled "Active substances of myxobacteria against plant diseases and their action mechanisms." The corrigendum addresses errors in the article, including an incorrect article title and missing citations. The article discusses the active substances produced by myxobacteria and their potential for biological control of plant diseases. It explores the mechanisms of action, including the role of carbohydrate-active enzymes and small molecule compounds. The authors are affiliated with the College of Life Sciences and the College of Science at Inner Mongolia Agricultural University in China. Myxobacteria are microorganisms known for their complex life cycles and unique social behaviors. They have a wide range of habitats, including soil, rotting wood, animal dung, and marine environments. Myxobacteria have become a valuable resource for new natural compounds, with approximately 40% of their metabolites having novel chemical structures. These metabolites play important roles in regulating cell-cell interactions within the colony and in prey hunting. Myxobacteria have great potential in plant disease control due to their ability to produce enzymes and small molecule compounds that can degrade cell walls, inhibit biofilm formation, and interfere with protein synthesis in plant pathogens. [Extracted from the article]

The stability of microbial communities, especially among core taxa, is essential for supporting plant health. However, the impacts of disease infection on the stability of rhizosphere fungal core microbiome remain largely unexplored. In this study, we delved into the effects of root rot infestation on the community structure, function, network complexity, and stability of Sanqi fungal core microbiomes, employing amplicon sequencing combined with co-occurrence network and cohesion analyses. Our investigation revealed that root rot disease led to a decrease in the α-diversity but an increase in the β-diversity of the Sanqi fungal core microbiomes in the rhizosphere. Notably, Ilyonectria, Plectosphaerella, and Fusarium emerged as indicator species in the rhizosphere core microbiome of root rot-infected Sanqi plants, while Mortierella predominated as the dominant biomarker taxa in healthy soils. Additionally, root rot diminished the complexity and modularity of the rhizosphere networks by reducing the metrics associated with nodes, edges, degrees, and modularity. Furthermore, root rot resulted in a reduction in the proportion of negative connections in the network and the negative/positive cohesion of the entire core fungal microbiome. Particularly noteworthy was the observation that root rot infection destabilized the rhizosphere core fungal microbiome by weakening the negative connectivity associated with beneficial agents. Collectively, these results highlight the significance of the negative connectivity of beneficial agents in ensuring the stability of core microbial community. IMPORTANCE Root rot disease has been reported as the most devastating disease in the production process of artificial cultivated Sanqi ginseng, which seriously threatens the Sanqi industry. This study provides valuable insights into how root rot influence s microbial relationships within the community. These findings open up opportunities for disease prevention and the promotion of plant health by regulating microbial interactions. In summary, the research sheds light on the ecological consequences of root rot on rhizosphere fungal microbiomes and offers potential strategies for managing soil-borne diseases and enhancing plant health. [ABSTRACT FROM AUTHOR]

General plant diseases as well as soil‐borne pathogens severely reduce agricultural yield. The rhizosphere (the region of the soil that includes and surrounds the roots) is an important niche for microbial diversity in particular phytobeneficial bacteria including plant growth‐promoting rhizobacteria (PGPR) which have been used for a very long time to combat plant diseases. Pathogen control and crop productivity can both be improved through the use of PGPR several mechanisms, including iron‐based nutrition, antibiotics, volatile substances, enzymes, biofilm, allelochemicals, and so on. Their modes of action and molecular mechanisms have improved our comprehension of how they are used to control crop disease. Therefore, there is a lot of literal information available regarding PGPR, but this review stands out since it starts with the fundamentals: the concept of the rhizosphere and the colonization process of the latter, particularly because it covers the most mechanisms. A broad figure is used to present the study's findings. The advantages of using PGPR as bioinoculants in sustainable agriculture are also mentioned. [ABSTRACT FROM AUTHOR]

The utilization of Trichoderma longibrachiatum filtrate as a safe biocontrol method for producing zinc nanoparticles is a promising approach for managing pests and diseases in agricultural crops. The identification of Trichoderma sp. was achieved through PCR amplification and sequencing of 18s as ON203115, while the synthesis of ZnO-NPs was accomplished by employing Trichoderma filtration. The presence of ZnO-NPs was confirmed by observing a color change to dark green, along with the use of visible and UV spectrophotometers, and the formation and chemical structure of ZnO-NPs were examined. Direct exposure to ZnO-NPs exhibited a significant inhibitory effect on the growth of Fusarium oxysporum at 80.73% compared with control. Also, the percent mortality of Meloidogyne incognita second juveniles stage (J2s) results showed 11.82%, 37.63%, 40.86%, and 89.65% after 6, 12, 24, and 72 h, respectively in vitro. Disease resistance was assessed in the greenhouse against M. incognita and F. oxysporum using the drench application of ZnO-NPs. The application of ZnO-NPs significantly reduced the disease severity of F. oxysporum and improved the quality and quantity of sweet pepper yield. In addition, the application of ZnO-NPs to M. incognita resulted in a significant reduction in the number of nematode galls, egg masses per root, eggs/egg mass, and females by 98%, 99%, 99.9%, and 95.5% respectively. Furthermore, it was observed that the application of ZnO-NPs to pepper plants not only inhibited the growth of F. oxysporum and M. incognita, but also promoted the recovery of pepper plants as indicated by improvements in stem length by 106%, root length 102%, fresh weight 112%, root fresh weight 107%, and leaf area 118% compared to healthy control plants. Additionally, real-time PCR application and DD-PCR technique revealed that the application of ZnO-NPs stimulated the secretion of certain enzymes. These findings suggest that the biosynthesized ZnO-NPs possess anti-nematode and antifungal properties, making them effective for protecting plants against M. incognita and F. oxysporum invasion in soil. This study significantly contributes to our understanding of the nematicidal and fungicidal activities of ZnO-NPs in suppressing soil-borne diseases. [ABSTRACT FROM AUTHOR]

Introduction: Aspergillus nomiae is known as a pathogenic fungus that infects humans and plants but has never been reported as an entomophagous fungus (EPF) that can provide other functions as an endotype. Methods: A strain of EPF was isolated and identified from diseased larvae of Spodoptera litura in a soybean field and designated AnS1Gzl-1. Pathogenicity of the strain toward various insect pests was evaluated, especially the ability to colonize plants and induce resistance against phytopathogens and insect pests. Results: The isolated EPF strain AnS1Gzl-1 was identified as A. nomiae; it showed strong pathogenicity toward five insect pests belonging to Lepidoptera and Hemiptera. Furthermore, the strain inhibited the growth of Sclerotinia sclerotiorum in vitro, a causal agent of soil-borne plant disease. It colonized plants as an endophyte via root irrigation with a high colonization rate of 90%, thereby inducing plant resistance against phytopathogen infection, and disrupting the feeding selectivity of S. litura larvae. Discussion: This is the first record of a natural infection of A. nomiae on insects. A. nomiae has the potential to be used as a dual biocontrol EPF because of its ability to not only kill a broad spectrum of insect pests directly but also induce resistance against phytopathogens via plant colonization. [ABSTRACT FROM AUTHOR]

This study reports on the effects of pretreated biogas slurry on degraded farm soil properties, microflora and the production of Capsicum spp. The responses of soil properties, microorganisms and Capsicum spp. production to biogas slurry pretreated soil were determined. The biogas slurry pretreatment of degraded soil increases the total nitrogen (0.15–0.32 g/kg), total phosphorus (0.13–0.75 g/kg), available phosphorus (102.62–190.68 mg/kg), available potassium (78.94–140.31 mg/kg), organic carbon content (0.67–3.32 g/kg) and pH value of the soil, while the population, diversity and distribution of soil bacteria and fungi were significantly affected. Interestingly, soil ammonium nitrogen, soil pH and soil nitrate nitrogen were highly correlated with the population of bacteria and fungi present in the pretreated soil. The soil with biogas slurry pretreatment of 495 m3/hm2 favored the seedling survival rate, flowering rate and fruit-bearing rate of Capsicum spp. and significantly reduced the rate of rigid seedlings. In this study, the application of 495 m3/hm2 biogas slurry to pretreat degraded soil has achieved the multiple goals of biogas slurry valorization, soil biofertilization and preventing and controlling plant diseases caused by soil-borne pathogenic microorganisms. These findings are of significant importance for the safe and environmentally friendly application of biogas slurry for soil pretreatment. [ABSTRACT FROM AUTHOR]

The rhizobiome is a critical determinant of plant health, generally attributed to diverse bacteria and fungi. However, the contribution of soil-dwelling animals to plant health has been greatly underestimated and deserves further investigation. Nematodes, as co-evolved partners of plants, may be significantly enhancing plant health due to their predominant role as plant allies rather than plant enemies in the rhizosphere. Plant-parasitic nematodes cause root damage that facilitates opportunistic pathogen colonization. However, the damaged root cells also develop a community of beneficial microbiota and attract antagonists that strengthen plant defense responses. While bacterivorous nematodes cannot suppress plant disease directly by consuming bacterial pathogens, they could have a larger impact on plant protection by bringing antagonistic bacteria into contact with plant pathogens, thereby inhibiting pathogen growth. Nematodes are a crucial component of rhizosphere biodiversity, affecting plant health as the most abundant and functionally diverse soil animals. Plant-parasitic nematodes are generally considered harmful, which may overlook their potential benefits to plants when coexisting with free-living nematodes in soil. We provide new insights into nematodes as vital plant partners. Plant root damage by plant-parasitic nematodes creates opportunities for pathogens and beneficial microbiota to colonize the rhizosphere. Free-living nematodes coordinate microbiota to suppress plant diseases, but they are susceptible to mortality from plant pathogens, potentially favoring pathogen release in the root zone. We conclude that the nematode's role in regulating plant pathogens represents a missing link, constraining our ability to predict and control soil-borne diseases in healthy plants. [ABSTRACT FROM AUTHOR]

Chili (Capsicum annuum L.) is highly susceptible to soilborne diseases, thereby presenting a significant threat that results in considerable yield losses in chili production. The exploration of genes conferring resistance and the underlying defense mechanisms presents a promising strategy for bolstering plant disease control. In this study, we selected two distinct cultivars, the disease-sensitive 'Hailan 99' and the disease-tolerant 'Sanxiaqing', to elucidate the molecular basis of their responses to soilborne disease intervention. We conducted a comprehensive analysis of root morphological characteristics and transcriptome profiles under stress conditions. Our findings revealed that, when subjected to soilborne disease intervention, these two cultivars exhibited contrasting root system characteristics and responses, reflecting diverse defense strategies. The disease-resistant cultivar demonstrated superior adaptability, possibly owing to its capacity for swift recognition of pathogen effectors, activation of defense responses, and effective containment of infection at localized sites, thus impeding disease progression. Noteworthy genes such as T459_04053, implicated in effector recognition; MSTRG.26158, MSTRG.30886, and T459_22510, associated with secondary metabolite biosynthesis; and T459_05615, partaking in the autophagy pathway, along with other differentially expressed genes linked to effector recognition, immune activation, and modulation of cell death processes, offer valuable insights into enhancing soilborne disease resistance in chili. Furthermore, these findings contribute to an enhanced understanding of the molecular mechanisms underlying soilborne disease resistance in diverse plant crops. [ABSTRACT FROM AUTHOR]

Plant Prot. 2023; 77: 31-35 16 Yoshida S, Tsushima S (2020) Development of a novel soil-borne disease management strategy, health checkup based soil-borne disease management (HeSoDiM). Our developed soil-borne disease management system, HeSoDiM, is anticipated to contribute to attaining the sustainable use of arable lands by preventing soil-borne diseases, and its dissemination contributes to the promotion of agriculture. An extension worker evaluation found disease management against club root of broccoli based on HeSo + to be successful, and the application was a useful tool for farmers to discuss and adopting disease management strategies. [Extracted from the article]

The soil microbiome is known to be crucial for the control of soil-borne plant diseases. However, there is still little knowledge on how to modify the soil microbiome to induce or increase disease suppressiveness. In the present study, we applied eleven soil health treatments combined with conventional and organic agricultural management in a long-term field experiment. Suppressiveness against Pythium ultimum and Rhizoctonia solani was assessed in bioassays for 2 years. In addition, the microbiome community composition and microbial abundance were determined. We found that while several treatments changed the microbial community composition compared to the control, only a combination treatment of anaerobic soil disinfestation, hair meal, and compost addition resulted in suppressiveness against P. ultimum. Pythium suppressiveness is likely to have been caused by an increased microbial abundance and activity. Moreover, the increased abundance of several bacterial taxa, such as Pseudomonas sp., Chryseobacterium sp., members of the family Chitinophagaceae, and the fungal genus Mortierella sp. and family Trichosporonaceae, was measured. There was no overall difference in suppressiveness between conventional and organic land management. Also, no suppressiveness against R. solani could be detected. Our results indicate that a treatment combining the reduction of microorganisms followed by a recovery phase with high amounts of organic amendments may be more effective in inducing suppressiveness than treatments consisting of only one of these measures. [ABSTRACT FROM AUTHOR]

Plant diseases caused by soilborne pathogens are a major limiting factor in crop production. Bacterial wilt disease, caused by soilborne bacteria in the Ralstonia solanacearum Species Complex (Ralstonia), results in significant crop loss throughout the world. Ralstonia invades root systems and colonizes plant xylem, changing plant physiology and ultimately causing plant wilting in susceptible varieties. Elucidating how Ralstonia invades and colonizes plants is central to developing strategies for crop protection. Here we review Ralstonia pathogenesis from root detection and attachment, early root colonization, xylem invasion and subsequent wilting. We focus primarily on studies in tomato from the last 5–10 years. Recent work has identified elegant mechanisms Ralstonia uses to adapt to the plant xylem, and has discovered new genes that function in Ralstonia fitness in planta. A picture is emerging of an amazingly versatile pathogen that uses multiple strategies to make its surrounding environment more hospitable and can adapt to new environments. [ABSTRACT FROM AUTHOR]

Wheat sharp eyespot, a stem disease caused by the soilborne fungus Rhizoctonia cerealis van der Hoeven, has become a threat to wheat production worldwide. Exploiting resistance resources from wild relatives of wheat is a promising strategy for controlling this disease. In this study, a new wheat-Dasypyrum villosum T2DS.2V#4L translocation line in the background of Chinese Spring (CS) showed stable resistance to R. cerealis. Introgression of the T2DS.2V#4L chromosome into wheat cultivar Aikang 58 by backcrossing produced a marked increase in sharp eyespot resistance in NIL-T2DS.2V#4L in comparison with NILT2DS .2DL, and no detrimental effects of 2V#4L on agronomic traits were observed in the BC2F2, BC2F2:3, and BC2F2:4 generations. Flow-sorted sequencing of 2V#4L yielded 384.3 Mb of assembled sequence, and 8836 genes were predicted of which 6154 had orthologs in at least one of the 2AL, 2BL, and 2DL arms of CS, whereas 1549 genes were unique to 2V#4L. About 100,000 SNPs were detected in genes of 2V#4L and 2DL in 10 sequenced bread wheat cultivars. A Kompetitive Allele Specific Polymerase chain reaction and 30 conserved ortholog sequence markers were developed to trace the 2V#4L chromatin in wheat backgrounds. T2DS.2V#4L compensating translocation lines represent novel germplasm with sharp eyespot resistance and the markers will allow rapid detection in breeding programs. [ABSTRACT FROM AUTHOR]

This document is an editorial published in the journal Frontiers in Plant Science. It discusses the topic of plant resistance to soil-borne diseases, which continue to pose challenges to global agriculture. The editorial highlights the genetic basis of plant resistance and effective strategies for managing these diseases. The document categorizes the research articles included in the topic into three themes: pathogenesis of soil-borne diseases, identification of key genes involved in plant resistance, and biological control of these diseases. The editorial provides insights into autotoxins in plants, tobacco target spot disease, basal stalk rot disease in sunflowers, brown stem rot disease in soybeans, Phytophthora-associated diseases, and charcoal rot disease. It also mentions the importance of understanding the mechanisms of soil-borne disease resistance for developing disease control technologies. [Extracted from the article]

Background: Allyl isothiocyanate (AITC) is a natural product with high volatility that is used as a biofumigant to alleviate soil-borne plant diseases, and problems such as root knot nematodes (RKNs) that necessitate continuous cropping. However, little research has assessed the effects of AITC fumigation on medicinal plants. Results: AITC significantly reduced the population of RKNs in soil (p < 0.0001) and showed an excellent RKN disease control effect within 6 months after sowing Panax notoginseng (p < 0.0001). The seedling survival rate of 2-year-old P. notoginseng was approximately 1.7-fold higher after soil treatment with AITC (p = 0.1008). 16S rRNA sequencing indicated that the AITC treatment affected bacterial richness rather than diversity in consecutively cultivated (CC) soil. Furthermore, biomarkers with statistical differences between AITC-treated and untreated CC soil showed that Pirellulales (order), Pirellulaceae (family), Pseudomonadaceae (family), and Pseudomonas (genus) played important roles in the AITC-treated group. In addition, the microbiome functional phenotypes predicted using the BugBase tool suggested that AITC treatment is more conducive to improving CC soil through changes in the bacterial community structure. Crucially, our research also suggested that AITC soil treatment significantly increases soil organic matter (p = 0.0055), total nitrogen (p = 0.0054), and available potassium (p = 0.0373), which promotes the survival of a succeeding medicinal plant (Polygonatum kingianum). Conclusion: AITC is an ecologically friendly soil treatment that affects the top 10 bacterial richness but not diversity. It could also provide a basis for a useful agricultural soil management measure to alleviate soil sickness. [ABSTRACT FROM AUTHOR]

Global population is increasing massively and so is the demand for food. To meet the requirements, crops are being grown and harvested by using modern technologies. Also, food crops are at risk of some abiotic and biotic factors mainly pathogens (soil or airborne). To boost the production of food crops and to reduce the damage caused by biotic factors the farmer community increases the use of chemical fertilizers, insecticides, and pesticides. However, these are effective to overcome the problems but also make the pathogens resistant, affecting food quality and polluting the environment. To minimize the pathogenic attack and enhance the crop yield there is a need of adapting an ecofriendly way. Soil organic amendments are the best preventive practice for the suppression of soil-borne pathogens. Improving the soil’s physical, chemical, and microbial characteristics. Some organic amendments enhance the soil particles, increase pore size, and decrease soil bulk density which influences a positive effect on soil aeration and structure. Different types of organic amendments such as biochar, animal manure, green manure, and compost are reported to be effective against diseases caused by different pathogens and enhance plant nutrient uptake ability, and improve soil health. This current review focuses on the use of different soil organic amendments and their capability for suppressing plant disease caused by soil-borne pathogens in a natural and eco-friendly manner. [ABSTRACT FROM AUTHOR]

Introduction: Root-knot nematode (RKN; Meloidogyne spp.) is one of the most infamous soilborne plant diseases, causing severe crop losses every year. Effector proteins secreted by RKNs play crucial roles during plant-nematode interaction. However, less is known about whether RKN effector proteins can impact the rhizosphere microbial environment. Methods: In this study, we investigated the rhizosphere microbiome community of MiMIF-2 (a plant immunity-modulating effector) transgenic Arabidopsis thaliana with or without nematode infection using the Illumina high-throughput sequencing analysis. Results and discussion: The results showed that the bacterial species richness index increased, while the fungi species richness index decreased in M. incognita-infected MiMIF-2 transgenic A. thaliana plants. The relative abundance of genera such as Clitopilus, Komagataeibacter, Lactobacillus, Prevotella, Moritella, Vibrio, Escherichia-Shigella, and Pseudomonas was reduced in MiMIF-2 transgenic A. thaliana plants compared to wild type, but was significantly increased after inoculation with M. incognita. The Cluster of Orthologous Genes (COG) function classification analysis revealed a decrease in the relative abundance of defense mechanisms, secondary metabolite biosynthesis, transport, and nematode infection catabolism-related functions in MiMIF-2 lines compared to the wild type. These differences may be the reason for the increased susceptibility of MiMIF-2 transgenic A. thaliana to nematode infection. Our results provide a new insight into RKN effector proteins and their association with the microbial community, host, and plant pathogens, which will lead to the exploration of new innovative ideas for future biological control of RKNs. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Erciyes Agriculture & Animal Science is the property of Erciyes Tarim ve Hayvan Bilimleri Dergisi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Soil-borne plant diseases seriously threaten the tomato industry worldwide. Currently, eco-friendly biocontrol strategies have been increasingly considered as effective approaches to control the incidence of disease. In this study, we identified bacteria that could be used as biocontrol agents to mitigate the growth and spread of the pathogens causing economically significant diseases of tomato plants, such as tomato bacterial wilt and tomato Fusarium wilt. Specifically, we isolated a strain of Bacillus velezensis (RC116) from tomato rhizosphere soil in Guangdong Province, China, with high biocontrol potential and confirmed its identity using both morphological and molecular approaches. RC116 not only produced protease, amylase, lipase, and siderophores but also secreted indoleacetic acid, and dissolved organophosphorus in vivo. Moreover, 12 Bacillus biocontrol maker genes associated with antibiotics biosynthesis could be amplified in the RC116 genome. Extracellular secreted proteins of RC116 also exhibited strong lytic activity against Ralstonia solanacearum and Fusarium oxysporum f. sp. Lycopersici. Pot experiments showed that the biocontrol efficacy of RC116 against tomato bacteria wilt was 81%, and consequently, RC116 significantly promoted the growth of tomato plantlets. Based on these multiple biocontrol traits, RC116 is expected to be developed into a broad-spectrum biocontrol agent. Although several previous studies have examined the utility of B. velezensis for the control of fungal diseases, few studies to date have evaluated the utility of B. velezensis for the control of bacterial diseases. Our study fills this research gap. Collectively, our findings provide new insights that will aid the control of soil-borne diseases, as well as future studies of B. velezensis strains. [ABSTRACT FROM AUTHOR]

The cliff rose (Armeria maritima), like other halophytes, has a phenolics-based antioxidant system that allows it to grow in saline habitats. Provided that antioxidant properties are usually accompanied by antimicrobial activity, in this study we investigated the phytochemicals present in a hydromethanolic extract of A. maritima flowers and explored its antifungal potential. The main phytocompounds, identified by gas chromatography–mass spectrometry, were: hexadecanoic acid, octadecanoic acid, 9-octadecenoic acid, 3-(3,4-dihydroxy-phenyl)-acrylic acid ethyl ester, and benzeneacetaldehyde. The antifungal activity of the extract and its main constituents—alone and in combination with chitosan oligomers—was tested against six pathogenic taxa associated with soil-borne diseases of plant hosts in the family Cucurbitaceae: Fusarium equiseti, F. oxysporum f. sp. niveum, Macrophomina phaseolina, Neocosmospora falciformis, N. keratoplastica, and Sclerotinia sclerotiorum. In in vitro tests, EC90 effective concentrations in the 166−865 μg·mL−1 range were obtained for the chitosan oligomers–A. maritima extract conjugate complexes, lower than those obtained for fosetyl-Al and azoxystrobin synthetic fungicides tested for comparison purposes, and even outperforming mancozeb against F. equiseti. In ex situ tests against S. sclerotiorum conducted on artificially inoculated cucumber slices, full protection was achieved at a dose of 250 μg·mL−1. Thus, the reported results support the valorization of A. maritima as a source of biorationals for Cucurbitaceae pathogens protection, suitable for both organic and conventional agriculture. [ABSTRACT FROM AUTHOR]

Simple Summary: Verticillium dahliae (Vd) is a kind of soil-borne filamentous fungus that can cause Verticillium wilt in many crops and serious damage to agricultural production. Vd 991 is a main pathogen of cotton Verticillium wilt. Previously, we isolated C17 mycosubtilin from Bacillus subtilis J15 (BS J15) broth and showed a significant inhibitory effect on cotton Verticillium wilt. However, the specific fungistatic mechanism by which C17 mycosubtilin antagonizes Vd 991 is not clear. Here, we found that C17 mycosubtilin inhibited the growth and spore germination of Vd 991. C17 mycosubtilin treatment caused shrinking, sinking, and even damage to spores, resulting in rough deformation and uneven distribution of hyphal contents, damage to the cell membrane and cell wall, and mitochondrial swelling of fungi. Moreover, C17 mycosubtilin induced necrosis of Vd 991 in a time-dependent manner. Differential transcription analysis showed that C17 mycosubtilin inhibited fungal growth mainly by destroying the cell structure, blocking the cell cycle, disturbing substance, energy metabolism, and so on. Our results reveal the potential mechanism by which C17 mycosubtilin antagonizes Vd 991, providing useful information for development of more effective antimicrobials. Verticillium wilt is a kind of soil-borne plant fungal disease caused by Verticillium dahliae (Vd). Vd 991 is a strong pathogen causing cotton Verticillium wilt. Previously, we isolated a compound from the secondary metabolites of Bacillus subtilis J15 (BS J15), which showed a significant control effect on cotton Verticillium wilt and was identified as C17 mycosubtilin. However, the specific fungistatic mechanism by which C17 mycosubtilin antagonizes Vd 991 is not clear. Here, we first showed that C17 mycosubtilin inhibits the growth of Vd 991 and affects germination of spores at the minimum inhibitory concentration (MIC). Morphological observation showed that C17 mycosubtilin treatment caused shrinking, sinking, and even damage to spores; the hyphae became twisted and rough, the surface was sunken, and the contents were unevenly distributed, resulting in thinning and damage to the cell membrane and cell wall and swelling of mitochondria of fungi. Flow cytometry analysis with ANNEXINV-FITC/PI staining showed that C17 mycosubtilin induces necrosis of Vd 991 cells in a time-dependent manner. Differential transcription analysis showed that C17 mycosubtilin at a semi-inhibitory concentration (IC50) treated Vd 991 for 2 and 6 h and inhibited fungal growth mainly by destroying synthesis of the fungal cell membrane and cell wall, inhibiting its DNA replication and transcriptional translation process, blocking its cell cycle, destroying fungal energy and substance metabolism, and disrupting the redox process of fungi. These results directly showed the mechanism by which C17 mycosubtilin antagonizes Vd 991, providing clues for the mechanism of action of lipopeptides and useful information for development of more effective antimicrobials. [ABSTRACT FROM AUTHOR]

Purpose: Brassica seed meals (BSMs) are widely used as biofumigants to control various soil-borne plant diseases. However, the mechanism of bacterial community reconstruction following fumigation with BSMs remains poorly understood. Methods: In the present study, to decipher the mechanism of bacterial community reconstruction in fumigated soil and to understand the effect of bacterial communities in fumigated soil on rhizosphere recruitment and subsequent disease control, we investigated the bulk soil and rhizosphere bacterial communities using field experiments in soils treated with various fumigants (Brassica campestris seed meal, Brassica juncea seed meal, and the chemical fumigant dazomet) in two greenhouses subsequently used to grow tomato and cantaloupe, respectively. Results: This study revealed that bulk soil bacterial community composition changed significantly after fumigation extinction and recovery. Firmicutes and Proteobacteria, showing high resistance and resilience in the extinction and recovery processes, respectively, represented the key microorganisms for community reconstruction and rhizosphere recruitment. Moreover, nutrients supplied by BSMs, especially available phosphorus (AP), in fumigated soils determined the post-restoration changes in bacterial community composition. Additionally, BSMs showed greater potential than chemical fumigant dazomet in rebuilding beneficial bacterial communities and controlling potential soil pathogens by enriching gram-positive phyla Firmicutes and Actinobacteria and their respective affiliated genera Bacillus and Streptomyces. Conclusion: These results provide a fundamental ecological understanding of the response of soil-inhabiting microbes to fumigation and the reconstruction of soil beneficial bacterial communities after BSM fumigation. Thus, this study improves the understanding of the effects of biofumigants on soil-borne plant disease control in agriculture. [ABSTRACT FROM AUTHOR]

Bacillus subtilis strain NCD-2 is a promising biocontrol agent for soil-borne plant diseases and shows potential for promoting the growth of some crops. The purposes of this study were to analyze the colonization ability of strain NCD-2 in different crops and reveal the plant growth promotion mechanism of strain NCD-2 by rhizosphere microbiome analysis. qRT-PCR was used to determine the populations of strain NCD-2, and microbial communities' structures were analyzed through amplicon sequencing after application of strain NCD-2. Results demonstrated that strain NCD-2 had a good growth promotion effect on tomato, eggplant and pepper, and it was the most abundant in eggplant rhizosphere soil. There were significantly differences in the types of beneficial microorganisms recruited for different crops after application of strain NCD-2. PICRUSt analysis showed that the relative abundances of functional genes for amino acid transport and metabolism, coenzyme transport and metabolism, lipid transport and metabolism, inorganic ion transport and metabolism, and defense mechanisms were enriched in the rhizospheres of pepper and eggplant more than in the rhizospheres of cotton, tomato and maize after application of strain NCD-2. In summary, the colonization ability of strain NCD-2 for five plants was different. There were differences in microbial communities' structure in rhizosphere of different plants after application of strain NCD-2. Based on the results obtained in this study, it was concluded that the growth promoting ability of strain NCD-2 were correlated with its colonization quantity and the microbial species it recruited. [ABSTRACT FROM AUTHOR]

Microbial seed coatings serve as effective, labor-saving, and ecofriendly means of controlling soil-borne plant diseases. However, the survival of microbial agents on seed surfaces and in the rhizosphere remains a crucial challenge. In this work, we embedded a biocontrol bacteria (Bacillus subtilis ZF71) in sodium alginate (SA)/pectin (PC) hydrogel as a seed coating agent to control Fusarium root rot in cucumber. The formula of SA/PC hydrogel was optimized with the highest coating uniformity of 90 % in cucumber seeds. SA/PC hydrogel was characterized using rheological, gel content, and water content tests, thermal gravimetric analysis, and Fourier transform infrared spectroscopy. Bacillus subtilis ZF71 within the SA/PC hydrogel network formed a biofilm-like structure with a high viable cell content (8.30 log CFU/seed). After 37 days of storage, there was still a high number of Bacillus subtilis ZF71 cells (7.23 log CFU/seed) surviving on the surface of cucumber seeds. Pot experiments revealed a higher control efficiency against Fusarium root rot in ZF71-SA/PC cucumber seeds (53.26 %) compared with roots irrigated with a ZF71 suspension. Overall, this study introduced a promising microbial seed coating strategy based on biofilm formation that improved performance against soil-borne plant diseases. [ABSTRACT FROM AUTHOR]

• Bacillus velezensis GX1 represents a promising biocontrol agent against lily bulb rot. • Crude extracts of lipopeptides from the GX1 fermentation broth inhibited Fusarium commune. • GX1 has the potential to synthesize four antimicrobial peptides (AMPs). Bulb rot of lily (Lilium brownii var. viridulum), caused by Fusarium commune, is a serious soilborne disease of lily plants. In this study, several bacterial isolates were obtained from the rhizosphere of healthy lily plants and evaluated for biocontrol potential. Among the obtained isolates, GX1 had the highest level of antifungal activity in vitro, inhibiting the growth of F. commune by 52.0 %, relative to the control (CK). The isolate was identified as Bacillus velezensis based on its morphology and 16S rRNA and gyrB gene sequence analysis. The fermentation broth of GX1 after 12 d of fermentation at 25 °C (pH 7) exhibited strong antifungal activity. A crude lipopeptide extracts of GX1 fermentation broth was as effective (50.3 %) at inhibiting the mycelial growth of F. commune as living cultures of GX1. GX1 possesses fenD, bmyB, srfAA and bacA antimicrobial peptide (AMP) genes, which may be the primary source of its antifungal activity. GX1 significantly reduced the disease severity index of lily bulb rot in pot experiments, indicating that B. velezensis GX1 has substantial potential for the biological control of lily bulb rot. [ABSTRACT FROM AUTHOR]

Soil-borne plant diseases significantly threaten agricultural sustainability, leading to substantial crop loss. Although chemical pesticides are effective, their environmental and health risks are concerning. Recently, compost has gained attention as a sustainable alternative for managing plant pathogens. Its effectiveness is due to its physical (e.g., particle aggregation and moisture retention), chemical (e.g., pH, electrical conductivity, nutrient balance, and humic substances), and biological properties (e.g., diverse microbial communities). These properties contribute to pathogen suppression through direct mechanisms, involving the release of toxic compounds and competition with compost-introduced microbiota, and indirect mechanisms, including the modulation of plant biochemical pathways, alleviation of oxidative damage, enhancement of defense-related enzymatic activities, and induction of systemic resistance. Overall, this review groups and classify the mechanisms induced by compost, highlighting its potential as a natural substitute to chemical pesticides. [Display omitted] • Compost outperforms chemical pesticides in controlling pathogens and promoting plant health. • Compost with specific traits creates an unfavorable environment for plant pathogens. • Compost modulates plant physiological process to combat pathogens. • Compost restores plant homeostasis and improves plant growth and development. [ABSTRACT FROM AUTHOR]

Accurately predicting soil-borne fungal diseases linked to plant diseases through the analysis of soil microbial communities is advantageous for early disease detection and monitoring. In this study, a meta-analysis was conducted to establish a classification model for two soil-borne plant fungal diseases, Fusarium and Verticillium wilt disease, based on soil microbiome datasets. The study integrated a scalable denoising method and an imbalanced data processing strategy for processing imbalanced data. The findings reveal a substantial enhancement in model performance when employing denoised and balanced datasets as opposed to the original dataset. Overall, the model based on bacterial ASV features outperformed the model based on fungal ASV features, achieving an accuracy of over 90 % in predicting Fusarium and Verticillium wilt disease on the independent test set. Some bacteria, such as those classified as the Chitinophagaceae , Nocardioides , and Sphingomonas , have been identified as biomarkers for distinguishing between healthy and diseased soils. Despite this achievement, the models exhibited suboptimal classification precision, underscoring the necessity for additional training sets or more comprehensive environmental information to augment disease prediction capabilities. Our analysis highlights the importance of microbiome-based deep learning (DL) models to make plant disease predictions based on microbiome characteristics. [ABSTRACT FROM AUTHOR]

The use of wood-derived materials in soilless substrates for horticultural crop production is increasing; however, there is little information about the effects of wood on the incidence and severity of soilborne diseases of container-grown plants. The objectives of this research were to compare three differently processed wood substrate components blended with sphagnum peat and to investigate the effect of the peat:wood blend ratio on damping-off disease caused by Rhizoctonia solani using radish as a model system. In objective one, raw sphagnum peat was blended with three types of processed pine wood, screw-extruded, twin disc-refined, and hammer-milled, at a volumetric ratio of 70:30 and compared to a 70:30 peat:perlite mix. Radish plants grown in the hammer-milled wood and disc-refined wood had significantly lower damping-off disease severity compared to plants grown in the peat–perlite control. In objective two, sphagnum peat was blended with the three types of processed wood at a volumetric ratio of 90:10, 80:20, and 70:30 and compared to a 70:30 peat–perlite mix. The effect of the blend ratio varied by wood processing type. Higher percentages of Forest Gold and pine tree substrate resulted in lower disease severity. In both objectives, radish plants grown in any of the substrate treatments containing wood infested with R. solani tended to have lower disease severity compared to plants in the control. Results of this study indicate that the blending of processed pine wood-derived components into peat may enhance the natural suppression of damping-off disease of radish. Further research is needed to elucidate the mode of action of wood-derived materials on disease suppression in container-grown crops and to study the effects for other plant pathogens and crop species. [ABSTRACT FROM AUTHOR]

Aims: The use of rootstock is effective at protecting plants from soil-borne diseases, however, the underlying mechanisms remain to be elucidated. Methods: In this study, the root-associated microbiomes and root exudate profiles of rootstock (grafted) and self-rooted (ungrafted) watermelon plants grown in plastic shelters heavily infected with Fusarium oxysporum f. sp. niveum (FON) were characterized. Results: We showed that grafting markedly controlled Fusarium wilt disease, greatly reduced FON abundance in the rhizoplane and endosphere, and improved microbial diversity across rhizosphere to endosphere in continuous cropping soils. We further found that grafting significantly changed the composition of root-associated microbiomes, improved microbial association network complexity, and had potential beneficial bacterial taxa like Streptomycetales and Sphingomonadales, and fungal taxa like Capnodiales and Sebacinales significantly enriched in grafted watermelon. The grafted watermelon also possessed a distinct root exudate profile from the ungrafted watermelon and rootstock plants, with organic acids (potential autotoxins) significantly depleted but more plant defense-related metabolites such as organosulfur compounds and benzenoids enriched in comparison to ungrafted watermelon. Conclusion: Together, our results suggest that grafting facilitates plant disease resistance potentially by direct antagonism effect through root exudates and indirectly by shaping the protective root-associated microbiomes. [ABSTRACT FROM AUTHOR]

Background: Anaerobic soil disinfestation (ASD) has been proven to be an effective and environmentally friendly method for controlling soil-borne plant diseases. Mechanisms of ASD-mediated pathogen suppression are not fully elucidated but appear to depend on the carbon (C) sources used and involve a combination of abiotic and biotic factors. This study sought to assess the impacts of ASD with different C sources on soil chemical properties, microbial activity, and antagonistic compounds, and identify the major factor(s) driving suppression of tomato bacterial wilt caused by Ralstonia solanacearum. Methods: A pot experiment was conducted containing five treatments, i.e., untreated control (CK), anaerobic treatment without C source (ASD-CK), anaerobic treatment with rice bran (ASD-R), wheat bran (ASD-W) and peanut bran (ASD-P). Results: All the ASD treatments significantly reduced disease incidence by 83–100% and simultaneously promoted tomato growth, while anaerobic treatments with C sources achieved a better effect than anaerobic treatment alone. This could be associated with the improved soil chemical (lowered Eh, NO3−, SO42− and elevated pH) and biological (elevated dehydrogenase and urease activities) properties and elevated production of antagonistic compounds (Fe2+, Mn2+, citric acid, succinic acid, and ammonia) by anaerobic treatments with C sources. Redundancy analysis further indicated that the elevated ammonia (11.1%, P = 0.002), Mn2+ (5.3%, P = 0.002), citric acid (1.8%, P = 0.046) and urease activity (1.0%, P = 0.036) were the major factors driving disease suppression, which all achieved the highest value in ASD-P. Conclusions: In summary, the incorporation of organic materials that improve antagonistic compounds (especially ammonia) production could induce higher inhibition effect against tomato bacterial wilt during the ASD process. [ABSTRACT FROM AUTHOR]

Pseudomonas fluorescens 2P24 is a beneficial plant root-associated microorganism capable of suppressing several soilborne plant diseases. The capacity of P. fluorescens to aggressively colonize the rhizosphere is an important requirement for its biocontrol trait. We previously found that the PcoI/PcoR quorum-sensing system (QS) is involved in regulating the rhizosphere colonization of P. fluorescens. Here, we revealed a sophisticated regulatory network that connects PcoR, RsaL, and MvaT proteins to fine-tune the PcoI/PcoR QS system. Our data showed that PcoR could directly bind to the promoter region of pcoI thereby inducing the PcoI/PcoR QS system, whereas RsaL binds simultaneously with PcoR to the promoter region of pcoI and represses the PcoR-dependent activation of pcoI gene. In addition, RsaL indirectly downregulates the expression of pcoR. Furthermore, we showed that disruption of mvaT enhanced the expression of pcoI, pcoR, and rsaL, whereas MvaT controls the PcoI/PcoR QS in a RsaL-independent manner. Overall, this study elucidates that PcoR, RsaL, and MvaT regulate the PcoI/PcoR QS through a multi-tiered regulatory mechanism and that PcoR is necessary in the RsaL- and MvaT-mediated repression on the expression of pcoI. [ABSTRACT FROM AUTHOR]