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Introduction: Food security and waste management represent the main challenges that need to be addressed in the near future. The use of bioformulations and bioactive compounds obtained from agricultural wastes could represent some of the solutions for the management of soil-borne pathogens. Methods: In the present study, Aureobasidium pullulans strain AP1, tested in oil dispersion (OD) formulation prototype and bio-extracts [hot water extract (HWE) and warm water extract (WWE)] derived from spent mushroom substrate (SMS) of Agaricus bisporus , was tested as sustainable strategies to manage Rhizoctonia solani of lettuce. Results: By in vitro assays, AP1OD at 600 mg L−1 displayed an inhibition by 57% of pathogen mycelial growth, and the SMS extract WWE (40°C) showed a growth stimulation of lettuce seedling by 27%. By In vivo assays, AP1OD formulation used against R. solani reduced by 66.6% the soil-borne pathogen incidence on lettuce plants, and both bio-extracts significantly stimulated lettuce leaves and roots growth (>200%). AP1OD formulation and HWE treatments increased the lettuce genes expression levels (ggps and hppd pdx1) mainly imputed to plant antioxidant potential, vitamin E, and vitamin B6 biosynthesis. Discussion: The present study reported the potential of a new formulation and two bio-extracts, derived from an agricultural waste, to use against R. solani of lettuce, respectively, with antifungal and biostimulant properties. [ABSTRACT FROM AUTHOR]

Bacillus subtilis XF‐1 is a well‐investigated biocontrol agent against the biotrophic Plasmodiophora brassicae Woron., the causal agent of clubroot disease of cruciferous crops. The present study demonstrates that XF‐1 could efficiently control clubroot disease via leaf spraying and provides an understanding of the biocontrol mechanisms. High‐performance thin‐layer chromatography (HTPLC) analysis indicated the presence of fengycin‐type cyclopeptides in the supernatant. A ppsB deletion mutant of XF‐1 resulted in no fengycin production, significantly reduced the lysis rate of testing spores in vitro and the primary infection rate of root hair in vivo, and decreased the protection value against clubroot disease under the greenhouse conditions. Confocal laser scanning microscopy proved that fengycin was not required for leaf internalization and root colonization. Moreover, the expression level of the ppsB gene in XF‐1 was regulated by its cell density in root during interaction with P. brassicae. In addition, the ΔppsB mutant of XF‐1 could not efficiently control disease because it led to a lower activation level of the jasmonic acid and salicylic acid signaling pathways in roots, which are necessary for the plant defense reaction upon pathogen invasion. Altogether, the present study provides a new understanding of specific cues in the interaction between B. subtilis and P. brassicae as well as insights into the application of B. subtilis in agriculture. [ABSTRACT FROM AUTHOR]

【Objective】The study was carried out to explore the distribution patterns of rhizospheric microbial communities in different resistant pepper varieties, aiming to provide a basis for the targeted optimization of rhizospheric microbial community structure of pepper.【Method】Taking the susceptible pepper variety 'Hailan 99' (HL99) and the resistant variety 'Sanxiaqing' (SSQ) as experimental materials, high-throughput sequencing technology was employed to analyze and compare the effects of susceptible and non-susceptible soil environments on the community diversity, species composition, correlation networks and function of bacteria and fungi in the rhizosphere soil of different disease-resistant pepper plants.【Result】Through high-throughput sequencing, a total of 66 617 operational taxonomic units (OTUs) from soil bacterial samples were obtained, among which the dominant phyla were Proteobacteria and Bacteroidetes, with the relative abundances of approximately 40.1% and 15.3%, respectively. From soil fungal samples, 2 948 OTUs were obtained, among which the dominant phylum was Ascomycota, with an average relative abundance of approximately 47.8%. The rhizospheric microbial community structure and species composition of pepper varieties showed significant differences under different soil conditions. Under susceptible soil conditions, the diversity of bacterial communities in pepper rhizosphere decreased, while the diversity of fungal communities increased. The bacterial OTUs decreased by 6.5%-7.8%, and fungal OTUs increased by 8.8%-9.8%. The relative abundance of Fusarium fungi was significantly higher in the susceptible group (5.0%) compared with that in the resistant group (4.8%), while the relative abundance of beneficial fungi like Mortierella and Trichoderma and beneficial bacteria like Pseudomonas and Bacillus was significantly lower in the susceptible group than that in the resistant group. Overall, under the susceptible soil conditions, the abundance of beneficial rhizosphere fungi and bacteria in the resistant group was higher than that in the susceptible group, contributing to a better soil micro-ecological environment. Based on species abundance tables, the correlation relationships of fungi-fungi, fungi-bacteria and bacteria-bacteria species were calculated respectively at the genus level. The results indicated that the rhizosphere microorganisms of pepper formed a complex ecological network, with high co-occurrence between fungi-fungi and fungi-bacteria (with a positive correlation percentage higher than 50%), suggesting that cooperative relationships outweighed competitive ones. The bacteria-bacteria network structure was more complex, with a positive correlation percentage of about 49.9%.【Conclusion】The rhizospheric microbial community structures of different resistant varieties exhibit significant differences under different soil conditions. The interaction of rhizosphere microorganisms forms a complex microbial ecological network structure. The relative abundance of beneficial fungi and bacteria is higher in the resistant variety than that in the susceptible variety, which suppresses more pathogenic microbes, leading to a healthier soil micro-ecological environment. The key groups identified in this study, including Fusarium, Verticillium, Trichoderma, Bacillus and Pseudomonas, will provide important information for the targeted optimization of rhizospheric microbial community structures and offer crucial theoretical references for the biological control of soil-borne diseases.

Abstract Modern intensive cropping systems often contribute to the accumulation of phenolic acids in the soil, which promotes the development of soilborne diseases. This can be suppressed by intercropping. This study analyzed the effects of intercropping on Fusarium wilt based on its effect on photosynthesis under stress by the combination of Fusarium commune and cinnamic acid. The control was not inoculated with F. commune, while the faba bean plants (Vicia faba L.) were inoculated with this pathogen in the other treatments. The infected plants were also treated with cinnamic acid. This study examined the development of Fusarium wilt together with its effects on the leaves, absorption of nutrients, chlorophyll fluorescence parameters, contents of photosynthetic pigments, activities of photosynthetic enzymes, gas exchange parameters, and the photosynthetic assimilates of faba bean from monocropping and intercropping systems. Under monocropping conditions, the leaves of the plants inoculated with F. commune grew significantly less, and there was enhanced occurrence of the Fusarium wilt compared with the control. Compared with the plants solely inoculated with F. commune, the exogenous addition of cinnamic acid to the infected plants significantly further reduced the growth of faba bean leaves and increased the occurrence of Fusarium wilt. A comparison of the combination of F. commune and cinnamic acid in intercropped wheat and faba bean compared with monocropping showed that intercropping improved the absorption of nutrients, increased photosynthetic pigments and its contents, electron transport, photosynthetic enzymes, and photosynthetic assimilates. The combination of these factors reduced the occurrence of Fusarium wilt in faba bean and increased the growth of its leaves. These results showed that intercropping improved the photosynthesis, which promoted the growth of faba bean, thus, reducing the development of Fusarium wilt following the stress of infection by F. commune and cinnamic acid. This research should provide more information to enhance sustainable agriculture.

Modern intensive cropping systems often contribute to the accumulation of phenolic acids in the soil, which promotes the development of soilborne diseases. This can be suppressed by intercropping. This study analyzed the effects of intercropping on Fusarium wilt based on its effect on photosynthesis under stress by the combination of Fusarium commune and cinnamic acid. The control was not inoculated with F. commune, while the faba bean plants (Vicia faba L.) were inoculated with this pathogen in the other treatments. The infected plants were also treated with cinnamic acid. This study examined the development of Fusarium wilt together with its effects on the leaves, absorption of nutrients, chlorophyll fluorescence parameters, contents of photosynthetic pigments, activities of photosynthetic enzymes, gas exchange parameters, and the photosynthetic assimilates of faba bean from monocropping and intercropping systems. Under monocropping conditions, the leaves of the plants inoculated with F. commune grew significantly less, and there was enhanced occurrence of the Fusarium wilt compared with the control. Compared with the plants solely inoculated with F. commune, the exogenous addition of cinnamic acid to the infected plants significantly further reduced the growth of faba bean leaves and increased the occurrence of Fusarium wilt. A comparison of the combination of F. commune and cinnamic acid in intercropped wheat and faba bean compared with monocropping showed that intercropping improved the absorption of nutrients, increased photosynthetic pigments and its contents, electron transport, photosynthetic enzymes, and photosynthetic assimilates. The combination of these factors reduced the occurrence of Fusarium wilt in faba bean and increased the growth of its leaves. These results showed that intercropping improved the photosynthesis, which promoted the growth of faba bean, thus, reducing the development of Fusarium wilt following the stress of infection by F. commune and cinnamic acid. This research should provide more information to enhance sustainable agriculture. [ABSTRACT FROM AUTHOR]

【Objective】The study was carried out to explore the distribution patterns of rhizospheric microbial communities in different resistant pepper varieties, aiming to provide a basis for the targeted optimization of rhizospheric microbial community structure of pepper.【Method】Taking the susceptible pepper variety ‘Hailan 99’ (HL99) and the resistant variety ‘Sanxiaqing’ (SSQ) as experimental materials, high-throughput sequencing technology was employed to analyze and compare the effects of susceptible and non-susceptible soil environments on the community diversity, species composition, correlation networks and function of bacteria and fungi in the rhizosphere soil of different disease-resistant pepper plants. 【Result】Through high-throughput sequencing, a total of 66 617 operational taxonomic units (OTUs) from soil bacterial samples were obtained, among which the dominant phyla were Proteobacteria and Bacteroidetes, with the relative abundances of approximately 40.1% and 15.3%, respectively. From soil fungal samples, 2 948 OTUs were obtained, among which the dominant phylum was Ascomycota, with an average relative abundance of approximately 47.8%. The rhizospheric microbial community structure and species composition of pepper varieties showed significant differences under different soil conditions. Under susceptible soil conditions, the diversity of bacterial communities in pepper rhizosphere decreased, while the diversity of fungal communities increased. The bacterial OTUs decreased by 6.5%-7.8%, and fungal OTUs increased by 8.8%-9.8%. The relative abundance of Fusarium fungi was significantly higher in the susceptible group (5.0%) compared with that in the resistant group (4.8%), while the relative abundance of beneficial fungi like Mortierella and Trichoderma and beneficial bacteria like Pseudomonas and Bacillus was significantly lower in the susceptible group than that in the resistant group. Overall, under the susceptible soil conditions, the abundance of beneficial rhizosphere fungi and bacteria in the resistant group was higher than that in the susceptible group, contributing to a better soil micro-ecological environment. Based on species abundance tables, the correlation relationships of fungi-fungi, fungi-bacteria and bacteria-bacteria species were calculated respectively at the genus level. The results indicated that the rhizosphere microorganisms of pepper formed a complex ecological network, with high co-occurrence between fungi-fungi and fungi-bacteria (with a positive correlation percentage higher than 50%), suggesting that cooperative relationships outweighed competitive ones. The bacteria-bacteria network structure was more complex, with a positive correlation percentage of about 49.9%.【Conclusion】The rhizospheric microbial community structures of different resistant varieties exhibit significant differences under different soil conditions. The interaction of rhizosphere microorganisms forms a complex microbial ecological network structure. The relative abundance of beneficial fungi and bacteria is higher in the resistant variety than that in the susceptible variety, which suppresses more pathogenic microbes, leading to a healthier soil micro-ecological environment. The key groups identified in this study, including Fusarium, Verticillium, Trichoderma, Bacillus and Pseudomonas, will provide important information for the targeted optimization of rhizospheric microbial community structures and offer crucial theoretical references for the biological control of soil-borne diseases. [ABSTRACT FROM AUTHOR]

Fusarium wilt, caused by Fusarium oxysporum f. sp. passiflorae (FOP), stands out as an obstacle to the production of Passiflora edulis Sims. Little is known about the interaction of FOP with substrates and pH ranges that can be used in the development of management strategies or selection for resistance in Passiflora spp. Thus, the effect of different soil: manure or soil: coconut fiber ratios with pH ranging from acidic to alkaline on the production of FOP propagules was evaluated. The experiment was carried out in a completely randomized design, using four soil: manure or soil: coconut fiber ratios (5:0, 5:2, 5:4, 5:6 (v:v)). Each mixture's pH was adjusted from 4.2 to 8.0 (soil: manure) or 4.2 to 9.7 (soil: coconut fiber). The production of microconidia, macroconidia, chlamydospores and colony forming units was evaluated at 3, 7, 14, 21 and 28 days after substrate infestation. The greatest number of propagules was registered in the groups treated with the highest proportions of manure or coconut fiber. The use of manure, regardless of the pH range, provided increases of 98%, 48%, and 13% in the number of colony forming units, microconidia and chlamydospores, respectively, in relation to the spores produced in substrates using coconut fiber. However, the production of macroconidia was 66% higher when fiber was used. Chlamydospore production was not affected by substrate pH, unlike other propagules with greater activity at slightly acidic, neutral or alkaline pH. The use of soil plus cattle manure in the ratios 5:4 or 5:6 with a pH between 5.1 and 8.0 was associated with the highest production of FOP propagules. [ABSTRACT FROM AUTHOR]

Fusarium wilt seriously endangers banana production, it causes yield loss and even no yield. It is spread by soil and transportation of seedlings, and chlamydospores of its pathogen survive in soil for 30 years. It is very difficult for the disease to be controlled, and it is always the focus of the government, academic field and banana industry. The experts, scholars, and related practitioners of domestic and abroad have done extensive and deep related research for solving this hard issue. This paper reviewed the previous research progress from the occurrence and harm of banana Fusarium wilt, the relationship between plant rhizosphere microecology and soil-borne diseases, banana rhizosphere microecology and their effects and contributions in Fusarium wilt control. The paper proposed the research trends of the interaction mechanism between Fusarium wilt and banana rhizosphere microecology, strain screening scope and isolating incubation methods, development and application of biocontrol agents with high efficiency and strong stability, aiming to provide references for subsequent in-depth study of banana rhizosphere microecology, the excavation and innovation utilization of excellent biological control resources and the efficient control of banana Fusarium wilt. [ABSTRACT FROM AUTHOR]

IntroductionFood security and waste management represent the main challenges that need to be addressed in the near future. The use of bioformulations and bioactive compounds obtained from agricultural wastes could represent some of the solutions for the management of soil-borne pathogens.MethodsIn the present study, Aureobasidium pullulans strain AP1, tested in oil dispersion (OD) formulation prototype and bio-extracts [hot water extract (HWE) and warm water extract (WWE)] derived from spent mushroom substrate (SMS) of Agaricus bisporus, was tested as sustainable strategies to manage Rhizoctonia solani of lettuce.ResultsBy in vitro assays, AP1OD at 600 mg L−1 displayed an inhibition by 57% of pathogen mycelial growth, and the SMS extract WWE (40°C) showed a growth stimulation of lettuce seedling by 27%. By In vivo assays, AP1OD formulation used against R. solani reduced by 66.6% the soil-borne pathogen incidence on lettuce plants, and both bio-extracts significantly stimulated lettuce leaves and roots growth (>200%). AP1OD formulation and HWE treatments increased the lettuce genes expression levels (ggps and hppd pdx1) mainly imputed to plant antioxidant potential, vitamin E, and vitamin B6 biosynthesis.DiscussionThe present study reported the potential of a new formulation and two bio-extracts, derived from an agricultural waste, to use against R. solani of lettuce, respectively, with antifungal and biostimulant properties.

The spread of antibiotic resistance genes (ARGs) and subsequent soil-borne disease outbreaks are major threats to soil health and sustainable crop production. However, the relationship between occurrences of soil-borne diseases and the transmission of soil ARGs remains unclear. Here, soil ARGs, mobile genetic elements and microbial communities from co-located disease suppressive and conducive banana orchards were deciphered using metagenomics and metatranscriptomics approaches. In total, 23 ARG types, with 399 subtypes, were detected using a metagenomics approach, whereas 23 ARG types, with 452 subtypes, were discovered using a metatranscriptomics method. Furthermore, the metagenomics analysis revealed that the ARG total abundance levels were greater in rhizospheres (0.45 ARGs/16S rRNA on average) compared with bulk (0.32 ARGs/16S rRNA on average) soils. Interestingly, metatranscriptomics revealed that the total ARG abundances were greater in disease-conducive (8.85 ARGs/16S rRNA on average) soils than disease suppressive (1.45 ARGs/16S rRNA on average) soils. Mobile genetic elements showed the same trends as ARGs. Network and binning analyses indicated that Mycobacterium, Streptomyces, and Blastomonas are the main potential hosts of ARGs. Furthermore, Bacillus was significantly and negatively correlated with Fusarium (P < 0.05, r = −0.84) and hosts of ARGs (i.e., Mycobacterium, Streptomyces, and Blastomonas). By comparing metagenomic and metatranscriptomic analyses，this study demonstrated that metatranscriptomics may be more sensitive in indicating ARGs activities in soil. Our findings enable the more accurate assessment of the transmission risk of ARGs. The data provide a new perspective for recognizing soil health, in which soil-borne disease outbreaks appear to be associated with ARG spread, whereas beneficial microbe enrichment may mitigate wilt disease and ARG transmission.

Mulberry bacterial wilt disease, caused by Ralstonia pseudosolanacearum, is a devastating soil-borne disease in the silk-mulberry-related industry. In this study, through high-throughput sequencing, we compared the rhizosphere bacterial composition of the mulberry-resistant cultivar (K10) and susceptible cultivar (G12), confirming Bacillus as a genus-level biomarker for K10. Next, twelve Bacillus spp. isolates, derived from the rhizosphere of K10, were screened for their antagonistic activity against R. pseudosolanacearum. The isolate showing strong antagonism was identified as B. velezensis K0T24 and selected for further analysis. The fermentation supernatant of B. velezensis K0T24 significantly inhibited the growth of R. pseudosolanacearum (82.47%) and the expression of its pathogenic genes. Using B. velezensis K0T24 in mulberry seedlings also increased defense enzyme activities and achieved a control efficacy of up to 55.17% against mulberry bacterial wilt disease. Collectively, our findings demonstrate the potential of B. velezensis K0T24 in suppressing mulberry bacterial wilt disease. [ABSTRACT FROM AUTHOR]

In a monocropping pattern for the crop domestication process, the interspecific and intraspecific interaction modes can be changed. In domesticated crops, the intraspecific interactions may have detrimental effects. Moreover, soil‐borne diseases in consecutive monocropped medicinal crops can be a critical challenge that has been difficult to solve. This study has been conducted to evaluate the effect of monoculture and intercropped cultivation on soil‐borne diseases caused by root secretions in American ginseng. The results of the correlation analysis showed that the polyethylenes in the roots had a more negative correlation with the occurrence of soil‐borne diseases than ginsenosides. Therefore, polyethylenes can be considered as an important factor in replanting failure of American ginseng. Furthermore, polyethylenes were able to remain in the soil and have a greater impact on the incidence of soil‐borne diseases than ginsenosides. [ABSTRACT FROM AUTHOR]

This article reports the first case of Meloidogyne enterolobii, a root-knot nematode, infecting white mulberry trees in Thailand. The infestation was discovered in an orchard in the Pak Chong district, Nakhon Ratchasima province, and was characterized by root gall symptoms without above-ground symptoms. The nematodes were identified through morphological examination and molecular identification techniques. Koch's postulates were also demonstrated to confirm the pathogenicity of M. enterolobii on mulberry trees. Further research is needed to understand the potential impacts of this nematode on mulberry cultivation in the region. [Extracted from the article]

A collection of Bacillus and Trichoderma isolates from Iran was investigated for the biological control of pear white root rot caused by Rosellinia necatrix. Among the isolates, B. amyloliquefaciens AP4, B. siamensis AP8 and T. harzianum T20a were selected based on their growth inhibition of R. necatrix in dual cultures, as well as by volatiles, diffusible extracts and culture filtrates. Four pear rootstocks (Pyrodwarf, OHF40, OHF60 and Williams) were assessed for white rot in the greenhouse following soil amendment with the three isolates. For OHF40 rootstock, none of the three isolates significantly reduced disease severity, whereas all three isolates significantly reduced disease severity for OHF69 rootstock. For Pyrodwarf rootstock, only T. harzianum T20a and B. amyloliquefaciens AP4 significantly reduced root rot, but all three isolates significantly reduced leaf fall. For Williams rootstock, all three isolates significantly reduced root rot, but only T. harzianum T20a significantly reduced leaf fall. Thus, the effectiveness of both the Bacillus and Trichoderma isolates was highly dependent upon the pear genotype. The lowest levels of white rot symptoms were observed in the Williams‐T. harzianum T20a interaction resulting in root rot severity of 46.6% and leaf fall of 4.7% at 70 dpi. While the effect of plant genotype on biocontrol activity has been reported frequently for Trichoderma, this is one of the first to report such an effect with a Bacillus biocontrol agent. Both Bacillus and Trichoderma can be effective biocontrol agents of pear white rot, but the plant genotype can have a major impact on their effectiveness. [ABSTRACT FROM AUTHOR]

Fusarium oxysporum f. sp. cubense tropical race 4 (FocTR4) is a devastating phytopathogen responsible for significant losses in banana production worldwide. Trichoderma and other biocontrol agents (BCAs) have been used as suitable disease control methods for banana Fusarium wilt. In this study, the endophytic T. koningiopsis Tk905 strain was isolated from the roots of dendrobe plants and identified utilizing morphological and molecular analyses. Antifungal activity tests revealed that Tk905 effectively inhibited mycelial growth with inhibition rates ranging from 26.52 to 75.34%. Additionally, Tk905 covered the pathogen mycelia, and spores were observed on or around the pathogen hyphae. The average root and shoot fresh weights and plant height, of Tk905-inoculated plants were significantly higher than those of the untreated plants. Furthermore, Tk905 treatment significantly increased the activity of antioxidant enzymes, such as catalase (CAT), phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO), and peroxidase (POD), suggesting that Tk905 may enhance plant defence systems by activating their antioxidant mechanisms. Most importantly, Tk905-treated plants inoculated by three methods exhibited significantly lower disease incidence and severity than untreated plants. The protective effects of Tk905 against FocTR4 infection were not only observed in the early stages of infection but persisted throughout the experiment, suggesting that T. koningiopsis Tk905 can provide long-lasting protection against Fusarium wilt. [ABSTRACT FROM AUTHOR]

The impact of plant health status change, specifically the effect of root rot infection, on rhizosphere microbial structure remains unclear. To address this knowledge gap, we investigated the dynamic variations in soil nutrient and rhizosphere microbial community during cowpea root rot infection. Samples of healthy and moderately to severely diseased cowpea rhizosphere soil were collected from a field in Xiangyang, Hubei, China, and high-throughput sequencing was used to detect changes in soil microbial communities. Our results showed that cowpea biomass decreased significantly with increased disease severity, and differences in soil pH and nutrients (NO3 --N, NH4 +-N, and available phosphorus) were observed between healthy and diseased rhizosphere, particularly under moderate diseased conditions. The process of root rot infection affected the bacterial and fungal community structure in the rhizosphere, but with inconsistent responses. Specifically, bacterial richness decreased with increased disease severity, while minor differences were observed in fungal alpha diversity. Principal coordinate analysis revealed significant disparities in rhizosphere bacteria and fungi under healthy and diseased conditions (moderate and severe). Moreover, while bacterial communities underwent notable alterations, fungal communities exhibited no significant changes between moderate and severe diseased conditions. In addition, Redundancy analysis showed that bacteria beta diversity was determined by available potassium and pH in the rhizosphere, whereas fungal beta diversity was determined by soil organic matter and pH. Overall, with root rot infection, both the soil nutrients and microbial community structure of cowpea significant changed. As a result, our study provides insights into the molecular mechanism underlying cowpea root rot and other plant rhizosphere microbial communities. [ABSTRACT FROM AUTHOR]

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BACKGROUND: As a registered non‐fumigant nematicide, abamectin has been widely used as a soil treatment against many cash crop nematode diseases. In a previous study, we found that soil adsorption hindered the stable performance of abamectin against root‐knot nematodes in the field. RESULTS: In this study, an efficient and labor‐saving application method of soil blending abamectin combined with rotary tillage, a common agronomic measure, was developed to improve the efficacy of abamectin against root‐knot nematode disease. We revealed the role of four parameters in this application method. At an abamectin dose of 750 g a.i. ha−1, spray water volume of 675 L ha−1 and rotation depth of 20 cm, abamectin was well distributed in the 0–20 cm soil layer at a concentration of 0.41–0.46 mg kg−1, the efficacy against root‐knot nematode disease was 72.12%, and the cucumber yield was 51.93 t ha−1. At the same dosage, root irrigation and flood irrigation measures resulted in only 29.28% and 33.43% control, with cucumber yields of 42.96 and 44.73 t ha−1, respectively. CONCLUSION: To control root‐knot nematode disease with abamectin, a soil blending application combined with rotary tilling is superior to leaching application combined with the agronomic measure of irrigation. The former application method can improve the dispersion of abamectin in the soil, enhance the efficacy of abamectin against root‐knot nematodes and maintain a stable cucumber yield. In addition, the increased labor required for application combined with agronomic measures is negligible and has excellent application prospects. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Although thaumatin-like proteins (TLPs) are involved in resistance to a variety of fungal diseases, whether the TLP5 and TLP6 genes in tomato plants (Solanum lycopersicum) confer resistance to the pathogenesis of soil-borne diseases has not been demonstrated. In this study, five soil-borne diseases (fungal pathogens: Fusarium solani, Fusarium oxysporum, and Verticillium dahliae; bacterial pathogens: Clavibacter michiganense subsp. michiganense and Ralstonia solanacearum) were used to infect susceptible "No. 5" and disease-resistant "S-55" tomato cultivars. We found that SlTLP5 and SlTLP6 transcript levels were higher in susceptible cultivars treated with the three fungal pathogens than in those treated with the two bacterial pathogens and that transcript levels varied depending on the pathogen. Moreover, the SlTLP5 and SlTLP6 transcript levels were much higher in disease-resistant cultivars than in disease-susceptible cultivars, and the SlTLP5 and SlTLP6 transcript levels were higher in cultivars treated with the same fungal pathogen than in those treated with bacterial pathogens. SlTLP6 transcript levels were higher than SlTLP5. SlTLP5 and SlTLP6 overexpression and gene-edited transgenic mutants were generated in both susceptible and resistant cultivars. Overexpression and knockout increased and decreased resistance to the five diseases, respectively. Transgenic plants overexpressing SlTLP5 and SlTLP6 inhibited the activities of peroxidase (POD), superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT) after inoculation with fungal pathogens, and the activities of POD, SOD, and APX were similar to those of fungi after infection with bacterial pathogens. The activities of CAT were increased, and the activity of β-1,3-glucanase was increased in both the fungal and bacterial treatments. Overexpressed plants were more resistant than the control plants. After SlTLP5 and SlTLP6 knockout plants were inoculated, POD, SOD, and APX had no significant changes, but CAT activity increased and decreased significantly after the fungal and bacterial treatments, contrary to overexpression. The activity of β-1,3-glucanase decreased in the treatment of the five pathogens, and the knocked-out plants were more susceptible to disease than the control. In summary, this study contributes to the further understanding of TLP disease resistance mechanisms in tomato plants. [ABSTRACT FROM AUTHOR]

Bacterial wilt is a soil-borne disease that causes severe damage in ginger-growing regions of Japan (eight prefectures in the Shikoku, Kyushu, and Honshu regions). Because the pathogen Ralstonia pseudosolanacearum usually lives in deeper soil and infects host plants via the roots, it is not easy to eliminate even with chemical pesticides (such as soil fumigants). In our previous study, we found that anaerobic soil disinfestation with diluted ethanol (Et-ASD) effectively eliminated this pathogen. We conducted field experiments to confirm the effectiveness of Et-ASD in a ginger monoculture system. Eight trials were conducted in seven different ginger fields from spring to autumn. Excluding one trial in early spring, seven trials in summer successfully eliminated the pathogen from the field soil (below the detection limit by the developed sensitive bio-PCR method), and no disease recurrence was observed after ASD treatment. In addition, other useful methods for controlling the disease were explored, including proper field management after the disease outbreak and the disinfection of seed rhizomes. Based on these results, a comprehensive control system for bacterial wilt disease in ginger was developed. [ABSTRACT FROM AUTHOR]

Verticillium wilt disease in cotton is a soil-borne disease that causes significant yield losses, and it is therefore important to identify disease-resistant genotypes. Current study was carried out in the experimental field of the Faculty of Agriculture, Dicle University (Diyarbakir) in the year 2020 to determine the tolerance levels of some cotton genotypes which contain different characteristics to wilt disease (Verticillium dahliae Kleb.). The experiment area has been naturally infected with Verticillium wilt pathogens. A total of 124 cotton genotypes, including four controls (DP-499, Edessa, ST-468, ES-1), were arranged in five blocks according to the Augmented Design. The indices of stem cross-section and the leaf-disease severity were found significant. The leaf-disease severity varied between 0.12-3.09 at 50-60 % at boll opening period, whilst stem cross-section values ranged between 0.36-2.30. Moreover, a positive correlation was found between the indices. In conclusion, G7, G12, G21, G22, G23, G41, G51, G55, and G101 were determined as tolerant genotypes to Verticillium wilt in terms of examining two parameters.

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]

Wheat crown rot, caused by Fusarium pseudograminearum, is an emerging soil-borne fungal disease and causes serious damage in areas where water is scarce. However, the interactions between plant, microbiome, and pathogen under different watering regimes are rarely known. In our study, we designed three watering patterns, including the early-drought (DR1), late-drought (DR2), and well-watered (WAT) patterns, and sampled at heading and grain filling, to investigate the effect of different watering regimes on the microbial community and disease severity. These findings showed that well-watered pattern at grain filling decreased the disease index compared to other patterns, and the bacterial community in the WAT and DR2 at grain filling showed higher alpha diversity (rhizosphere and root) and more stable structures (root). For the microbial network, irrespective of compartments, bacterial networks in the WAT and DR2 were more complex and connected with a higher average degree and clustering coefficient than DR1 at both periods. Furthermore, several potential beneficial microbes as biomarkers were enriched under good water conditions, specifically during the heading of DR2 and grain filling of WAT, including operational taxonomic units (OTUs) affiliated with the taxa of Arenimonas, Sphingomonas, Pseudoxanthomonas, Devosia, Lysobacter, Chitinophagaceae, and Gaiellales in the rhizosphere and root. Overall, the microbiome reshaped by good moisture or avoiding early drought should be emphasized and further used in controlling Fp-caused wheat crown rot. [ABSTRACT FROM AUTHOR]

Apple replant disease (ARD) is a worldwide economic risk in apple production. Although several studies have shown that the wild apple accession Malus × robusta 5 (Mr5) is ARD-tolerant, the genetics of this tolerance have not yet been elucidated. A genetic mapping approach with a biparental population derived from contrasting parents involving molecular markers provides a means for marker-assisted selection of genetically complex traits and for determining candidate genes. In this study, we crossed the ARD-tolerant wild apple accession Mr5 and the ARD-susceptible rootstock 'M9' and analyzed the resultant progeny for ARD tolerance. Hence, a high-density genetic map using a tunable genotyping-by-sequencing (tGBS) approach was established. A total of 4804 SNPs together with 77 SSR markers were included in the parental maps comprising 17 linkage groups. The phenotypic responses to ARD were evaluated for 106 offspring and classified by an ARD-susceptibility index (ASI). A Kruskal–Wallis test identified SNP markers and one SSR marker on linkage groups (LG) 6 and 2 that correlated with ARD tolerance. We found nine candidate genes linked with these markers, which may be associated with plant response to ARD. These candidate genes provide some insight into the defense mechanisms against ARD and should be studied in more detail. [ABSTRACT FROM AUTHOR]

Infection by the Japanese soil-borne wheat mosaic virus (JSBWMV) can lead to substantial losses in the grain yield of barley and wheat crops. While genetically based resistance to this virus has been documented, its mechanistic basis remains obscure. In this study, the deployment of a quantitative PCR assay showed that the resistance acts directly against the virus rather than by inhibiting the colonization of the roots by the virus' fungal vector Polymyxa graminis. In the susceptible barley cultivar (cv.) Tochinoibuki, the JSBWMV titre was maintained at a high level in the roots during the period December--April, and the virus was translocated from the root to the leaf from January onwards. In contrast, in the roots of both cv. Sukai Golden and cv. Haruna Nijo, the titre was retained at a low level, and translocation of the virus to the shoot was strongly suppressed throughout the host's entire life cycle. The roots of wild barley (Hordeum vulgare ssp. spontaneum) accession H602 responded in the early stages of infection similarly to those of the resistant cultivated forms, but the host was unable to suppress the translocation of the virus to the shoot from March onwards. The virus titre in the root was presumed to have been restricted by the action of the gene product of Jmv1 (on chromosome 2H), while the stochastic nature of the infection was suppressed by the action of that of Jmv2 (on chromosome 3H), a gene harbored by cv. Sukai Golden but not by either cv. Haruna Nijo or accession H602. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this study was to determine the effectiveness of cotton seed treatment with fungicides in the control of seedling damping-off caused by Rhizoctonia solani, under greenhouse conditions. Treated and untreated delinted seeds of the cultivar DeltaOpal were sowed in sand contained in plastic trays, placed in individual and equidistant wells, 3 cm deep. Into each plastic tray were put 3.0 g of the pathogen inoculum. The inoculation of R. solani AG-4 was done by the homogeneous distribution of the fungus inoculum onto the substrate. The fungus was grown for 35 days on autoclaved oat seeds and then ground to powder using a mill (1 mm). Fungicide seed treatments had a significant effect (P ≤ 0.05) on initial and final seedling emergence, pre and post-emergence damping-off, injured seedlings and disease index according to McKinney formula (lesion severity). The best results were obtained by fludioxonil + metalaxyl-M + azoxystrobin, fipronil + pyraclostrobin + methyl-thiophanate, carbendazim + thiram + pencycuron + baytan and carbendazim + thiram + pencycuron + baytan + procymidone. Pearson correlation analysis indicated that injured seedlings and disease index were positively correlated (R = 0.95). This means that the greater the number of injured seedlings, the greater the disease index and the less efficient the fungicide. The fungicides used in the present study did not have any phytotoxic effect on cotton seedlings.

Fluopimomide is a novel acid amide fungicide registered for the control of many plant pathogens. In the present study, the effects of soil-treated fluopimomide on soil micro biomass, disease incidence, plant growth, soil enzyme activity, and marketable yield of tomato (Solanum lycopersicum L.) were investigated via field trial. In addition, the application prospect in China was also evaluated. In the experiment, five treatments with three replications and a randomized complete block design were followed. The treatments were: furrow application of fluopimomide (25% suspension concentrate, SC) at the dosage of 375, 750, and 1,500 g ha−1, which was recommended, double recommended, and quadruple recommended dosages, respectively. Besides, common control fungicide fluopicolide (5% SC) furrow was applied at recommended application dosages of 750 mL ha−1, and a non-treated control was also undertaken. Results indicated that fluopimomide exhibited no effects on the amount of soil bacteria and actinomycetes, and its inhibition effect on fungi amount could be recovered at 60 days after treatment (DAT). With the recommended application dosage, fluopimomide could efficiently reduce the number of plant pathogens in soil by 79.56–85.80%, significantly reduce the disease incidences in tomato plants by 80.00–88.24%, and improve plant height by 13.25–24.05% and marketable yield by 16.88%. Furthermore, soil enzymes exhibited a complex response to fluopimomide, and AOB and nifH gene copy numbers were increased by the double and quadruple recommended dosage of fluopimomide. Based on the above results, fluopimomide could be recommended as an efficient fungicide for the tomato field.

Bacterial wilt, which is a major soil-borne disease with widespread occurrence, poses a severe danger in the field of tobacco production. However, there is very limited knowledge on bacterial wilt-induced microecological changes in the tobacco root system and on the interaction between Ralstonia solanacearum and fungal communities in the rhizosphere soil. Thus, in this study, changes in fungal communities in the rhizosphere soil of tobaccos with bacterial wilt were studied by 18S rRNA gene sequencing. The community composition of fungi in bacterial wilt-infected soil and healthy soil in two tobacco areas (Gengma and Boshang, Lincang City, Yunnan Province, China) was studied through the paired comparison method in July 2019. The results showed that there were significant differences in fungal community composition between the rhizosphere soil of diseased plants and healthy plants. The changes in the composition and diversity of fungal communities in the rhizosphere soil of tobaccos are vital characteristics of tobaccos with bacterial wilt, and the imbalance in the rhizosphere microecosystem of tobacco plants may further aggravate the disease.

In common root and crown rot (CRR), Bipolaris sorokiniana (Sace.) is one of the important in wheat, causing considerable yield losses globally. Sources of resistance can provide a feasible and effective method of control for plant disease management. However, knowledge on mechanisms of resistance is scarce.We screened 33 wheat genotypes against B. sorokiniana under greenhouse and field conditions. In addition, real‐time quantitative PCR (qPCR) analysis using ten novel candidate gene markers, Cre3, EDS1, LTP5, PGIP, PR‐1, PIEP1, TLP, UGT, Stb6 and PFT, was conducted on leaves and roots, along with changes in activity of antioxidant enzymes, peroxidase, catalase, β‐1,3‐glucanase, and phenolic content for their involvement in disease impact mechanisms.Lowest disease severity was in 'Alvand', followed by 'Baharan' and 'Bam' as resistant genotypes. Quantitative gene expression showed that, although the candidate defence genes were upregulated 1.24‐ to 3.5‐fold in wheat roots and leaves inoculated with B. sorokiniana, they were highly regulated in resistant varieties 'Alvand', 'Mehregan' and 'Bam'. Cre3, a resistance gene to cereal cyst nematode Heterodera filipjevi, was regulated in cultivars resistant to B. sorokiniana. Similar results were obtained for Stb6, a gene resistant to Septoria tritici blotch, EDS1 resistant to powdery mildew, Blumeria graminis, and the genes PR‐1 and UGT resistant to leaf rust, Puccinia triticina. Antioxidant enzyme activity also showed the highest increases in resistant genotypes.In conclusion, the T. aestivum–B. sorokiniana interaction in resistant wheat cultivars uses defence‐related genes and enzymes that protect wheat towards sustainable development. Further such studies will shed light on simultaneous resistance to other diseases in wheat cultivars. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the effectiveness of cotton seed treatment with fungicides in the control of seedling damping-off caused by Rhizoctonia solani, under greenhouse conditions. Treated and untreated delinted seeds of the cultivar DeltaOpal were sowed in sand contained in plastic trays, placed in individual and equidistant wells, 3 cm deep. Into each plastic tray were put 3.0 g of the pathogen inoculum. The inoculation of R. solani AG-4 was done by the homogeneous distribution of the fungus inoculum onto the substrate. The fungus was grown for 35 days on autoclaved oat seeds and then ground to powder using a mill (1 mm). Fungicide seed treatments had a significant effect (P = 0.05) on initial and final seedling emergence, pre and post-emergence damping-off, injured seedlings and disease index according to McKinney formula (lesion severity). The best results were obtained by fludioxonil + metalaxyl-M + azoxystrobin, fipronil + pyraclostrobin + methyl-thiophanate, carbendazim + thiram + pencycuron + baytan and carbendazim + thiram + pencycuron + baytan + procymidone. Pearson correlation analysis indicated that injured seedlings and disease index were positively correlated (R = 0.95). This means that the greater the number of injured seedlings, the greater the disease index and the less efficient the fungicide. The fungicides used in the present study did not have any phytotoxic effect on cotton seedlings. [ABSTRACT FROM AUTHOR]

The spread of antibiotic resistance genes (ARGs) and subsequent soil-borne disease outbreaks are major threats to soil health and sustainable crop production. However, the relationship between occurrences of soil-borne diseases and the transmission of soil ARGs remains unclear. Here, soil ARGs, mobile genetic elements and microbial communities from co-located disease suppressive and conducive banana orchards were deciphered using metagenomics and metatranscriptomics approaches. In total, 23 ARG types, with 399 subtypes, were detected using a metagenomics approach, whereas 23 ARG types, with 452 subtypes, were discovered using a metatranscriptomics method. Furthermore, the metagenomics analysis revealed that the ARG total abundance levels were greater in rhizospheres (0.45 ARGs/16S rRNA on average) compared with bulk (0.32 ARGs/16S rRNA on average) soils. Interestingly, metatranscriptomics revealed that the total ARG abundances were greater in disease-conducive (8.85 ARGs/16S rRNA on average) soils than disease suppressive (1.45 ARGs/16S rRNA on average) soils. Mobile genetic elements showed the same trends as ARGs. Network and binning analyses indicated that Mycobacterium , Streptomyces , and Blastomonas are the main potential hosts of ARGs. Furthermore, Bacillus was significantly and negatively correlated with Fusarium (P < 0.05, r = −0.84) and hosts of ARGs (i.e. , Mycobacterium , Streptomyces , and Blastomonas). By comparing metagenomic and metatranscriptomic analyses，this study demonstrated that metatranscriptomics may be more sensitive in indicating ARGs activities in soil. Our findings enable the more accurate assessment of the transmission risk of ARGs. The data provide a new perspective for recognizing soil health, in which soil-borne disease outbreaks appear to be associated with ARG spread, whereas beneficial microbe enrichment may mitigate wilt disease and ARG transmission. [Display omitted] • Soil-borne diseases and ARGs are strongly associated. • The total ARG abundances were greater in disease-conducive soils. • Mobile genetic elements showed the same trends as ARGs. • Mycobacterium, Streptomyces, and Blastomonas are the main potential hosts of ARGs. • Bacillus may contribute to reducing soil Fusarium and ARGs. [ABSTRACT FROM AUTHOR]

【Objective】Fusarium wilt and tobacco black shank, caused by Fusarium oxysporum and Phytophthora parasitica var. Nicotianae, are common soil-borne diseases in tobacco planting soil, leading to severe damages. Therefore, a rapid detection method for the two pathogens was established to provide technical support for disease epidemic and treatment in the process of tobacco planting and ensure the stable production of tobacco industry.【Method】Taking the soil with soil-borne disease and healthy soil in Baise area of Guangxi were used as test materials, and the standard curve was established with the standard pathogen as reference template. The primers were designed by the conservative regions of the two pathogens, and the specific primers were screened according to the target bands and the dissolution curve and Ct value of fluorescence quantitative PCR. At the same time, the extraction method of DNA kit of microbial in soil was improved, and the detection systems of PCR and qPCR were established.【Result】A pair of specific primers PN3 and JBR for F. oxysporum and P. parasitica var. nicotianae were screened respectively, and the template concentration ranged from 1×102 to 1×10-4 ng, with good linear relationship. The number of two pathogens in diseased soil was higher than that in healthy soil. The method of combination of soil drying, grinding and eluting for twice was helpful to extract the DNA of pathogens in the soil. A qPCR detection method with the products obtained by ordinary PCR pre-amplification reaction as a template was established.【Conclusion】The combination of PCR and qPCR can quickly distinguish and detect F. oxysporum and P. parasitica var. nicotianae, which plays an important role in real-time monitoring and early warning of fusarium wilt and tobacco black shank.

Sabina chinensis is a woody plant with important ecological functions in different regions of China, but its essential oils (EO) against plant pathogenic fungi remain largely undetermined. The purpose of our study was to assess the chemical composition and antifungal activity of S. chinensis EO based on optimization of the extraction process. In this study, an actionable and effective model with the experimental results and identified optimum conditions (crushing degree of 20 mesh, liquid-solid ratio of 10.1:1, immersion time of 9.1 h) was established successfully to achieve an extraction yield of 0.54%, which was basically consistent with the theoretical value. A total of 26 compounds were identified using headspace gas chromatography-mass spectrometry (GC-MS) and showed that the major constituent was bphellandrene (26.64-39.26%), followed by terpinen-4-ol (6.53-11.89%), bornyl acetate (6.13-10.53%), etc. For Petri plate assays, our experiments found for the first time that S. chinensis EO revealed high and long-term antifungal activity against the tested strains, including Fusarium oxysporum and Fusarium incarnatum, at EC50 values of 1.42 and 1.15 μL/mL, which especially reached approximately 76% and 90% growth inhibition at a dose of 0.2 μL/mL, respectively. Furthermore, the antifungal activity of EO from different harvest periods showed remarkable variation. The orthogonal partial least-squares discriminant analysis (OPLS-DA) method revealed 11 metabolites with chemical marker components, and 5 of its potential antifungal activities, terpinen-4-ol, a-terpineol, a-elemol, g-eudesmol, and bornyl acetate, were strongly correlated with the mycelial inhibition rate. In total, this study explored the antifungal activity of EO against root rot fungus as a potential fungicide and provided valuable information into developing potential products from natural agents. [ABSTRACT FROM AUTHOR]

Japanese soil-borne wheat mosaic virus (Furovirus) is a damaging pathogen of wheat and barley. This virus can survive in the soil for several decades, so the deployment of resistant cultivars represents the only practical control measure. Here, a genetic analysis has identified two regions of the barley genome--one on chromosome 2H and the other on chromosome 3H--as harboring gene(s) encoding resistance to this virus. The joint presence of both loci, termed Jmv1 and Jmv2, made the plants essentially immune, with resistance being dominant over susceptibility at each locus. Phylogenetic analysis showed that the virus is not closely related to the type Furovirus species Soil-borne wheat mosaic virus. There was a difference between the RNA1- and RNA2-based phylogenies of the virus species in Furovirus implying the independent segregation of the virus subgenomes. [ABSTRACT FROM AUTHOR]

Tuber rot is a major problem for the commercialization of the under-utilized Chinese yam (Dioscorea polystachya 'Nagaimo'), a tuber rich in nutrients and bioactive, health-promoting metabolites. Black to dark brown discoloration or indistinct lesions form on the surface of the tubers, and the discoloration spreads to internal tissues. Pseudomonas-like bacteria were isolated from lesions, caused the same symptoms in tubers after inoculation, and were identified as Pseudomonas allii based on phenotypic characteristics and phylogenetic features. This is the first report of bacterial rot caused by P. allii in Chinese yam. [ABSTRACT FROM AUTHOR]

Soil is the most biologically abundant ecosystem on the earth. Soil biodiversity has significant impact on maintaining soil ecological balance and agricultural production, especially on healthy growth and disease control of plants. Therefore, it is of great significance to study soil biodiversity. This paper reviewed the role of soil biodiversity in plant growth. First of all, the history of soil biodiversity was introduced. Secondly, the composition of soil biodiversity was introduced, and the role of soil biodiversity in regulating the quantity and species of soil organisms, maintaining the balance and stability of soil system, participating in nutrient circulation and energy flow, and promoting plant health were discussed based on the interactions among microbial diversity, fauna diversity and plant diversity. Finally, combined with the background of advocating the protection of soil biodiversity in the great time, the potential factors threatening soil biodiversity were analyzed. [ABSTRACT FROM AUTHOR]

Coating seeds with biocontrol agents represents an effective approach for managing soil-borne plant diseases. However, improving the viability of biocontrol microorganisms on the seed surface or in the rhizosphere remains a big challenge due to biotic and abiotic stresses. In this work, we developed a microbial seed coating strategy that uses sporopollenin exine capsules (SECs) as carriers for the encapsulation of the biofilm-like biocontrol bacteria. SECs was extracted from camellia bee pollen, and then characterized by Fourier Transform infrared spectroscopy (FTIR), elemental analysis and thermal gravity analysis (TG). The Paenibacillus polymyxa ZF129, a biocontrol bacterium, was introduced into SECs using the vacuum-incubation method and characterized by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). Notably, the ZF129 cell formed a biofilm-like structure inside the SECs, which enhanced their tolerance to acidic stress. As a proof of concept, we applied ZF129-loaded SECs to coat pak choi seeds using a straightforward plate-shaking technique. The coated seeds demonstrated a high control efficacy of up to 60.46 % against clubroot disease. Overall, this study sheds light on the application of SECs as promising carrier for the encapsulation of biofilm-like biocontrol bacteria, further augmenting the biocontrol functionality of microbial seed coating., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Soft rot (Pectobacterium aroidearum and Dickeya) is a devastating soil-borne bacterial disease that threatens konjac production. Intercropping with false acacia has been shown to significantly reduce soft rot incidence in konjac by shifting the microbial community. However, how intercropping shapes the root bacterial community and affects soft rot incidence remains unclear. To address this, we investigated three konjac intercropping systems (false acacia, paulownia, and maize) to explore the relationships among intercropping, soft rot incidence, root bacterial community, soil enzyme activity, and soil properties., Results: Konjac intercropped with false acacia exhibited the lowest soft rot incidence and the lowest abundance of pathogenic taxa. Soft rot incidence was negatively correlated with total soil nitrogen and potassium but positively correlated with total and available soil phosphorus. The bacterial community structure and function in konjac roots differed among intercropping types, mainly driven by available soil phosphorus. Beneficial microorganisms such as Bradyrhizobium and Variovorax were enriched under a false acacia intercropping system and were negatively correlated with soil-available phosphorus. Additionally, the stable bacterial community in healthy konjac roots under false acacia may make konjac less susceptible to pathogen invasion., Conclusion: The study showed that intercropping reduced the soft rot incidence by regulating the structure and stability of the konjac root bacterial community, and soil-available phosphorus was the main factor affecting the difference in the konjac root bacterial community, which provided a basis for the management of soil fertilization in konjac cultivation. © 2024 Society of Chemical Industry., (© 2024 Society of Chemical Industry.)

Bacterial wilt is a soil-borne disease that causes severe damage in ginger-growing regions of Japan (eight prefectures in the Shikoku, Kyushu, and Honshu regions). Because the pathogen Ralstonia pseudosolanacearum usually lives in deeper soil and infects host plants via the roots, it is not easy to eliminate even with chemical pesticides (such as soil fumigants). In our previous study, we found that anaerobic soil disinfestation with diluted ethanol (Et-ASD) effectively eliminated this pathogen. We conducted field experiments to confirm the effectiveness of Et-ASD in a ginger monoculture system. Eight trials were conducted in seven different ginger fields from spring to autumn. Excluding one trial in early spring, seven trials in summer successfully eliminated the pathogen from the field soil (below the detection limit by the developed sensitive bio-PCR method), and no disease recurrence was observed after ASD treatment. In addition, other useful methods for controlling the disease were explored, including proper field management after the disease outbreak and the disinfection of seed rhizomes. Based on these results, a comprehensive control system for bacterial wilt disease in ginger was developed.

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.

Wheat crown rot, caused by Fusarium pseudograminearum, is an emerging soil-borne fungal disease and causes serious damage in areas where water is scarce. However, the interactions between plant, microbiome, and pathogen under different watering regimes are rarely known. In our study, we designed three watering patterns, including the early-drought (DR1), late-drought (DR2), and well-watered (WAT) patterns, and sampled at heading and grain filling, to investigate the effect of different watering regimes on the microbial community and disease severity. These findings showed that well-watered pattern at grain filling decreased the disease index compared to other patterns, and the bacterial community in the WAT and DR2 at grain filling showed higher alpha diversity (rhizosphere and root) and more stable structures (root). For the microbial network, irrespective of compartments, bacterial networks in the WAT and DR2 were more complex and connected with a higher average degree and clustering coefficient than DR1 at both periods. Furthermore, several potential beneficial microbes as biomarkers were enriched under good water conditions, specifically during the heading of DR2 and grain filling of WAT, including operational taxonomic units (OTUs) affiliated with the taxa of Arenimonas, Sphingomonas, Pseudoxanthomonas, Devosia, Lysobacter, Chitinophagaceae, and Gaiellales in the rhizosphere and root. Overall, the microbiome reshaped by good moisture or avoiding early drought should be emphasized and further used in controlling Fp-caused wheat crown rot.

Exploring the potential of organic fertilizers as a mitigating strategy against the negative consequences induced by prolonged use of inorganic fertilizers in high-intensity banana cultivation is critically essential. Ammonia-oxidizer are closely linked to soil acidification, and how they respond to the long term fertilized banana field soil still poorly understood. In this study, soil samples from long-term inorganic (CF), and inorganically plus organically fertilized banana fields (OF) (from 2010 to 2019) were used to investigate the soil acid buffer capacity (pHBC), the potential nitrification rate (PNR), and the community structure of bacteria, fungi, ammonia-oxidizing archaea (AOA), and bacteria (AOB). Compared to the natural soil (CK, unplanted, and unfertilized), the pH and pHBC in the long-term fertilized banana field (both CF and OF) were significantly reduced. However, the pHBC was 1.3 times higher in soil receiving OF treatment than that in CF treatment. Organic matter (OM) and total nitrogen (TN) were significantly increased in the OF treated soil, which were 1.88 and 1.6 times higher compared to the CF-treated ones. The PNR in banana soil was 3.71–4.85 times higher than in the natural soil. High-throughput sequencing results showed that Candidatus Nitrosospharea SCA1170 -like AOA and Nitrosospira spp-like AOB were adapted to long-term fertilization in banana field soil. Potentially pathogenic bacteria, Xanthomonadaceae , were enriched in CF-treated soil compared to CK and OF soils. Opposingly, potentially beneficial Streptomyces and Arthrobacter were enriched in natural soil. Meanwhile, the OF-treated soil demonstrated a greater abundance of beneficial Bacillus and Alicyclobacillus. The study reveals that organic fertilizers ameliorate soil acidification, low organic matter content and microbial diversity compared to inorganic fertilizers for banana cultivation. [Display omitted] • Nitrosospira spp-like AOB promotes soil acidification in long-term fertilized banana fields. • The use of organic fertilization increase soil acid-buffering capacity. • The use of organic fertilization recruit beneficial Bacillus and Alicyclobacillus in the banana soil. [ABSTRACT FROM AUTHOR]

Apple replant disease (ARD) is a worldwide economic risk in apple production. Although several studies have shown that the wild apple accession Malus × robusta 5 (Mr5) is ARD-tolerant, the genetics of this tolerance have not yet been elucidated. A genetic mapping approach with a biparental population derived from contrasting parents involving molecular markers provides a means for marker-assisted selection of genetically complex traits and for determining candidate genes. In this study, we crossed the ARD-tolerant wild apple accession Mr5 and the ARD-susceptible rootstock ‘M9’ and analyzed the resultant progeny for ARD tolerance. Hence, a high-density genetic map using a tunable genotyping-by-sequencing (tGBS) approach was established. A total of 4804 SNPs together with 77 SSR markers were included in the parental maps comprising 17 linkage groups. The phenotypic responses to ARD were evaluated for 106 offspring and classified by an ARD-susceptibility index (ASI). A Kruskal–Wallis test identified SNP markers and one SSR marker on linkage groups (LG) 6 and 2 that correlated with ARD tolerance. We found nine candidate genes linked with these markers, which may be associated with plant response to ARD. These candidate genes provide some insight into the defense mechanisms against ARD and should be studied in more detail.

Arbuscular mycorrhizal (AM) fungi play a vital role in plant's resistance against soil‐borne pathogens including Phytophthora capsici, which causes the devastating Phytophthora blight and threatens pepper (Capsicum annuum L.) cultivation worldwide. In order to understand the interaction of indigenous AM fungal community and P. capsici during the aggravation of Phytophthora blight, a survey was performed in a facility shed in Southwest China. The blight severity of pepper plants was evaluated based on a 0–5 scale (L0–L5), and the corresponding root AM fungal colonization, and the abundance and community composition of AM fungi as well as the population of P. capsici in root‐adjacent soil, were all investigated. Along with the rise of disease severity, increased soil P. capsici population was shown. In contrast, there were significant decreases in root colonization rate and the diversity indices rather than the abundance of soil AM fungi. The root colonization rate and the diversity indices of AM fungi all showed significant negative correlations with soil P. capsici population. Compared to plants with lower disease severities (L0–L2), higher severities (L3–L5) significantly modified soil AM fungal community composition, mainly through replacing the beneficial Glomus phylotypes by Paraglomus ones. Overall, the results disclosed the dynamic competition between indigenous AM fungi and P. capsici behind the onset of pepper Phytophthora blight, which highlights the importance of establishing soil suppressiveness on the control of soil‐borne diseases. [ABSTRACT FROM AUTHOR]

Apple replant disease (ARD) is a worldwide economic risk in apple cultivation for fruit tree nurseries and fruit growers. Several studies on the reaction of apple plants to ARD are documented but less is known about the genetic mechanisms behind this symptomatology. RNA-seq analysis is a powerful tool for revealing candidate genes that are involved in the molecular responses to biotic stresses in plants. The aim of our work was to find differentially expressed genes in response to ARD in Malus. For this, we compared transcriptome data of the rootstock 'M9' (susceptible) and the wild apple genotype M. × robusta 5 (Mr5, tolerant) after cultivation in ARD soil and disinfected ARD soil, respectively. When comparing apple plantlets grown in ARD soil to those grown in disinfected ARD soil, 1,206 differentially expressed genes (DEGs) were identified based on a log2 fold change, (LFC) ≥ 1 for up– and ≤ −1 for downregulation (p < 0.05). Subsequent validation revealed a highly significant positive correlation (r = 0.91; p < 0.0001) between RNA-seq and RT-qPCR results indicating a high reliability of the RNA-seq data. PageMan analysis showed that transcripts of genes involved in gibberellic acid (GA) biosynthesis were significantly enriched in the DEG dataset. Most of these GA biosynthesis genes were associated with functions in cell wall stabilization. Further genes were related to detoxification processes. Genes of both groups were expressed significantly higher in Mr5, suggesting that the lower susceptibility to ARD in Mr5 is not due to a single mechanism. These findings contribute to a better insight into ARD response in susceptible and tolerant apple genotypes. However, future research is needed to identify the defense mechanisms, which are most effective for the plant to overcome ARD. [ABSTRACT FROM AUTHOR]

Fusarium root rot caused by Fusarium solani severely damages the roots of Panax notoginseng (ginseng) seedlings eventually leading in most cases to the total loss of this valuable crop. Soil fumigants are generally better at controlling soil-borne diseases such as F. solani than fungicides which provide unacceptable control. We tested the efficacy of two fumigants allyl isothiocyanate (AITC) and dimethyl disulfide (DMDS) against F. solani in the laboratory. AITC inhibited F. solani mycelial growth completely at a concentration of 1.2 μg/L and significantly reduced CO2 emissions of F. solani. Ultrastructural studies showed that AITC disrupted the cell membrane of F. solani by causing plasmolysis and plasma leakage. AITC had multiple modes of action affecting F. solani cell respiration, plasmolysis and cell membrane function. However, the inhibitory effect of DMDS was slightly less than AITC which was mostly ineffective against F. solani. In all, AITC but not DMDS effectively controlled F. solani in ginseng production and could therefore be recommended as controls for this disease as a component of an integrated pest management program. [ABSTRACT FROM AUTHOR]

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Apple replant disease (ARD) is a worldwide economic risk in apple cultivation for fruit tree nurseries and fruit growers. Several studies on the reaction of apple plants to ARD are documented but less is known about the genetic mechanisms behind this symptomatology. RNA-seq analysis is a powerful tool for revealing candidate genes that are involved in the molecular responses to biotic stresses in plants. The aim of our work was to find differentially expressed genes in response to ARD in Malus. For this, we compared transcriptome data of the rootstock ‘M9’ (susceptible) and the wild apple genotype M. ×robusta 5 (Mr5, tolerant) after cultivation in ARD soil and disinfected ARD soil, respectively. When comparing apple plantlets grown in ARD soil to those grown in disinfected ARD soil, 1,206 differentially expressed genes (DEGs) were identified based on a log2 fold change, (LFC) ≥ 1 for up– and ≤ −1 for downregulation (p

ABSTRACT The often widespread and serious Root-Knot Nematode (RKN) disease is an important soil-borne disease affecting tobacco production. This study aimed to understand micro-ecological changes caused by RKN disease and interactions between disease and rhizosphere soil fungal communities. The 18S rRNA gene sequencing was used to study changes in rhizosphere fungal community of tobacco plants having RKN disease. In June 2018, a paired comparison was performed between rhizosphere fungal community structures of healthy tobacco plants and those with RKN disease in Yuxi and Jiuxiang, Yunnan Province, China. Compared with uninfested soil, the OTU abundance, Shannon, ACE and Chao1 indexes of infested soil in the two tobacco areas showed a decreasing trend. Principal Coordinate Analysis showed fungal communities of infested soil and uninfested soil in the two tobacco areas were clustered in different areas, and the community composition was significantly different. Moreover, the dominant fungi community and relative abundance are significantly different at phylum, genus and species levels. More beneficial fungi, such as Penicillium and Aspergillus, were found in soil samples of healthy plants, whereas more pathogenic fungi, such as Phoma and Alternaria, were found in soil samples of diseased plants. In conclusion, changes in fungal community structure and decreases in species diversity and richness were important characteristics of rhizosphere soils from diseased tobacco plants. Disequilibrium in the tobacco rhizosphere micro-ecosystem may allow the development of RKN disease and other more complex diseases.