Root-knot nematodes (RKN; Meloidogyne spp.) are widely distributed endoparasites that severely damage myriad crops and vegetables. This study aimed to evaluate the nematicidal effect of secondary metabolites (SMs) from the co-culture of Burkholderia vietnamiensis B418 and Trichoderma harzianum T11-W (B + T co-culture) against RKN. The in vitro inhibition efficiency of fermentation filtrate of B + T co-culture achieved 93.79% on nematode eggs and caused eggshell rupture within 24 h. The fermentation broth of B + T co-culture exhibited a considerable control effect of 73.45% against RKN infestation on tomato in pot experiment, outperforming B418 (51.31%) and T11-W (42.89%) mono-cultures. Additionally, B + T co-culture treatment significantly reduced root gall incidence, promoted root development, elevated antioxidative enzyme activities in leaves and roots, and increased leaves chlorophyll content. Ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis identified 795 and 478 metabolites in positive and negative ion modes, respectively. Metabolomic profiles revealed nematicidal and growth-promoting SMs in B + T co-culture, including 3-[(4-hydroxyphenyl)methyl]-octahydropyrrolo[1,2-a]pyrazine-1,4-dione (cyclo(L-Pro-L-Tyr)), 3-(propan-2-yl)-octa-hydropyrrolo[1,2-a]pyrazine-1,4-dione (cyclo(L-Pro-L-Val)), 3-(2-methylpropyl)-octahydropyrrolo[1,2-a]pyr-azine-1,4-dione (cyclo(D-Leu-L-Pro)), indole-3-acrylic acid (IAA), indole-2-carboxylic acid (ICA), bafilomycin B1, norfloxacin, p-hydroxybenzaldehyde (PHBA), styrene, 4-methylphenol, and organic acids. The up-regulated accumulation of these metabolites provides a molecular basis for the enhanced RKN inhibitory efficacy, confirming that the co-culture of B. vietnamiensis and T. harzianum facilitates the biosynthesis of nematicidal SMs, which holds substantial potential for RKN management.

Salt stress severely impacts a plant's root development. This study explores the role of volatile organic compounds (VOCs) from Trichoderma harzianum ST02 in enhancing adventitious root development of peppermint (Mentha × piperita), an important salt-tolerant medicinal plant, under salt stress. Peppermint seedlings were subjected to NaCl concentrations (0, 50, 100, and 150 mM) with or without exposure to T. harzianum ST02 VOCs. Morphological analyses revealed that VOCs significantly increased adventitious root numbers and total root length under salt stress, alleviating NaCl-induced damage. Gas chromatography-mass spectrometry (GC-MS) analysis found 3(2H)-furanone, dihydro-2-methyl, as a predominant component in T. harzianum ST02 VOCs. Transcriptomic analysis via RNA sequencing (RNA-seq) for four groups under different treatments identified 5589 differentially expressed genes (DEGs), with 298 DEGs specifically linked to VOCs exposure under 100 mM NaCl stress. Functional annotation indicated enrichment in pathways related to secondary metabolism and plant hormone signal transduction. VOCs modulated key genes, including those encoding ion transporters (e.g., SLAH2 and ABCG14), reactive oxygen species (ROS) scavenging (e.g., peroxidases), and cell wall-modifying enzymes (e.g., XTH). Notably, VOCs downregulated genes involved in abscisic acid (ABA) and ethylene biosynthesis (NCED3, ACS, and ACO), reducing stress signaling, while upregulating auxin (GH3.1) and gibberellin (GA2ox) metabolism genes, promoting root development. These findings suggest that T. harzianum ST02 VOCs enhance peppermint's salt tolerance by coordinately regulating hormone signaling, ion transport, and cell wall remodeling, thereby facilitating adventitious root development. Our work provides a molecular framework for utilizing beneficial microbes to improve plant resilience in saline environments.

The interaction of plant and soil microbiome is a source of ecosystem complexity with implications for plant adaptation to environmental stress. However, the three-fold interaction between plant genotype, soil microbiome, and environment remains largely unexplored. In legumes the interactions involve rhizobia in soil and plant nodules. This study used a plasticity perspective to investigate the rhizosphere soil and legume nodule microbiome in a factorial combining four contrasting chickpea (Cicer arientinium L.) genotypes and five rainfed field environments spanning a 10-fold range of plant productivity primarily associated with drought stress. We quantified the rhizosphere effect (RE) as the normalised difference in diversity of microbial communities between bulk soil and rhizosphere, and its plasticity in response to environment. Rhizosphere effect was genotypedependent and varied with bacterial and fungal communities. Two genotypes maintained a stable RE regardless of conditions, and two genotypes enhanced recruitment of bacterial communities under increasing stress. Genotypic ability to modulate the rhizosphere bacteriome was negatively correlated with their N fixation under harsh conditions (r = -0.7). Fungal RE showed a non-linear relationship with environmental stress, peaking at moderate stress in all chickpea genotypes. In the nodules, symbiotic rhizobia consistently dominated (similar to 95% abundance) across all environments and genotypes, resulting in a low plasticity of nodulation effect on microbial recruitment. We identified and isolated four non-rhizobial bacterial strains (Burkholderia spp. and Pseudomonas spp.) that stably colonised nodules. Three of these strains promoted nodulation and N fixation through production of indole-3-acetic acid. In an agronomically relevant, large-scale field setting, we provide novel insights into the role of plant microbiome plasticity with implications for legume productivity in drylands.

Root-knot nematodes (RKNs; Meloidogyne incognita) pose a significant threat to tomato crops, necessitating sustainable control methods. This study investigated the inoculation efficacy of co-cultured Burkholderia vietnamiensis B418 and Trichoderma harzianum T11W compared with single-strain treatments for RKNs suppression and their influence on the structure and function of the rhizosphere microbiome. Co-inoculation with B418 + T11W achieved a 71.42% reduction in the disease index, significantly outperforming single inoculations of B418 (54.46%) and T11W (58.93%). Co-inoculation also increased plant height by 38.51% and fresh weight by 76.02% compared to the RKNs infested plants control, promoting robust tomato growth. Metagenomic analysis reveals that co-inoculation enhanced bacterial diversity, with 378 unique bacterial species and a high Shannon index, while fungal diversity decreased with Trichoderma dominance (83.31% abundance). Actinomycetota (46.42%) and Ascomycota (97.92%) were enriched in the co-inoculated rhizosphere, showing negative correlations with RKNs severity. Functional analysis indicates enriched metabolic pathways, including streptomycin and unsaturated fatty acid biosynthesis, enhancing microbial antagonism. Single inoculations altered pathways like steroid degradation (B418) and terpenoid biosynthesis (T11W), but co-inoculation uniquely optimized the rhizosphere microenvironment. These findings highlight co-inoculation with B418 + T11W effectively suppressing RKNs and fostering plant health by reshaping microbial communities and functions, offering a promising approach for sustainable agriculture.

Biocontrol by inoculation with beneficial microbes is a proven strategy for reducing the negative effect of soil-borne pathogens. The effects of Trichoderma harzianum LTR-2 and Arthrobacter ureafaciens DnL1-1 on reducing Fusarium crown rot (FCR) disease and influencing microbial community structure in wheat root-zone were evaluated by a plot experiment. The experimental design consisted of four treatments: (1) control, (2) Fusarium pseudograminearum Fp (FP), (3) F. pseudograminearum + LTR-2 (LFP), and (4) F. pseudograminearum + LTR-2 + DnL1-1 (HFP). The results showed that wheat seeds coated with LTR-2 spore suspension and combination of LTR-2 and DnL1-1 had relative control efficacies of 50.77% and 67.73% on FCR disease, and increased wheat yield by 58.32% and 64.19%, respectively. Illumina MiSeq sequencing revealed that bacterial and fungal abundance and diversity were significantly higher ( P < 0.05) in both treatment groups (HFP and LFP) than in FP and control groups. Principal coordinates analyses revealed that fungal and bacterial communities were distinctly separated among the treatment and control groups. Fungal community composition analysis demonstrated that the relative abundance of phytopathogenic fungi Alternaria , Fusarium , and Cladosporium decreased and that of beneficial fungi Mortierella and Gamsia was more enriched in HFP and LFP than in FP group. Bacterial community composition analysis revealed that the beneficial microbes, such as Bacillus and Streptomyces were more abundant in HFP and LFP than in FP group. LEfSe analysis indicated that the key different genera, e.g. Tetracladium (fungus), Sphingomonas and Ramlibacter (bacteria), which were significantly negatively correlated with TP in HFP treatment. It was concluded that application of LTR-2 and DnL1-1 may recruit a variety of phosphate-solubilizing microbes to promote wheat growth. Overall, these results confirm that the relative abundance of phytopathogenic fungi decreased significantly following application of LTR-2 alone and combined with DnL1-1 and beneficial microbes accumulated more easily in the wheat root-zone compared with that in FP and control groups.

Salt stress poses a major threat to plant growth, and breeding for salt-tolerant varieties is not always successful to ameliorate this threat. In the present experiment, the effect of T. asperellum 22043 inoculation on the growth of salt-stressed tomatoes and the mechanisms by which it improves salt tolerance were investigated. It was observed that tomato plants treated with T. asperellum 22043 spore suspension under salt tress (50 and 100 mM NaCl) consistently exhibited higher seeds germination, seedling survival rate, plant height, and chlorophyll content, but lower malondialdehyde and proline contents than the plants treated without the Trichoderma. T. asperellum 22043 effectively improved the stress resistance of tomato through regulating the transcriptional levels of reactive oxygen species (ROS) scavenging enzyme gene expression to modulate the activity of ROS scavenging enzymes and the expression of the genes related to transporter and aquaporin to maintain the balance of cell Na+. In conclusion, T. asperellum 22043 can enhance tomato seedlings’ salt tolerance by activating the antioxidant system and regulating the expression of stress-resistant genes.

Background/Objectives: This study investigated the effects of chestnut tannic acid (TA) on the growth performance, the expression of tight junction proteins and the composition of the gut microbiota of weaned piglets, which could provide novel insights into the application of TA in swine production. Methods: In a 42-day trial, 180 healthy, 21-day-old Duroc × Landrace × Yorkshire piglets were randomly assigned to a Control group and four treatment groups (TA1–4), fed commercial diets supplemented with 0, 0.06%, 0.12%, 0.18% or 0.24% TA. Each group had six replicates of six pigs each. Results: The average daily gain in all TA groups, the jejunal and ileal villus height and the villus height-to-crypt depth ratio in the TA3 and TA4 groups were markedly increased (p < 0.05). The mRNA levels of MUC2 and ZO-1 were upregulated in the TA3 group, as were those of MUC4 in the jejunum and ileum and claudin in the duodenum and ileum; glutathione peroxidase and total antioxidant capacity were upregulated in the duodenum and jejunum in the TA3 group, and total superoxide dismutase was increased in all the TA2 groups (p < 0.05). Conversely, the malondialdehyde significantly decreased in all the TA groups (p < 0.05). TA supplementation improved the alpha diversity of the intestinal microflora and augmented probiotic abundance while reducing that of pathogenic bacteria. The contents of acetic, isobutyric, valeric, isovaleric, hexanoic and propionic acids, as well as total short-chain fatty acids (SCFA), were higher in the TA2 and TA3 groups (p < 0.05). Conclusions: TA inclusion in piglet diets improved the intestinal environment by upregulating the antioxidant enzymes, improving intestinal morphology and promoting probiotic growth and SCFA production while reducing pathogenic bacterial abundance, consequently enhancing the gut barrier and the growth of weaned piglets.

Strawberry anthracnose caused by Colletotrichum spp. has resulted in significant losses in strawberry production worldwide. Strawberry anthracnose occurs mainly at the seedling and early planting stages, and Colletotrichum siamense is the main pathogen in North China, where mycelia, anamorphic nuclei, and conidia produced in the soil are the main sources of infection. The detection of pathogens in soil is crucial for predicting the prevalence of anthracnose. In this study, a visualized loop-mediated isothermal amplification (LAMP) assay and a loop-mediated isothermal amplification method combined with a TaqMan probe (LAMP-TaqMan) assay were developed for the β-tubulin sequence of C. siamense. Both methods can detect Colletotrichum siamense genomic DNA at very low concentrations (104 copies/g) in soil, while both the visualized LAMP and LAMP-TaqMan assays exhibited a detection limit of 50 copies/μL, surpassing the sensitivity of conventional PCR and qPCR techniques, and both methods showed high specificity for C. siamense. The two methods were compared: LAMP-TaqMan exhibited enhanced specificity due to the incorporation of fluorescent molecular beacons, while visualized LAMP solely necessitated uncomplicated incubation at a constant temperature, with the results determined by the color change; therefore, the requirements for the instrument are relatively straightforward and user-friendly. In conclusion, both assays will help monitor populations of C. siamense in China and control strawberry anthracnose in the field.

Recently, there has been a growing interest in the biocontrol activity of volatile organic compounds (VOCs) produced by microorganisms. This study specifically focuses on the effects of VOCs produced by the co-culture of Burkholderia vietnamiensis B418 and Trichoderma harzianum T11-W for the control of two phytopathogenic fungi, Botrytis cinerea and Fusarium oxysporum f. sp. cucumerium Owen. The antagonistic activity of VOCs released in mono- and co-culture modes was evaluated by inhibition assays on a Petri dish and in detached fruit experiments, with the co-culture demonstrating significantly higher inhibitory effects on the phytopathogens on both the plates and fruits compared with the mono-cultures. Metabolomic profiles of VOCs were conducted using the solid-liquid microextraction technique, revealing 341 compounds with significant changes in their production during the co-culture. Among these compounds, linalool, dimethyl trisulfide, dimethyl disulfide, geranylacetone, 2-phenylethanol, and acetophenone were identified as having strong antagonistic activity through a standard inhibition assay. These key compounds were found to be related to the improved inhibitory effect of the B418 and T11-W co-culture. Overall, the results suggest that VOCs produced by the co-culture of B. vietnamiensis B418 and T. harzianum T11-W possess great potential in biological control.

Trichoderma spp. is known for its ability to enhance plant growth and suppress disease, but the mechanisms for its interaction with host plants and pathogens remain unclear. This study investigated the transcriptomics and metabolomics of peanut plants (Arachis hypogaea L.) inoculated with Trichoderma harzianum QT20045, in the absence and presence of the stem rot pathogen Sclerotium rolfsii JN3011. Under the condition without pathogen stress, the peanut seedlings inoculated with QT20045 showed improved root length and plant weight, increased indole acetic acid (IAA) production, and reduced ethylene level, with more active 1-aminocyclopropane-1-carboxylate acid (ACC) synthase (ACS) and ACC oxidase (ACO), compared with the non-inoculated control. Under the pathogen stress, the biocontrol efficacy of QT20045 against S. rolfsii was 78.51%, with a similar effect on plant growth, and IAA and ethylene metabolisms to the condition with no biotic stress. Transcriptomic analysis of peanut root revealed that Trichoderma inoculation upregulated the expression of certain genes in the IAA family but downregulated the genes in the ACO family (AhACO1 and AhACO) and ACS family (AhACS3 and AhACS1) consistently in the absence and presence of pathogens. During pathogen stress, QT20045 inoculation leads to the downregulation of the genes in the pectinesterase family to keep the host plant’s cell wall stable, along with upregulation of the AhSUMM2 gene to activate plant defense responses. In vitro antagonistic test confirmed that QT20045 suppressed S. rolfsii growth through mechanisms of mycelial entanglement, papillary protrusions, and decomposition. Our findings highlight that Trichoderma inoculation is a promising tool for sustainable agriculture, offering multiple benefits from pathogen control to enhanced plant growth and soil health.

Fusarium crown rot (FCR) caused by Fusarium pseudograminearum is a serious threat to wheat production worldwide. This study aimed to assess the effects of Talaromyces muroii strain TM28 isolated from root of Panax quinquefolius against F. pseudograminearum. The strain of TM28 inhibited mycelial growth of F. pseudograminearum by 87.8% at 72 h, its cell free fermentation filtrate had a strong antagonistic effect on mycelial growth and conidial germination of F. pseudograminearum by destroying the integrity of the cell membrane. In the greenhouse, TM28 significantly increased wheat fresh weight and height in the presence of pathogen Fp, it enhanced the antioxidant defense activity and ameliorated the negative effects of F. pseudograminearum, including disease severity and pathogen abundance in the rhizosphere soil, root and stem base of wheat. RNA-seq of F. pseudograminearum under TM28 antagonistic revealed 2,823 differentially expressed genes (DEGs). Most DEGs related to cell wall and cell membrane synthesis were significantly downregulated, the culture filtrate of TM28 affected the pathways of fatty acid synthesis, steroid synthesis, glycolysis, and the citrate acid cycle. T. muroii TM28 appears to have significant potential in controlling wheat Fusarium crown rot caused by F. pseudograminearum.

This study aimed to investigate the efficiency of the secondary metabolites (SMs) produced by a co-culture of Trichoderma harzianum TW21990 and Burkholderia vietnamiensis B418 in the control of Colletotrichum siamense CM9. A fermentation filtrate of B418 + TW21990 co-culture (BT21) produced a notable increase in the inhibition rate of CM9 compared to those of TW21990 and B418 monocultures, which reached 91.40% and 80.46% on PDA plates and strawberry leaves, respectively. The BT21 fermentation broth exhibited high control efficiency on strawberry root rot of 68.95% in a pot experiment, which was higher than that in the monocultures and fluazinam treatment. In addition, BT21 treatment promoted strawberry root development, improved antioxidative enzyme activities in the leaves and roots, and enhanced the total chlorophyll content of the strawberry leaves. UHPLC-MS/MS analysis of fermentation filtrates was performed to elucidate SM variations, revealing 478 and 795 metabolites in BT21 co-culture in positive and negative ion modes, respectively. The metabolomic profiles suggested abundant SMs with antagonistic capabilities and growth-promoting effects: 3-(propan-2-yl)-octahydropyrrolo [1,2-a]pyrazine-1,4-dione (cyclo(L-Pro-L-Val)), 3-[(4-hydroxyphenyl)methyl]-octahydropyrrolo[1,2-a]pyrazine-1,4-dione (cyclo(L-Pro-L-Tyr)), 3-indoleacetic acid (IAA), 2-hydroxycinnamic acid, 4-aminobutyric acid (GABA), bafilomycin B1, and DL-indole-3-lactic acid (ILA) were significantly enhanced in the co-culture. Overall, this study demonstrates that a co-culture strategy is efficient for inducing bioactive SMs in T. harzianum and B. vietnamiensis, which could be exploited as a novel approach for developing biocontrol consortia.

Terpenoids are structurally diverse natural products that have been widely used in the pharmaceutical, food, and cosmetic industries. Research has shown that fungi produce a variety of terpenoids, yet fungal terpene synthases remain not thoroughly explored. In this study, the tps1 gene, a crucial component of the terpene synthetic pathway, was isolated from Trichoderma atroviride HB20111 through genome mining. The function of this gene in the terpene synthetic pathway was investigated by constructing tps1-gene-deletion- and overexpression-engineered strains and evaluating the expression differences in the tps1 gene at the transcript level. HS-SPME-GC-MS analysis revealed significant variations in terpene metabolites among wild-type, tps1-deleted (Δtps1), and tps1-overexpressed (Otps1) strains; for instance, most sesquiterpene volatile organic compounds (VOCs) were notably reduced or absent in the Δtps1 strain, while nerolidol, β-acorenol, and guaiene were particularly produced by the Otps1 strain. However, both the Δtps1 and Otps1 strains produced new terpene metabolites compared to the wild-type, which indicated that the tps1 gene played an important role in terpene synthesis but was not the only gene involved in T. atroviride HB20111. The TPS1 protein encoded by the tps1 gene could function as a sesquiterpene cyclase through biological information and evolutionary tree analysis. Additionally, fungal inhibition assay and wheat growth promotion assay results suggested that the deletion or overexpression of the tps1 gene had a minimal impact on fungal inhibitory activity, plant growth promotion, and development, as well as stress response. This implies that these activities of T. atroviride HB20111 might result from a combination of multiple metabolites rather than being solely dependent on one specific metabolite. This study offers theoretical guidance for future investigations into the mechanism of terpenoid synthesis and serves as a foundation for related studies on terpenoid metabolic pathways in fungi.

As one of the major abiotic stresses, salinity can affect crop growth and plant productivity worldwide. The inoculation of rhizosphere or endophytic microorganisms can enhance plant tolerance to salt stresses, but the potential mechanism is not clear. In this study, Trichoderma harzianum ST02 was applied on sweet sorghum [Sorghum bicolor (L.) Moench] in a field trial to investigate the effects on microbiome community and physiochemical properties in the rhizosphere soil. Compared with the non-inoculated control, Trichoderma inoculation significantly increased the stem yield, plant height, stem diameter, and total sugar content in stem by 35.52%, 32.68%, 32.09%, and 36.82%, respectively. In addition, Trichoderma inoculation improved the nutrient availability (e.g., N, P, and K) and organic matter in the rhizosphere soil and changed the bacterial community structure and function in both bulk and rhizosphere soil by particularly increasing the relative abundance of Actinobacter and N-cycling genes (nifH, archaeal and bacterial amoA). We proposed that T. harzianum ST02 could promote sweet sorghum growth under saline conditions by regulating available nutrients and the bacterial community in the rhizosphere soil.

Although soil and rhizosphere microbiomes in highly saline environments have been well-studied, the role of soil salinity in the ecological processes affecting endophyte colonization and persistence remain largely unclear in halophytic plants. The present study sampled young and mature plants of the halophyte Suaeda salsa from 42 sites in the Yellow River Delta, China that varied in soil salinity. Soil physicochemical properties, root and leaf microbiomes, phylogenetic variation among plant ecotypes, and leaf metabolites were analysed. In the roots of both young and mature plants, soil salinity significantly influenced the composition of the endophytic microbiota (r = 0.29 -0.45, P < 0.001), and negatively correlated with endophyte alpha-diversity (r =-0.75 --0.78,P < 0.001). Leaf microbiome dissimilarity increased with geographic distance (r = 0.17 -0.26, P < 0.001), based on distance-decay model, and was associated with plant phylogenetic variation (r = 0.15, P = 0.015 for young plants only). Additionally, leaf microbiome diversity and composition were correlated with soil age, pH, P content, and certain leaf metabolite compounds, but not with soil salinity. The dominant genera observed in young roots were Mesorhizobium spp. and Rhodomicrobium spp., while Pelagibius spp. was dominant in mature roots, and Pseudomonas spp. and Kushneria spp. were dominant in leaves. Soil salinity exerted a strong deter-ministic effect on the diversity and composition of the root endophyte community, while the acquisition and assembly of the leaf microbiome was affected by the dispersal effects, and the leaf metabolism of the host halophyte.

The infection of soil-borne diseases has the potential to modify root exudation and the rhizosphere microbiome. However, the extent to which these modifications occur in various monocropping histories remains inadequately explored. This study sampled healthy and diseased American ginseng (Panax quinquefolius L.) plants under 1-4 years of monocropping and analyzed the phenolic acids composition by HPLC, microbiome structure by high-throughput sequencing technique, and the abundance of pathogens by quantitative PCR. First, the fungal pathogens of Fusarium solani and Ilyonectria destructans in the rhizosphere soil were more abundant in the diseased plants than the healthy plants. The healthy American ginseng plants exudated more phenolic acid, especially p-coumaric acid, compared to the diseased plants after 1-2 years of monocropping, while this difference gradually diminished with the increase in monocropping years. The pathogen abundance was influenced by the exudation of phenolic acids, e.g., total phenolic acids (r = -0.455), p-coumaric acid (r = -0.465), and salicylic acid (r = -0.417), and the further in vitro test confirmed that increased concentration of p-coumaric acid inhibited the mycelial growth of the isolated pathogens for root rot. The healthy plants had a higher diversity of rhizosphere bacterial and fungal microbiome than the diseased plants only after a long period of monocropping. Our study has revealed that the cropping history of American ginseng has altered the effect of pathogens infection on rhizosphere microbiota and root exudation.

Arthrobacter ureafaciens DnL1-1 is a bacterium used for atrazine degradation, while Trichoderma harzianum LTR-2 is a widely used biocontrol fungus. In this study, a liquid co-cultivation of these two organisms was initially tested. The significant changes in the metabolome of fermentation liquors were investigated based on cultivation techniques (single-cultured and co-cultured DnL1-1 and LTR-2) using an UPLC-QTOF-MS in an untargeted metabolomic approach. Principle components analysis (PCA) and partial least squares discriminant analysis (PLS-DA) supervised modelling revealed modifications of the metabolic profiles in fermentation liquors as a function of interactions between different strains. Compared with pure-cultivation of DnL1-1, 51 compounds were altered during the cocultivation, with unique and significant differences in the abundance of organic nitrogen compounds (e.g. carnitine, acylcarnitine 4:0, acylcarnitine 5:0, 3-dehydroxycarnitine and O-acetyl-L-carnitine) and trans -zeatin riboside. Nevertheless, compared with pure-cultivation of LTR-2, the abundance of 157 compounds, including amino acids, soluble sugars, organic acids, indoles and derivatives, nucleosides, and others, changed significantly in the cocultivation. Among them, the concentration of tryptophan, which is a precursor to indoleacetic acid, indoleacetic acid, aspartic acid, and L-glutamic acid increased while that of most soluble sugars decreased upon cocultivation. The fermentation filtrates of co-cultivation of LTR-2 and DnL1-1 showed significant promoting effects on germination and radicle length of wheat. A subsequent experiment demonstrated synergistic effects of differential metabolites caused by co-cultivation of DnL1-1 and LTR-2 on wheat germination. Comprehensive metabolic profiling may provide valuable information on the effects of DnL1-1 and LTR-2 on wheat growth.

The root tip of a plant is highly sensitive to environmental cues and exerts sensory, chemical and movement responses and has even been likened to an animal’s brain. Yet, the assemblage of microbes at the root tip, the control of their diversity, the nature of their recruitment to that particular volume, and their roles in plant phenotypic function, remain poorly understood. This study investigated longitudinal niche differentiation of the root-associated microbiome in chickpeas ( Cicer arietinum L.) and its interactions with both diverse soil types and host plants with genetic variation in phenology, from the exterior to the interior of the root. Compared with late flowering (LF) genotypes, endophyte microbiomes at the apical zone of the early flowering (EF) host were characterised by greater diversity, higher compositional similarity to the basal zone, and closely inhabiting Rhizobacter and Methylotenera across soils. Additionally, EF genotypes secreted a specific composition of metabolites from the apical zone, with more carboxylates and amino acids (especially propionic acid and benzoic acid) than the LF plant. Our findings demonstrate that longitudinal differentiation within a seedling root is an essential feature shaping the root microbiome and indicative of genetic variation in phenology of host plants.

为探寻叶菜在连作障碍土壤中的安全生产措施,采用设施大棚小区试验,以土壤pH、土壤电导率、病害防效及增产率为评价指标,研究了土壤调理剂和木霉LTR-2联合施用对小油菜连作障碍土壤的修复作用,并根据土壤养分含量测定结果,进行了减肥试验.结果显示:经7500 kg/hm2土壤调理剂处理后,土壤pH由4.50升至6.95;土壤电导率由675.10μS/cm降至519.70μS/cm.施肥后与施肥前相比,B(土壤调理剂+有机肥I+复合肥)和C(土壤调理剂+有机肥I+LTR-2+复合肥)处理组中土壤pH均下降,土壤电导率均升高.经一茬种植后,与施肥后相比,收获时的pH分别从6.43和6.57降至6.06和6.26,土壤电导率由1011.43和959.47μS/cm降至955.70和863.43μS/cm;与常规处理A(有机肥II+复合肥)组相比,小油菜种植前后,B和C处理组中土壤pH和土壤电导率都存在显著差异;B和C处理组中根腐病防效分别为65.39％和80.77％;增产率分别为27.48％和33.59％.A、B、C三个处理速效养分在土壤中均有不同程度的过剩累积.与常规处理A'(有机肥III+复合肥)组相比,D'(有机肥I+LTR-2+1/3复合肥)处理组在减施复合肥66.67％的情况下,增产率为9.31％.

Fusarium crown rot and wheat sharp eyespot are major soil-borne diseases of wheat, causing serious losses to wheat yield in China. We applied high-throughput sequencing combined with qPCR to determine the effect of winter wheat seed dressing, with either Trichoderma atroviride HB20111 spore suspension or a chemical fungicide consisting of 6% tebuconazole, on the fungal community composition and absolute content of pathogens Fusarium pseudograminearum and Rhizoctonia cerealis in the rhizosphere at 180 days after planting. The results showed that the Trichoderma and chemical fungicide significantly reduced the amount of F. pseudograminearum in the rhizosphere soil ( p < 0.05), and also changed the composition and structure of the fungal community. In addition, field disease investigation and yield measurement showed that T. atroviride HB20111 treatment reduced the whiteheads with an average control effect of 60.1%, 14.9% higher than the chemical treatment; T. atroviride HB20111 increased yield by 7.7%, which was slightly more than the chemical treatment. Therefore, T. atroviride HB20111 was found to have the potential to replace chemical fungicides to control an extended range of soil-borne diseases of wheat and to improve wheat yield.