Investigating the synergistic antibacterial effects of chlorogenic and p-coumaric acids on Shigella dysenteriae.

Chlorogenic acid (CGA) is a well-known plant secondary metabolite exhibiting multiple physiological functions. The present study focused on screening for synergistic antibacterial combinations containing CGA. The combination of CGA and p-coumaric acid (pCA) exhibited remarkably enhanced antibacterial activity compared to that when administering the treatment only. Scanning electron microscopy revealed that a low-dose combination treatment could disrupt the Shigella dysenteriae cell membrane. A comprehensive analysis using nucleic acid and protein leakage assay, conductivity measurements, and biofilm formation inhibition experiments revealed that co-treatment increased the cell permeability and inhibited the biofilm formation substantially. Further, the polyacrylamide protein- and agarose gel-electrophoresis indicated that the proteins and DNA genome of Shigella dysenteriae severely degraded. Finally, the synergistic bactericidal effect was established for fresh-cut tomato preservation. This study demonstrates the remarkable potential of strategically selecting antibacterial agents with maximum synergistic effect and minimum dosage exhibiting excellent antibacterial activity in food preservation.

Effects of phosphorus-solubilizing bacteria and biochar application on phosphorus availability and tomato growth under phosphorus stress.

BACKGROUND: Phosphorus-solubilizing bacteria (PSB) are vital in converting insoluble phosphorus into a soluble form that plants can readily absorb and utilize in soil. While previous studies have mainly focused on the extracellular secretion of microorganisms, few have explored the intricate intracellular metabolic processes involved in PSB-mediated phosphorus solubilization. RESULTS: Here, we uncovered that Ca3(PO4)2 could serve as a source of insoluble phosphorus for the PSB, Pseudomonas sp. NK2. High-performance liquid chromatography (HPLC) results indicated higher levels of organic acids released from insoluble phosphorus compared to a soluble phosphorus source (KH2PO4), with acetic acid released exclusively under insoluble phosphorus condition. Moreover, non-target metabolomics was employed to delve into the intracellular metabolic profile. It unveiled that insoluble phosphorus significantly enhanced the tricarboxylic acid cycle, glycolysis, glyoxylic acid metabolism, and other pathways, leading to the production of acetic acid, gluconic acid, oxalic acid, and citric acid for insoluble phosphorus solubilization. In our quest to identify suitable biochar carriers, we assessed seven types of biochar through the conjoint analysis of NBRIP medium culture and application to soil for 30 days, with cotton straw-immobilized NK2 emerging as the most potent phosphorus content provider. Lastly, NK2 after cotton straw immobilization demonstrated the ability to enhance biomass, plant height, and root development of Solanum lycopersicum L. cv. Micro Tom. CONCLUSIONS: Pseudomonas sp. NK2 with cotton straw biochar could enhance phosphorus availability and tomato growth. These findings bear significant implications for the practical application of phosphorus-solubilizing bacteria in agricultural production and the promotion of environmentally sustainable farming practices.

Valorisation of tomato pomace in anti-pollution and microbiome-balance face cream.

Tomato pomace, the main by-product of tomato processing, is also an underestimated source of many active substances. This study aimed to determine the possibility of using oil obtained from tomato pomace in a face cream formulation. The bacterial community structure, face skin biophysical parameters and protection against air pollution were examined after daily application of the cosmetic by volunteers. In the tomato pomace oil, the profile of fatty acids was determined by GC‒MS, and the profile of volatile compounds was determined using the HS-SPME technique. The dominant bioactive component in the oil was linoleic acid (63.6%), and among the volatile compounds, it was carvotanacetone (25.8%). The application of the cream with tomato pomace oil resulted in an increase in the dominant genera Staphylococcus, Anaerococcus and Cutibacterium in the epibiome, particularly beneficial Staphylococcus epidermidis, while limiting the growth of the potentially opportunistic pathogens Kocuria spp., Micrococcus spp., Veillonella spp., and Rothia spp. This study showed the usefulness of tomato pomace oil as a natural ingredient in skin care cosmetics, reducing skin inflammation, sensitivity and melanin level, with potential protective effects against air pollution and microbiome-balance properties. Tomato pomace, which is commonly considered waste after tomato processing, can be used in the development of new cosmetics and may additionally contribute to reducing environmental nuisance.

The occurrence and mechanism of field resistance to boscalid and pyraclostrobin in Stemphylium solani, the causal agent of tomato gray leaf spot in China.

The destructive disease gray leaf spot, caused by Stemphylium solani, is prevalent in tomato plants in China. A variety of fungicides have been extensively used for controlling the disease, with a particular focus on succinate dehydrogenase inhibitors (SDHIs) and quinone outside inhibitors (QoIs). However, there was a lack of information regarding the resistance of S. solani to boscalid (SDHI) and pyraclostrobin (QoI) in China. In this study, the sensitivity of S. solani to boscalid and pyraclostrobin was monitored. The EC50 values for boscalid ranged from 0.02 to 3.0 µg∙mL-1, with an average value of 0.62 µg∙mL-1, while the EC50 values for pyraclostrobin ranged from 0.21 to 14.71 µg∙mL-1, with an average value of 6.03 µg∙mL-1. Based on these findings, the frequencies of observed resistance were as follows: 36.7% for boscalid and 50% for pyraclostrobin; while the resistance frequency to both boscalid and pyraclostrobin in S. solani was 19.4%. The mutation associated with boscalid resistance in S. solani within tomato fields was identified as SdhB-H277Y, while the mutation related to pyraclostrobin resistance was found in cytochrome b, specifically Cytb-G143A. The resistant mutants displayed diminished fitness in terms of mycelial growth, yet their pathogenicity exhibited no significant disparities. To delay the development of resistance, it is advisable to employ a rotation strategy using alternative fungicides with different modes of action or mix with fungicides with multi-site-contact activity for disease management.

Role of Enterococcus mundtii in gut of the tomato leaf miner (Tuta absoluta) to detoxification of Chlorantraniliprole.

Chlorantraniliprole (CAP) is applied worldwide for the control of caterpillars (Lepidoptera). However, with the overuse of CAP, the resistance problem in pest control is becoming increasingly serious. Recent studies have indicated a central role of the gut symbiont in insect pest resistance to pesticides and these may apply to the tomato leaf miner Tuta absoluta, is one of the most destructive insects worldwide. Here, we successfully isolated seven strains of tolerant CAP bacterium from the CAP-resistant T. absoluta gut, of which Enterococcus mundtii E14 showed the highest CAP tolerance, with a minimum inhibitory concentration (MIC) of 1.6 g/L and CAP degradation rate of 42.4%. Through transcriptomics and metabolism analysis, we studied the detoxification process of CAP by the E. mundtii E14, and found that CAP can be degraded by E. mundtii E14 into non-toxic compounds, such as 3,4-dihydroxy-2-(5-hydroxy-3,7-dimethylocta-2,6-dien-1-yl) benzoic acid and 2-pyridylacetic acid. Additionally, 2-pyridylacetic acid was detected both intracellular and extracellular in E. mundtii E14 treated with CAP. Meanwhile, we identified 52 up-regulated genes, including those associated with CAP degradation, such as RS11670 and RS19130. Transcriptome results annotated using KEGG indicated significant enrichment in up-regulated genes related to the glyoxylate cycle, nitrogen metabolism, and biosynthesis of secondary metabolites. Additionally, we observed that reinfection with E. mundtii E14 may effectively enhance resistance of T. absoluta to CAP. The LC50 values of the antibiotic treatment population of T. absoluta reinfection with E. mundtii E14 is 0.6122 mg/L, which was 18.27 folds higher than before reinfection. These findings offer new insights into T. absoluta resistance to CAP and contribute to a better understanding of the relationship between insecticide resistance and gut symbionts of T. absoluta, which may play a pivotal role in pest management.

Early and late blight disease identification in tomato plants using a neural network-based model to augmenting agricultural productivity.

Computer-advanced technologies have a significant impact across various fields. It is widely recognized that diseases have a detrimental effect on crop productivity and can significantly impact the economy, particularly in agricultural countries. Tomatoes hold great economic importance among cash crops, second only to potatoes. Globally, tomato production reaches a staggering 160 million tons annually, making it even more crucial for agricultural development. Unfortunately, the tomato crop is susceptible to several diseases, with early blight and late blight as two prominent culprits responsible for a production decrease of around 79%. Traditional disease detection and identification methods are time-consuming, expensive, and destructive, often requiring pathologists' expertise. Thus, the primary research objective is to enhance disease identification accuracy by leveraging deep learning techniques. A model based on the inception-V3 architecture has been devised to classify diseases affecting tomato plant leaves. The model was trained and tested using the PlantVillage dataset, which comprises 6000 sample images of tomato leaves. The training and testing process utilized an 80 : 20 ratio, resulting in an impressive classification accuracy of 97.44% for the proposed model. The proposed solution aims to enable the tomato industry to thrive in the global market by mitigating the impact of tomato leaf diseases. By reducing the prevalence of these diseases, the solution can increase demand and contribute to the industry's growth.

Rhizosphere microbiomes derived from vermicompost alter gene expression and regulatory pathways in tomato (Solanum lycopersicum, L.).

The gut microbiome of worms from composting facilities potentially harbors organisms that are beneficial to plant growth and development. In this experiment, we sought to examine the potential impacts of rhizosphere microbiomes derived from Eisenia fetida worm castings (i.e. vermicompost) on tomato (Solanum lycopersicum, L.) plant growth and physiology. Our experiment consisted of a greenhouse trial lasting 17 weeks total in which tomato plants were grown with one of three inoculant treatments: a microbial inoculant created from vermicompost (V), a microbial inoculant created from sterilized vermicompost (SV), and a no-compost control inoculant (C). We hypothesized that living microbiomes from the vermicompost inoculant treatment would enhance host plant growth and gene expression profiles compared to plants grown in sterile and control treatments. Our data showed that bacterial community composition was significantly altered in tomato rhizospheres, but fungal community composition was highly variable in each treatment. Plant phenotypes that were significantly enhanced in the vermicompost and sterile vermicompost treatments, compared to the control, included aboveground biomass and foliar δ15N nitrogen. RNA sequencing revealed distinct gene expression changes in the vermicompost treatment, including upregulation of nutrient transporter genes such as Solyc06g074995 (high affinity nitrate transporter), which exhibited a 250.2-fold increase in expression in the vermicompost treatment compared to both the sterile vermicompost and control treatments. The plant transcriptome data suggest that rhizosphere microbiomes derived from vermicompost can influence tomato gene expression and growth-related regulatory pathways, which highlights the value of RNA sequencing in uncovering molecular responses in plant microbiome studies.

Identification of hub genes and potential networks by centrality network analysis of PCR amplified Fusarium oxysporum f. sp. lycopersici EF1α gene.

BACKGROUND: Fusarium wilt is a devastating soil-borne fungal disease of tomato across the world. Conventional method of disease prevention including usage of common pesticides and methods like soil solarisation are usually ineffective in the treatment of this disease. Therefore, there is an urgent need to identify virulence related genes in the pathogen which can be targeted for fungicide development. RESULTS: Pathogenicity testing and phylogenetic classification of the pathogen used in this study confirmed it as Fusarium oxysporum f. sp. lycopersici (Fol) strain. A recent discovery indicates that EF1α, a protein with conserved structural similarity across several fungal genera, has a role in the pathogenicity of Magnaporthe oryzae, the rice blast fungus. Therefore, in this study we have done structural and functional classification of EF1α to understand its role in pathogenicity of Fol. The protein model of Fol EF1α was created using the template crystal structure of the yeast elongation factor complex EEF1A:EEF1BA which showed maximum similarity with the target protein. Using the STRING online database, the interactive information among the hub genes of EF1α was identified and the protein-protein interaction network was recognized using the Cytoscape software. On combining the results of functional analysis, MCODE, CytoNCA and CytoHubba 4 hub genes including Fol EF1α were selected for further investigation. The three interactors of Fol EF1α showed maximum similarity with homologous proteins found in Neurospora crassa complexed with the known fungicide, cycloheximide. Through the sequence similarity and PDB database analysis, homologs of Fol EF1α were found: EEF1A:EEF1BA in complex with GDPNP in yeast and EF1α in complex with GDP in Sulfolobus solfataricus. The STITCH database analysis suggested that EF1α and its other interacting partners interact with guanosine diphosphate (GDPNP) and guanosine triphosphate (GTP). CONCLUSIONS: Our study offers a framework for recognition of several hub genes network in Fusarium wilt that can be used as novel targets for fungicide development. The involvement of EF1α in nucleocytoplasmic transport pathway suggests that it plays role in GTP binding and thus apart from its use as a biomarker, it may be further exploited as an effective target for fungicide development. Since, the three other proteins that were found to be tightly associated Fol EF1α have shown maximum similarity with homologous proteins of Neurospora crassa that form complex with fungicide- Cycloheximide. Therefore, we suggest that cycloheximide can also be used against Fusarium wilt disease in tomato. The active site cavity of Fol EF1α can also be determined for computational screening of fungicides using the homologous proteins observed in yeast and Sulfolobus solfataricus. On this basis, we also suggest that the other closely associated genes that have been identified through STITCH analysis, they can also be targeted for fungicide development.

Metagenomic profiling of gut microbiota in Fall Armyworm (Spodoptera frugiperda) larvae fed on different host plants.

BACKGROUND: The fall armyworm (FAW, Spodoptera frugiperda) is a polyphagous pest known for causing significant crop damage. The gut microbiota plays a pivotal role in influencing the biology, physiology and adaptation of the host. However, understanding of the taxonomic composition and functional characteristics of the gut microbiota in FAW larvae fed on different host plants remains limited. METHODS: This study utilized metagenomic sequencing to explore the structure, function and antibiotic resistance genes (ARGs) of the gut microbiota in FAW larvae transferred from an artificial diet to four distinct host plants: maize, sorghum, tomato and pepper. RESULTS: The results demonstrated significant variations in gut microbiota structure among FAW larvae fed on different host plants. Firmicutes emerged as the dominant phylum, with Enterococcaceae as the dominant family and Enterococcus as the prominent genus. Notably, Enterococcus casseliflavus was frequently observed in the gut microbiota of FAW larvae across host plants. Metabolism pathways, particularly those related to carbohydrate and amino acid metabolism, played a crucial role in the adaptation of the FAW gut microbiota to different host plants. KEGG orthologs associated with the regulation of the peptide/nickel transport system permease protein in sorghum-fed larvae and the 6-phospho-ß-glucosidase gene linked to glycolysis/gluconeogenesis as well as starch and sucrose metabolism in pepper-fed larvae were identified. Moreover, the study identified the top 20 ARGs in the gut microbiota of FAW larvae fed on different host plants, with the maize-fed group exhibiting the highest abundance of vanRC. CONCLUSIONS: Our metagenomic sequencing study reveals significant variations in the gut microbiota composition and function of FAW larvae across diverse host plants. These findings underscore the intricate co-evolutionary relationship between hosts and their gut microbiota, suggesting that host transfer profoundly influences the gut microbiota and, consequently, the adaptability and pest management strategies for FAW.

Suprathreshold Water Spray Stimulus Enhances Plant Defenses against Biotic Stresses in Tomato.

Mechanical stimuli can affect plant growth, development, and defenses. The role of water spray stimulation, as a prevalent mechanical stimulus in the environment, in crop growth and defense cannot be overlooked. In this study, the effects of water spray on tomato plant growth and defense against the chewing herbivore Helicoverpa armigera and necrotrophic fungus Botrytis cinerea were investigated. Suprathreshold water spray stimulus (LS) was found to enhance tomato plant defenses against pests and pathogens while concurrently modifying plant architecture. The results of the phytohormone and chemical metabolite analysis revealed that LS improved the plant defense response via jasmonic acid (JA) signaling. LS significantly elevated the level of a pivotal defensive metabolite, chlorogenic acid, and reduced the emissions of volatile organic compounds (VOCs) from tomato plants, thereby defending against pest and pathogen attacks. The most obvious finding to emerge from this study is that LS enhances tomato plant defenses against biotic stresses, which will pave the way for further work on the application of mechanical stimuli for pest management.

Insect hypovirulence-associated mycovirus confers entomopathogenic fungi with enhanced resistance against phytopathogens.

Mycoviruses can alter the biological characteristics of host fungi, including change virulence or pathogenicity of phytopathogens and entomopathogenic fungi (EPF). However, most studies on the mycoviruses found in EPF have focused on the effects of the viruses on the virulence of host fungi towards insect pests, with relatively few reports on the effects to the host fungi with regard to plant disease resistance in hosts. The present study investigated the effects of the mycovirus Beauveria bassiana chrysovirus 2 (BbCV2) virus infection on host biological characteristics, evaluated antagonistic activity of BbCV2 against two phytopathogenic fungi (Sclerotinia sclerotiorum and Botrytis cinerea), and transcriptome analysis was used to reveal the interactions between viruses and hosts. Our results showed that BbCV2 virus infection increased B. bassiana's growth rate, spore production, and biomass, it also enhanced the capacity of host fungi and their metabolic products to inhibit phytopathogenic fungi. BbCV2 virus infection reduced the contents of the two pathogens in tomato plants significantly, and transcriptome analysis revealed that the genes related to competition for ecological niches and nutrition, mycoparasitism and secondary metabolites in B. bassiana were significantly up-regulated after viral infection. These findings indicated that the mycovirus infection is an important factor to enhance the ability of B. bassiana against plant disease after endophytic colonization. We suggest that mycovirus infection causes a positive effect on B. bassiana against phytopathogens, which should be considered as a potential strategy to promote the plant disease resistance of EPF.

Cross-family transfer of the Arabidopsis cell-surface immune receptor LORE to tomato confers sensing of 3-hydroxylated fatty acids and enhanced disease resistance.

Plant pathogens pose a high risk of yield losses and threaten food security. Technological and scientific advances have improved our understanding of the molecular processes underlying host-pathogen interactions, which paves the way for new strategies in crop disease management beyond the limits of conventional breeding. Cross-family transfer of immune receptor genes is one such strategy that takes advantage of common plant immune signalling pathways to improve disease resistance in crops. Sensing of microbe- or host damage-associated molecular patterns (MAMPs/DAMPs) by plasma membrane-resident pattern recognition receptors (PRR) activates pattern-triggered immunity (PTI) and restricts the spread of a broad spectrum of pathogens in the host plant. In the model plant Arabidopsis thaliana, the S-domain receptor-like kinase LIPOOLIGOSACCHARIDE-SPECIFIC REDUCED ELICITATION (AtLORE, SD1-29) functions as a PRR, which senses medium-chain-length 3-hydroxylated fatty acids (mc-3-OH-FAs), such as 3-OH-C10:0, and 3-hydroxyalkanoates (HAAs) of microbial origin to activate PTI. In this study, we show that ectopic expression of the Brassicaceae-specific PRR AtLORE in the solanaceous crop species Solanum lycopersicum leads to the gain of 3-OH-C10:0 immune sensing without altering plant development. AtLORE-transgenic tomato shows enhanced resistance against Pseudomonas syringae pv. tomato DC3000 and Alternaria solani NL03003. Applying 3-OH-C10:0 to the soil before infection induces resistance against the oomycete pathogen Phytophthora infestans Pi100 and further enhances resistance to A. solani NL03003. Our study proposes a potential application of AtLORE-transgenic crop plants and mc-3-OH-FAs as resistance-inducing biostimulants in disease management.

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

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

Impact of pre-harvest fungicide application on the storage performance of tomato fruits.

To examine the impact of pre-harvest fungicide applications on the postharvest storage performance of tomato fruits, we measured the lycopene content, hardness, soluble solids content, rotting rate, and weight loss rate of the fruits, as well as conducted a sensory assessment. Protective and systematic fungicides were sprayed on tomatoes 20 days before harvest in order to prevent rotting and weight loss during storage. Our findings showed that, the fungicide-treated tomatoes had a significantly lower rotting rate of 16.00% and a weight loss rate of 3.96%. However the control group experienced 65.33% rotting rate and 6.90% weight loss rate on 12th days of storage. Out of the pre-harvest applications, 'Zineb' a protective fungicide significantly delayed the loss of hardness and soluble solids accumulation in tomato fruits during storage, but it had no significant effect on lycopene content. On the other hand, when comparing to the examined treatment, the systemic fungicides did not have any significant effect on the postharvest storage performance of tomato fruits. Sensory evaluation results indicated that systemic fungicides improved the aroma of the fruits, while protective fungicides had a greater impact on the appearance and juiciness of the fruits. This study offers a potential novel solution for preserving fruits and vegetables which have been frequently infected by phytopathogens during storage, and consequently mitigate/reduce postharvest losses.

Less is more: CRISPR/Cas9-based mutations in DND1 gene enhance tomato resistance to powdery mildew with low fitness costs.

Powdery mildew (PM), triggered by Oidium neolycopersici, represents a significant threat and a major concern for the productivity of tomato plants (Solanum lycopersicum L.). The presence of susceptibility (S) genes in plants facilitates pathogen proliferation and their dysfunction can lead to a recessively inherited broad-spectrum and durable type of resistance. Past studies have demonstrated that disrupting the function of DND1 (Defense No Death 1) increases plant resilience against various pathogens, such as powdery mildew (PM), but this comes at the cost of negatively affecting the overall health and vigor of the plant. To investigate the possibility of minimizing the adverse effects of the dnd1 mutation while boosting disease resistance, a CRISPR-Cas9 construct with four single guide RNAs targeting three exons of SlDND1 (Solyc02g088560.4.1) was designed and introduced into the tomato variety Moneymaker (MM) through Agrobacterium tumefaciens-mediated transformation. Three T1 lines (named E1, E3 and E4) were crossed with MM and then selfed to produce TF2 families. All the TF2 plants in homozygous state dnd1/dnd1, showed reduced PM symptoms compared to the heterozygous (DND1/dnd1) and wild type (DND1/DND1) ones. Two full knock-out (KO) mutant events (E1 and E4) encoding truncated DND1 proteins, exhibited clear dwarfness and auto-necrosis phenotypes, while mutant event E3 harbouring deletions of 3 amino acids, showed normal growth in height with less auto-necrotic spots. Analysis of the 3D structures of both the reference and the mutant proteins revealed significant conformational alterations in the protein derived from E3, potentially impacting its function. A dnd1/dnd1 TF2 line (TV181848-9, E3) underwent whole-genome sequencing using Illumina technology, which confirmed the absence of off-target mutations in selected genomic areas. Additionally, no traces of the Cas9 gene were detected, indicating its elimination through segregation. Our findings confirm the role of DND1 as an S-gene in tomato because impairment of this gene leads to a notable reduction in susceptibility to O. neolycopersici. Moreover, we provide, for the first time, a dnd1 mutant allele (E3) that exhibits fitness advantages in comparison with previously reported dnd1 mutant alleles, indicating a possible way to breed with dnd1 mutants.

Carbon Source and Substrate Surface Affect Biofilm Formation by the Plant-Associated Bacterium Pseudomonas donghuensis P482.

The ability of bacteria to colonize diverse environmental niches is often linked to their competence in biofilm formation. It depends on the individual characteristics of a strain, the nature of the colonized surface (abiotic or biotic), or the availability of certain nutrients. Pseudomonas donghuensis P482 efficiently colonizes the rhizosphere of various plant hosts, but a connection between plant tissue colonization and the biofilm formation ability of this strain has not yet been established. We demonstrate here that the potential of P482 to form biofilms on abiotic surfaces and the structural characteristics of the biofilm are influenced by the carbon source available to the bacterium, with glycerol promoting the process. Also, the type of substratum, polystyrene or glass, impacts the ability of P482 to attach to the surface. Moreover, P482 mutants in genes associated with motility or chemotaxis, the synthesis of polysaccharides, and encoding proteases or regulatory factors, which affect biofilm formation on glass, were fully capable of colonizing the root tissue of both tomato and maize hosts. Investigating the role of cellular factors in biofilm formation using these plant-associated bacteria shows that the ability of bacteria to form biofilm on abiotic surfaces does not necessarily mirror its ability to colonize plant tissues. Our research provides a broader perspective on the adaptation of these bacteria to various environments.

Lignin/Surfactin Coacervate as an Eco-Friendly Pesticide Carrier and Antifungal Agent against Phytopathogen.

Excessive usage of biologically toxic fungicides and their matrix materials poses a serious threat to public health. Leveraging fungicide carriers with inherent pathogen inhibition properties is highly promising for enhancing fungicide efficacy and reducing required dosage. Herein, a series of coacervates have been crafted with lignin and surfactin, both of which are naturally derived and demonstrate substantial antifungal properties. This hierarchically assembled carrier not only effectively loads fungicides with a maximum encapsulation efficiency of 95% but also stably deposits on hydrophobic leaves for high-speed impacting droplets. Intriguingly, these coacervates exhibit broad spectrum fungicidal activity against eight ubiquitous phytopathogens and even act as a standalone biofungicide to replace fungicides. This performance can significantly reduce the fungicide usage and be further strengthened by an encapsulated fungicide. The inhibition rate reaches 87.0% when 0.30 mM pyraclostrobin (Pyr) is encapsulated within this coacervate, comparable to the effectiveness of 0.80 mM Pyr alone. Additionally, the preventive effects against tomato gray mold reached 53%, significantly surpassing those of commercial adjuvants. Thus, it demonstrates that utilizing biosurfactants and biomass with intrinsic antifungal activity to fabricate fully biobased coacervates can synergistically combine the functions of a fungicide carrier and antifungal agent against phytopathogens and guarantee environmental friendliness. This pioneering approach provides deeper insights into synergistically enhancing the effectiveness of agrochemicals from multiple aspects, including fungicide encapsulation, cooperative antifungal action, and droplet deposition.

Comparative Genomics Screens Identify a Novel Small Secretory Peptide, SlSolP12, which Activates Both Local and Systemic Immune Response in Tomatoes and Exhibits Broad-Spectrum Activity.

Small secreted peptides (SSPs) are essential for defense mechanisms in plant-microbe interactions, acting as danger-associated molecular patterns (DAMPs). Despite the first discovery of SSPs over three decades ago, only a limited number of SSP families, particularly within Solanaceae plants, have been identified due to inefficient approaches. This study employed comparative genomics screens with Solanaceae proteomes (tomato, tobacco, and pepper) to discover a novel SSP family, SolP. Bioinformatics analysis suggests that SolP may serve as an endogenous signal initiating the plant PTI response. Interestingly, SolP family members from tomato, tobacco, and pepper share an identical sequence (VTSNALALVNRFAD), named SlSolP12 (also referred to as NtSolP15 or CaSolP1). Biochemical and phenotypic analyses revealed that synthetic SlSolP12 peptide triggers multiple defense responses: ROS burst, MAPK activation, callose deposition, stomatal closure, and expression of immune defense genes. Furthermore, SlSolP12 enhances systemic resistance against Botrytis cinerea infection in tomato plants and interferes with classical peptides, flg22 and Systemin, which modulate the immune response. Remarkably, SolP12 activates ROS in diverse plant species, such as Arabidopsis thaliana, soybean, and rice, showing a broad spectrum of biological activities. This study provides valuable approaches for identifying endogenous SSPs and highlights SlSolP12 as a novel DAMP that could serve as a useful target for crop protection.

Phytotoxic Isocassadiene-Type Diterpenoids from Tomato Fusarium Crown and Root Rot Pathogen Fusarium oxysporum f. sp. radicis-lycopersici.

Fusarium crown and root rot (FCRR) has emerged as a highly destructive soil-borne disease, posing a significant threat to the safe cultivation of tomatoes in recent years. The pathogen of tomato FCRR is Fusarium oxysporum f. sp. radicis-lycopersici (Forl). To explore potential phytotoxins from Forl, eight undescribed diterpenoids namely fusariumic acids A-H (1-8) were isolated. Their structures were elucidated by using spectroscopic data analyses, quantum chemical calculations, and X-ray crystallography. Fusariumic acids A (1) and C-H (3-8) were typical isocassadiene-type diterpenoids, while fusariumic acid B (2) contained a cage-like structure with an unusual 7,8-seco-isocassadiene skeleton. A biosynthetic pathway of 2 was proposed. Fusariumic acids A (1) and C-H (3-8) were further assessed for their phytotoxic effects on tomato seedlings at 200 µg/mL. Among them, fusariumic acid F (6) exhibited the strongest inhibition against the hypocotyl and root elongation of tomato seedlings, with inhibitory rates of 61.3 and 45.3%, respectively.

Exploring the effects of entomopathogenic nematode symbiotic bacteria and their cell free filtrates on the tomato leafminer Tuta absoluta and its predator Nesidiocoris tenuis.

The use of biocontrol agents, such as predators and entomopathogenic nematodes, is a promising approach for the effective control of the tomato leafminer Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidaean), an oligophagous insect feeding mainly on Solanaceae species and a major pest of field- and greenhouse-grown tomatoes globally. In this context, the effects of two entomopathogenic nematode species Steinernema carpocapsae (Weiser) (Rhabditida: Steinernematidae) and Heterorhabditis bacteriophora (Poinar) (Rhabditida: Heterorhabditidae), as well as their respective bacterial symbionts, Xenorhabdus nematophila and Photorhabdus luminescens (Enterobacterales: Morganelaceae), which were applied as bacterial cell suspensions and as crude cell-free liquid filtrates on T. absoluta larvae, were investigated. The results showed that of all treatments, the nematodes S. carpocapsae and H. bacteriophora were the most effective, causing up to 98 % mortality of T. absoluta larvae. Regarding bacteria and their filtrates, the bacterium X. nematophila was the most effective (69 % mortality in young larvae), while P. luminescens and both bacterial filtrates showed similar potency (ca. 48-55 % mortality in young larvae). To achieve a holistic approach of controlling this important pest, the impact of these factors on the beneficial predator Nesidiocoris tenuis (Reuter) (Hemiptera: Miridae) was also studied. The results demonstrated that although nematodes and especially S. carpocapsae, caused significant mortality on N. tenuis (87 %), the bacterial cell suspensions of X. nematophila and P. luminescens and crude cell-free liquid filtrates had minimum impact on this beneficial predator (∼11-30 % mortality).