Induced Plant Resistance Research Articles

Molecular interactions of Trichoderma: from microbial competition to soil health promotion

The increasing demand for sustainable solutions to agricultural pest and disease management has positioned Trichoderma fungi as a promising biological control agent. Trichoderma is not only capable of suppressing various plant pathogens but also promotes plant growth and strengthens natural plant defenses. This mini-review explores the molecular mechanisms underlying Trichoderma's ability to function as a biocontrol agent, focusing on nutrient competition, antibiotic production, mycoparasitism, and the induction of plant resistance. Additionally, advances in genomics and transcriptomics have facilitated a deeper understanding of the signaling pathways and genes responsible for Trichoderma's biocontrol effectiveness, including G-protein and MAPK pathways. Beyond pathogen suppression, Trichoderma plays a key role in enhancing soil health and establishing symbiotic relationships with plants, contributing to improved nutrient absorption and growth hormone production. However, challenges remain in translating laboratory success to large-scale field applications. This mini review highlights the need for further research on optimizing Trichoderma formulations, understanding its interaction with other beneficial soil organisms, and exploring genetic engineering to enhance its biocontrol capabilities. The future of Trichoderma lies in its integration into holistic, agroecological systems alongside other sustainable pest management strategies.

Interspecific Allelopathic Interaction Primes Direct and Indirect Resistance of Neighbor Plant in Agroforestry System

Agroforestry system with high biodiversity augments ecosystem stability and minimizes its vulnerability to environmental disturbances and disease. Deciphering the underlying mechanisms of interspecies allelopathic interactions in disease suppression in agroforestry offer a sustainable strategy for plant disease management. Here, we utilized Panax ginseng cultivated under Pinus koraiensis forests, where the occurrences of Alternaria leaf spot are low, as a research model to investigate the role of allelochemicals in disease suppression. Our findings demonstrate that foliar application of leachates from the needles of P. koraiensis effectively enhanced the resistance of P. ginseng against Alternaria leaf spot. Through GC-MS analysis, we identified and quantified endo-borneol as a key compound in the leachates of P. koraiensis, and validated its capacity to prime resistance in its neighbor P. ginseng. We discovered that endo-borneol not only directly activates defense-related pathways of P. ginseng to induce resistance, but also indirectly recruits its rhizospheric beneficial microbiota by enhancing the secretion of ginsenosides, thereby triggering induced systemic resistance (ISR). Importantly, the higher concentrations of endo-borneol from 10 to 100 mg/L demonstrated a stronger capacity to induce plant resistance and enhance root secretion to recruit more microbiota compared with the lower concentrations from 0.01 to 1 mg/L. Moreover, endo-borneol exhibited antifungal activity against the growth of the pathogen Alternaria panax when its concentrations exceeding 10 mg/L. These results reveal the multifaceted functions of allelochemical endo-borneol in disease suppression in agroforestry system and highlight its potential as an environmental-friendly compound for sustainable agriculture.

Synergistic Effect of Two Peptaibols from Biocontrol Fungus Trichoderma longibrachiatum Strain 40418 on CO-Induced Plant Resistance.

Trichoderma longibrachiatum is a filamentous fungus used as a biological control agent against different plant diseases. The multifunctional secondary metabolites synthesized by Trichoderma, called peptaibols, have emerged as key elicitors in plant innate immunity. This study obtained a high-quality genome sequence for the T. longibrachiatum strain 40418 and identified two peptaibol biosynthetic gene clusters using knockout techniques. The two gene cluster products were confirmed as trilongin AIV a (11-residue) and trilongin BI (20-residue) using liquid chromatography coupled with tandem mass spectrometry. Further investigations revealed that these peptaibols induce plant resistance to Pseudomonas syringae pv tomato (Pst) DC3000 infection while triggering plant immunity and cell death. Notably, the two peptaibols exhibit synergistic effects in plant-microbe signaling interactions, with trilongin BI having a predominant role. Moreover, the induction of tomato resistance against Meloidogyne incognita showed similarly promising results.

Exploiting Induced Plant Resistance for Sustainable Pest Management: Mechanisms, Elicitors, and Applications: A Review

Plants and phytophagous (plant-eating) arthropods have coevolved over millions of years, leading to the development of both constitutive and inducible defense mechanisms in plants. Despite this long history of coexistence, it remains unclear how to precisely regulate each host-arthropod interaction to achieve an equilibrium that maximizes crop yield. The defensive chemicals produced by plants can significantly affect herbivores’ feeding behaviour, growth, and survival. These chemicals may be generated constitutively (continuously) or induced in response to herbivore damage. Induced resistance, a strategy where plants enhance their defences after being attacked, holds potential for reducing the number of insecticides needed in pest management. Chemical elicitors, which trigger the production of secondary metabolites that confer resistance to insects, can be used to manipulate host plant resistance, specifically by inducing resistance. By understanding the mechanisms underlying induced resistance, it is possible to predict which herbivores will be impacted by these responses. Applying induced response elicitors to crop plants can strengthen their natural defences against herbivore damage. Additionally, it is possible to genetically modify plants so that they constitutively produce defense chemicals, providing continuous protection in areas where herbivory is a constant threat. As part of integrated pest management, induced resistance can be used to develop crop cultivars that readily trigger an inducible response in the event of a mild infestation, contributing to sustainable agricultural practices and reducing reliance on chemical pesticides.

Effect of <i>Bacillus subtilis</i> in combination with chitosan salicylate on peroxidase and catalase activity in <i>B. sorokiniana</i> infected wheat

The aim of the work was to study the effect of Bacillus subtilis strains VKM B‑2604D and VKM B‑2605D which form the basis of the Vitaplan biological product, and their combinations with chitosan salicylate on antioxidant defense enzymes in the process of formation of resistance of wheat plants to infection with the dark brown blotch pathogen Bipolaris sorokiniana. In wheat plants treated with B. subtilis strains and their combinations with chitosan salicylate, upon subsequent infection, catalase and peroxidase are activated, which regulate the intensity of oxidative stress induced by the introduction of the pathogen. Taking into account the data obtained by us, it can be assumed that the increase in plant resistance to the pathogen is realized through the control of the activity of antioxidant enzymes (inparticular, catalase, peroxidase), which maintain the concentration of H2O2 at the level necessary for the neutralization of the phytopathogen in tissues, including the direct destruction of the invading pathogen and / or activation of crosslinking and lignification of the cell wall. These processes strengthen the cell wall and help contain the spread of the pathogen in the plant. At the same time, protective reactions are also switched on, leading to the development of induced resistance in wheat plants to dark brown spotting, which manifests itself in a decrease in the development of the disease by 25–45% relative to the infected control in the treated plants. The obtained results indicate that the combination of active strains of microorganisms-antagonists of plant pathogens and chitosan salicylate is promising for increasing the biological efficiency and expanding the spectrum of action of the developed prescription forms of biological products.

Evaluation of Resistance Induction Promoted by Bioactive Compounds of Pseudomonas aeruginosa LV Strain against Asian Soybean Rust.

Pseudomonas are known as higher producers of secondary metabolites with antimicrobial properties and plant growth promoters, including resistance induction. These mechanisms should be an alternative to pesticide use in crop production. Phakopsora pachyrhizi causes Asian soybean rust, representing a high loss of yield around the world. The objective of this paper was to evaluate the application of secondary metabolites produced by Pseudomonas aeruginosa LV strain from the semi-purified fraction F4A in soybean plants to induce plant resistance against P. pachyrhizi in field conditions. The experimental design was performed in randomized blocks with three replicates using two F4A doses (1 and 10 μg mL-1) combined or not with fungicides (Unizeb Gold® or Sphere Max®). The control treatment, with Uni + Sph, saponins, flavonoids, and sphingolipids, showed higher intensities in the plants. In contrast, plants treated with the F4A fraction mainly exhibited fatty acid derivatives and some non-identified compounds with nitrogen. Plants treated with Sphere Max®, with or without F4A10, showed higher intensities of glycosylated flavonoids, such as kaempferol, luteolin, narigenin, and apigenin. Plants treated with F4A showed higher intensities of genistein and fatty acid derivatives. These increases in flavonoid compound biosynthesis and antioxidant properties probably contribute to the protection against reactive oxygen species (ROS).

Bacillus velezensis HN-2: a potent antiviral agent against pepper veinal mottle virus.

Pepper veinal mottle virus (PVMV) belongs to the genus Potyvirus within the family Potyviridae and is a major threat to pepper production, causing reduction in yield and fruit quality; however, efficient pesticides and chemical treatments for plant protection against viral infections are lacking. Hence, there is a critical need to discover highly active and environment-friendly antiviral agents derived from natural sources. Bacillus spp. are widely utilized as biocontrol agents to manage fungal, bacterial, and viral plant diseases. Particularly, Bacillus velezensis HN-2 exhibits a strong antibiotic activity against plant pathogens and can also induce plant resistance. The experimental subjects employed in this study were Bacillus velezensis HN-2, benzothiadiazole, and dufulin, aiming to evaluate their impact on antioxidant activity, levels of reactive oxygen species, activity of defense enzymes, and expression of defense-related genes in Nicotiana benthamiana. Furthermore, the colonization ability of Bacillus velezensis HN-2 in Capsicum chinense was investigated. The results of bioassays revealed the robust colonization capability of Bacillus velezensis HN-2, particularly in intercellular spaces, leading to delayed infection and enhanced protection against PVMV through multiple plant defense mechanisms, thereby promoting plant growth. Furthermore, Bacillus velezensis HN-2 increased the activities of antioxidant enzymes, thereby mitigating the PVMV-induced ROS production in Nicotiana benthamiana. Moreover, the application of Bacillus velezensis HN-2 at 5 dpi significantly increased the expression of JA-responsive genes, whereas the expression of salicylic acid-responsive genes remained unchanged, implying the activation of the JA signaling pathway as a crucial mechanism underlying Bacillus velezensis HN-2-induced anti-PVMV activity. Immunoblot analysis revealed that HN-2 treatment delayed PVMV infection at 15 dpi, further highlighting its role in inducing plant resistance and promoting growth and development. These findings underscore the potential of Bacillus velezensis HN-2 for field application in managing viral plant diseases effectively.

Morinda citrifolia Essential Oil: A Plant Resistance Biostimulant and a Sustainable Alternative for Controlling Phytopathogens and Insect Pests.

With the growing demand for sustainable and safe agricultural practices, plant compounds emerge as a solution for biological activities. Here, we evaluated the potential of using Morinda citrifolia essential oil to induce plant resistance and to control phytopathogens (Curvularia lunata) and insect pests (Daubulus maidis). We conducted a chromatographic analysis to unveil the essential oil components. We also quantified the activity levels of antioxidant enzymes and chitinase for resistance induction. The antifungal action was evaluated through disease progression and the inhibition of mycelial growth in addition to in silico studies that made it possible to predict the interaction site between the fungal protein and the compounds. We assessed the toxicity and repellent actions towards the D. maidis. Octanoic acid (58.43%) was identified as the essential oil major compound. Preventive treatment with essential oil and octanoic acid (25.0 µL mL-1) increased not only the plant defense activities (i.e., the activity of the enzymes superoxide dismutase, catalase, phenol peroxidase, ascorbate peroxidase, and chitinase) but also controlled Curvularia leaf spot. The stable interactions between octanoic acid and tyrosine-tRNA ligase from C. lunata suggested protein synthesis inactivation. The essential oil inhibited 51.6% of mycelial growth, and this effect was increased to 75.9% with the addition of adjuvants (i.e., angico gum). The essential oil reduced 76% of the population of D. maidis adults and repelled 50% of the number of D. maidis after 48 h under field conditions. The repellency effect in the field reduced the population of D. maidis adults, transmitters of the stunting complex, by 50%. The results highlight the potential of M. citrifolia as a resistance activator, fungicide, insecticide, and an effective biorational alternative.

Biosynthesis of cupric oxide nanoparticles: its antiviral activities against TMV by directly destroying virion and inducing plant resistance

Tobacco mosaic virus (TMV) is widely recognized as one of the most important plant viruses, causing significant agricultural losses in terms of both quality and yield worldwide each year. This study demonstrated the biosynthesis of copper oxide nanoparticles (CuONPs) using orange peel extract for effective control of TMV infection both in vitro and in vivo. After treatment with CuONPs (100 mg/L) for 2 h, TMV particles exhibited evident fragmentation in vitro, reducing infectivity on tobacco plants. Similarly, the application of CuONPs on Nicotiana benthamiana (N. benthamiana) positively impeded viral replication and accumulation in vivo. Interestingly, the expression of systemic resistance-related genes (PR1, PR2, ERF1, and JAZ3) in the host plant was up-regulated by CuONPs treatment, supporting that CuONPs activated plant immunity to inhibit TMV. Importantly, the application of CuONPs (100 mg/L) did not exhibit any toxic effects on tobacco and, instead, resulted in the promotion of chlorophyll content, as well as an increase in the fresh weight and dry weight of the plant when compared to the control treatment. Overall, we proposed that the appropriate concentration of CuONPs (100 mg/L) can directly break viral particles by passivating, boost plant immunity by stimulating systemic acquired resistance (SAR), and provide nutritional supplements to promote plant growth.

Fermentation optimization and metabolomic analysis of a Bacillus subtilis co-culture system for fengycin production from mixed sugars

Fengycin is a cyclic lipopeptide with multiple effects, including cell membrane disruption, induction of systemic resistance in plants, and plant growth promotion. This study used a co-culture system to produce fengycin in a sugar mixture fermentation medium simulating lignocellulosic hydrolysate. First, we compared the fengycin production profiles of the pure cultures and co-culture of three Bacillus subtilis, 168DSABA1, BSP003, and BSJ0232, in a sugar mixture fermentation medium. The co-culture system was then optimized (relative inoculation ratio, ratio of glucose to xylose in the sugar mixture, fermentation time, total carbon source concentration and tryptone concentration) using response surface methodology (RSM) based on single-factor experiments, which increased the fengycin titer of the co-culture system from 241.7 ± 12.0–575.5 ± 5.8 mg/L. Finally, metabolomics was used to analyze the reasons for the increase of fengycin production and the deficiencies of the system: Based on this a co-culture system containing four Bacillus subtilis (4BS) and a co-culture system containing five Bacillus subtilis (5BS) were constructed, which further increased the titer of fengycin to 650.2 ± 9.6 mg/L and 2396 ± 42 mg/L, respectively. The present study provides a reference or improving the industrial production of fengycin and the utilization of lignocellulosic hydrolysates.

PHYLOGENETIC CONNECTIONS AND COMPARISONS OF THE AMINO ACID SEQUENCES OF SEVERAL PEPTIDE INDUCERS OF MICROBIAL ORIGIN- A FOUNDATION STUDY FOR DEVELOPMENT OF NOVEL BIOPESTICIDES

Peptides of microbial origin stand out as one of theprominent tools to elicit plant immunity. These peptides comprise one of thekey strategies of integrated pest management and are considered as candidatesto develop novel biopesticides. Manyresearch investigations have proved their potential in fending off plantpathogens and were described as sustainable plant protection strategies. Thepresent study was attempted to discover phylogenetic relationships and compareamino acid sequence alignments of various peptide elicitors of microbialorigin. Phylogenetic analysis of 33 microbial peptide elicitors resulted in twoclusters, one cluster contained 19 flagellin sequences, which is furtherdivided into one major (15 peptide sequences) and one (4 peptide sequences)minor subclusters. Further amino acid sequence alignments were carried outbased on the evolutionary relationships among the peptides. The amino acidsequence alignment of flagellin sequences using Clustal W did not present conservativeamino acid sequences except Serine (S), Alanine (A) and Aspartic acid (D).These conserved amino acids (SAxD) that are positioned in the protruding loopmay play a vital role in recognition by plant surface receptors. Alignment ofamino acid sequences of cold shock protein, xylanase, elongation factor andharpin from various sources did not present conservative amino acid sequencesexcept glycine. These investigations lay a theoretical foundation for exploringmany more microbial peptides for inducing plant resistance.

Monitoring of main tomato (Solánum lycopérsicum L.) diseases and methods of microbiological control of phytopathogens

The article highlights the main diseases of tomato plants caused by phytopathogenic microorganisms that cause great damage in many countries of the world, including Ukraine. It has been analyzed that phytopathogenic micromycetes that parasitize tomato plants cause huge losses in agricultural production, reducing the quality of products, and also release toxins that cause poisoning and numerous serious diseases that affect humans and animals that consume this product. It has been established that the most common tomato diseases caused by phytopathogenic fungi are late blight, alternaria, septoria, gray rot, spotted wilt virus, and bacterial tomato cancer. Microbiological means of control were analyzed as an alternative to chemical fungicides, which are considered safe methods in modern agriculture. They stimulate the defense mechanisms of plants, acting as inducers of plant resistance or as means of biological control. It was found that one of the common biological preparations in the fight against diseases and improving the growth of tomato culture are preparations containing Trichoderma spp. They are widely used as biofungicides against the pathogens Botrytis cinerea, Fusarium oxysporum, Rhizoctonia solani and Sclerotium rolfsii. The study of Mexican scientists on the testing of various isolates of the genus Trichoderma spp. Chinese scientists identified a strain of Pseudomonas aeruginosa (CQ-4) that can effectively control the spread of gray rot disease and identified bacteria of the genus Bacillus subtilis, which are characterized by notable antagonistic activity against a wide range of phytopathogenic bacteria and micromycetes and are a factor in biological control. Also, scientists from Egypt who conducted experiments on two endophytic fungi, namely Curvularia lunata and Nigrospora sphaerica, where their antagonistic action against phytopathogenic fungi and their ability to produce an important growth hormone and provide some necessary nutrients for plant growth were evaluated. A number of investigated antagonist strains are the basis or promising for the production of microbial preparations for controlling phytopathogens in agroecosystems and increasing the yield of tomato plants.

Serratia plymuthica HK9-3 enhances tomato resistance against Phytophthora capsici by modulating antioxidant defense systems and rhizosphere micro-ecological condition.

Tomatoes are frequently challenged by various pathogens, among which Phytophthora capsici (P. capsici) is a destructive soil-borne pathogen that seriously threatens the safe production of tomatoes. Plant growth-promoting rhizobacteria (PGPR) positively induced plant resistance against multiple pathogens. However, little is known about the role and regulatory mechanism of PGPR in tomato resistance to P. capsici. Here, we identified a new strain Serratia plymuthica (S. plymuthica), HK9-3, which has a significant antibacterial effect on P. capsici infection. Meanwhile, stable colonization in roots by HK9-3, even under P. capsici infection, improved tomato growth parameters, root system architecture, photosynthetic capacity, and boosted biomass. Importantly, HK9-3 colonization significantly alleviated the damage caused by P. capsici infection through enhancing ROS scavenger ability and inducing antioxidant defense system and pathogenesis-related (PR) proteins in leaves, as evidenced by elevating the activities of peroxidase (POD), superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), phenylalanine ammonia lyase (PAL), polyphenol oxidase (PPO), and chitinase, β-1,3-glucanase, and increasing the transcripts of POD, SOD, CAT, APX1, PAL1, PAL2, PAL5, PPO2, CHI17 and β-1,3-glucanase genes. Notably, HK9-3 colonization not only effectively improved soil microecology and soil fertility, but also significantly enhanced fruit yield by 44.6% and improved quality. Our study presents HK9-3 as a promising and effective solution for controlling P. capsici infection in tomato cultivation while simultaneously promoting plant growth and increasing yield, which may have implications for P. capsici control in vegetable production.

Response of mineral formulation towards different growth phases of arabica coffee in lowland

Arabica coffee cultivation is limited by altitude, which affects its production. Some farmers in Jember Regency are innovating to grow arabica coffee in the lowland, but the potential for leaf rust disease is quite high. Plant natural resistance can be enhanced by adding minerals formulation (containing silica, iodine, and calcium). This research aimed to determine which phase is more effective for applying mineral formulation that induces plant resistance. The formulation was tested on arabica coffee plants grown at the lowland (460 masl) in Jember Regency on 12 years old (y.o) mature and 1 y.o immature plants. One formulation was dissolved in 14 L of water and applied by foliar feeding. The effect was analyzed using two-way T-test of two samples assuming unequal variances at 95% confidence level to determine the differences. The analysis showed that the plants supplemented with the formulation could increase the variables that supported the natural resistance of plants (both mechanically and through the production of chemical compounds), such as polyphenol content, flavonoids, antioxidant activity, total dissolved protein, vitamin C, reducing sugar, lignin, cellulose, hemicellulose, and iodine content in the plant. The response of the formulation application showed that the most resistance variables was better in 1 y.o immature plants than in 12 y.o mature plants. The application of mineral formulation in immature phase will have a better impact on increasing natural resistance, and it has the potential to be used as a supplement for arabica coffee plants cultivated in the lowland.

Organic vs. Integrated-Production Agriculture Farming: Which Grapevine Stress-Responsive Genes Are Affected by the Application of Resistance Inducers and Elicitors?

With the rising prominence of organic farming systems in European Union countries, motivated by agricultural policies, there is pressure for effective disease management strategies. To address this challenge, the use of plant resistance inducers (PRIs) and elicitors has emerged as a promising approach. In this study, we compared the impact of integrated production with organic agriculture farming practices, specifically applying PRIs and elicitors in the latter, on the expression levels of stress-responsive genes in two grapevine cultivars, ‘Alicante Bouschet’ and ‘Trincadeira’. Our findings revealed that the organic farming system led to upregulation of eight of the 12 studied genes in at least one cultivar, indicating a significant influence of production mode. The upregulated genes were associated with plant stress-responsive genes (PR1, PR2, PR4, and TLP9), sugar metabolism (HT5), phenylpropanoids (STS1), enzymes related to jasmonic acid synthesis and response to biotic stresses, respectively (LOX, PER42). Also, the ‘Alicante Bouschet’ cultivar consistently displayed significantly higher levels of transcript accumulation on most of the stress-related genes compared to the ‘Trincadeira’ cultivar in both production modes. Our study provides valuable insights into the effectiveness of PRIs and elicitors in increasing plant expression levels of stress-responsive genes, leading to greater resilience to pathogen attacks and emphasizing their position in organic agriculture.

Recognition of the inducible, secretory small protein OsSSP1 by the membrane receptor OsSSR1 and the co-receptor OsBAK1 confers rice resistance to the blast fungus

The plant apoplast, which serves as the frontline battleground for long-term host–pathogen interactions, harbors a wealth of disease resistance resources. However, the identification of the disease resistance proteins in the apoplast is relatively lacking. In this study, we identified the rice secretory protein OsSSP1 (Oryza sativa secretory small protein 1). OsSSP1 can be secreted into the plant apoplast, and both in vitro treatment of recombinant OsSSP1 and overexpression of OsSSP1 in rice can trigger plant immune response. The expression of OsSSP1 is suppressed significantly during Magnaporthe oryzae infection in susceptible rice Taibei 309, and OsSSP1-overexpressing lines all show strong resistance to M. oryzae. Combining the knockout and overexpression results, we found that OsSSP1 positively regulates plant immunity in response to fungal infection. Moreover, the recognition and immune response triggered by OsSSP1 depend on an uncharacterized transmembrane OsSSR1 (secretory small protein receptor 1) and the key co-receptor OsBAK1, since most of the induced immune response and resistance are lost in the absence of OsSSR1 or OsBAK1. Intriguingly, the OsSSP1 protein is relatively stable and can still induce plant resistance after 1 week of storage in the open environment, and exogenous OsSSP1 treatment for a 2-week period did not affect rice yield. Collectively, our study reveals that OsSSP1 can be secreted into the apoplast and percepted by the plasma membrane receptors OsSSR1 and OsBAK1 during fungal infection, thereby triggering the immune response to enhance plant resistance to M. oryzae. These findings providing novel resources and potential strategies for crop breeding and disease control.

Induction of Resistance to Larvae Crocidolomia pavonana F. (Lepidoptera: Crambidae) using Rhizobacteria to the Cabbage

Crocidolomia pavonana is a significant pest on cabbage that reduces the quality and quantity of cabbage. Utilizing microorganisms such as rhizobacteria is an alternative environmentally friendly control that can potentially suppress the development of this pest. The study aimed to obtain rhizobacteria isolates capable of colonizing cabbage tissue and inducing plant resistance to C. pavonana larvae. The research was conducted at the Biological Control Laboratory and Greenhouse, Faculty of Agriculture, Universitas Andalas, Padang. The study used a Completely Randomized Design (CRD) with ten treatments and five replications. The treatment consisted of rhizobacteria isolates, including Bacillus thuringiensis, Bacillus subtilis, Serratia marcescens, Stenotrophomonas maltophilia, as well as a negative control (aquadest sterile) and a positive control (Cypermethrin insecticide). The test was carried out by soaking the seeds in a suspension containing rhizobacteria with a population density of 10⁸ cells/ml. The variables observed were larval mortality, pupa and imago formation percentage, and increased salicylic acid production. The data were analyzed using variance and continued with the LSD further test at the 5% level. The results showed that all rhizobacteria isolates colonized into cabbage plant tissue could kill C. pavonana larvae and inhibit these insects' biological development. B. thuringiensis KJKB7.3 showed better results with the highest mortality value (62.67%). Soaking cabbage seeds with rhizobacteria can increase the content of salicylic acid. Based on this research, the rhizobacteria used in the research have the potential to be developed as biological agents to control C. pavonana.

Important soil microbiota's effects on plants and soils: a comprehensive 30-year systematic literature review.

Clarifying the relationship between soil microorganisms and the plant-soil system is crucial for encouraging the sustainable development of ecosystems, as soil microorganisms serve a variety of functional roles in the plant-soil system. In this work, the influence mechanisms of significant soil microbial groups on the plant-soil system and their applications in environmental remediation over the previous 30 years were reviewed using a systematic literature review (SLR) methodology. The findings demonstrated that: (1) There has been a general upward trend in the number of publications on significant microorganisms, including bacteria, fungi, and archaea. (2) Bacteria and fungi influence soil development and plant growth through organic matter decomposition, nitrogen, phosphorus, and potassium element dissolution, symbiotic relationships, plant growth hormone production, pathogen inhibition, and plant resistance induction. Archaea aid in the growth of plants by breaking down low-molecular-weight organic matter, participating in element cycles, producing plant growth hormones, and suppressing infections. (3) Microorganism principles are utilized in soil remediation, biofertilizer production, denitrification, and phosphorus removal, effectively reducing environmental pollution, preventing soil pathogen invasion, protecting vegetation health, and promoting plant growth. The three important microbial groups collectively regulate the plant-soil ecosystem and help maintain its relative stability. This work systematically summarizes the principles of important microbial groups influence plant-soil systems, providing a theoretical reference for how to control soil microbes in order to restore damaged ecosystems and enhance ecosystem resilience in the future.

Joint application of plant immunity-inducing elicitors and fungicides to control Phytophthora diseases

Phytophthora are destructive plant pathogens that pose a serious threat to crop production. Traditional control methods rely heavily on chemical fungicides, which are harmful to the environment and human health. Currently, effective green prevention and control methods for Phytophthora pathogens are lacking. Plants rely primarily on their innate immune system to resist pathogens. Plant cells perceive pathogen invasion and activate immune responses by recognizing specific pathogen-derived molecules, called elicitors, which mainly include pathogen-associated molecular patterns (PAMPs) and microbial effector proteins. PAMPs, which are conserved molecular features of microbes and recognized by plant cell surface-localized pattern-recognition receptors (PRRs), activate mild and broad-spectrum disease resistance. However, there are few reports on elicitor proteins that induce broad resistance against Phytophthora pathogens. In this study, we identified BcIEB1, a fungal-derived PAMP, which activated plant immune responses in a BAK1- and SOBIR1-dependent manner. BcIEB1 could induce plant resistance to various Phytophthora pathogens, including P. capsici, P. infestans, and P. parasitica. We further found that the combination of lower concentrations of BcIEB1 with fungicides, such as pyraclostrobin, azoxystrobin, and metalaxyl-M, could enhance the effect on Phytophthora disease control while reducing the dependence on fungicides, thereby reducing environmental pollution. This study identified a novel, less toxic strategy for controlling Phytophthora diseases.

Induced Resistance Mechanism in Plant and Its Importance in Agriculture

The search for a successful and efficient natural phenomenon of induced resistance in plants was prompted by the harmful effects that chemical pesticides and their degradation products had on the environment and human health. Ray was the first to identify plant resistance to diseases in 1901. When arabidopsis plants were injected with the pathogenic bacteria Pseudomonas fluorescens, which colonises roots, induced resistance was initially observed in these plants. There are two different kinds of induced resistance: induced biochemical defense and induced structural defense. Biochemical defense includes phytoalexins, PR-proteins, and secondary metabolites; structural defense includes cytoplasmic reactions, cell wall defense structure, and histological defense structure (development of cork layers, abscission layer, and tylose). Induced systemic resistance (ISR) and systemic acquired resistance (SAR) are the foundation of the induced resistance process. While the defense mechanism in ISR is mediated by jasmonic acid and ethylene and additionally triggered by non-pathognic rhizobacteria (Pseudomonas fluorescens), the defense mechanism in SAR is salicyclic mediated, namely alterations in gene expression. Plants can develop resistance to specific diseases by applying exogenous doses of 2, 6-dichloroisonicotonic acid and benzo-thiadiazole-7-carbothioic acid S-methyl ester (BTH). Induced resistance in plants, while still poorly understood, offers up new possibilities for plant protection and presents a viable strategy for sustainable agriculture and environmentally friendly disease control. It continues to be a problem for both basic and practical research.