Disease Suppression Research Articles

Allergen-Encapsulating Nanoparticles Reprogram Pathogenic Allergen-Specific Th2 Cells to Suppress Food Allergy.

Food allergy is a prevalent, potentially deadly disease caused by inadvertent sensitization to benign food antigens. Pathogenic Th2 cells are a major driver for disease, and allergen-specific immunotherapies (AIT) aim to increase the allergen threshold required to elicit severe allergic symptoms. However, the majority of AIT approaches require lengthy treatments and convey transient disease suppression, likely due to insufficient targeting of pathogenic Th2 responses. Here, the ability of allergen-encapsulating nanoparticles to directly suppress pathogenic Th2 responses and reactivity is investigated in a mouse model of food allergy. NPs associate with pro-tolerogenic antigen presenting cells, provoking accumulation of antigen-specific, functionally suppressive regulatory T cells in the small intestine lamina propria. Two intravenous doses of allergen encapsulated in poly(lactide-co-glycolide) nanoparticles (NPs) significantly reduces oral food challenge (OFC)-induced anaphylaxis. Importantly, NP treatment alters the fates of pathogenic allergen-specific Th2 cells, reprogramming these cells toward CD25+FoxP3+ regulatory and CD73+FR4+ anergic phenotypes. NP-mediated reductions in the frequency of effector cells in the gut and mast cell degranulation following OFC are also demonstrated. These studies reveal mechanisms by which an allergen-encapsulating NP therapy and, more broadly, allergen-specific immunotherapies, can rapidly attenuate allergic responses by targeting pathogenic Th2 cells.

Effect of chitosan-tripolyphosphate to suppress anthracnose (Colletotrichum spp.) in post-harvest chili

Anthracnose disease (Colletotrichum spp.) in chili can lead to low fruit quantity and quality from planting to the postharvest stage. The environmentally friendly management using chitosan (CS) is expected to suppress anthracnose disease and increase the shelf-life of chili. This study aimed to determine the effect of the chitosan-tripolyphosphate (CS-TPP) to suppress anthracnose on chili during postharvest storage through in-vitro and in-vivo assays. In the in-vitro assay, CS-TPP solution with a ratio of [5:2] and [3:1] was applied into a warm Potato Dextrose Agar (PDA) medium. It was grown by Colletotrichum pathogen, while on in vivo assay, CS-TPP was applied to chili fruit before being inoculated by the pathogen. A control treatment was prepared without CS-TPP application. Results revealed that the CS-TPP ratios affected the growth of Colletotrichum spp. at the in-vitro assay. The CS-TPP [5:2] ratio was more effective than CS-TPP [3:1] in reducing the growth of Colletotrichum spp. with the fungal inhibition of 62,65% and 55,56%, respectively, compared to the control treatment. Moreover, it also showed anthracnose disease suppression on chili fruit of 51%, and 29%, respectively, compared to control treatment at in-vivo assay. This study showed the potential use of CS-TPP as a coating application for anthracnose disease management on storage chili, however further study such as viability and longevity of formula need to be done.

Targeted Therapy of Multiple Sclerosis: A Case for Antigen-Specific Tregs.

Multiple sclerosis is an autoinflammatory condition that results in damage to myelinated neurons in affected patients. While disease-modifying treatments have been successful in slowing the progression of relapsing-remitting disease, most patients still progress to secondary progressive disease that is largely unresponsive to disease-modifying treatments. Similarly, there is currently no effective treatment for patients with primary progressive MS. Innate and adaptive immune cells in the CNS play a critical role in initiating an autoimmune attack and in maintaining the chronic inflammation that drives disease progression. In this review, we will focus on recent insights into the role of T cells with regulatory function in suppressing the progression of MS, and, more importantly, in promoting the remyelination and repair of MS lesions in the CNS. We will discuss the exciting potential to genetically reprogram regulatory T cells to achieve immune suppression and enhance repair locally at sites of tissue damage, while retaining a fully competent immune system outside the CNS. In the future, reprogramed regulatory T cells with defined specificity and function may provide life medicines that can persist in patients and achieve lasting disease suppression after one cycle of treatment.

Emerging Trends of Gold Nanostructures for Point-of-Care Biosensor-Based Detection of COVID-19.

In 2019, a worldwide pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged. SARS-CoV-2 is the deadly microorganism responsible for coronavirus disease 2019 (COVID-19), which has caused millions of deaths and irreversible health problems worldwide. To restrict the spread of SARS-CoV-2, accurate detection of COVID-19 is essential for the identification and control of infected cases. Although recent detection technologies such as the real-time polymerase chain reaction delivers an accurate diagnosis of SARS-CoV-2, they require a long processing duration, expensive equipment, and highly skilled personnel. Therefore, a rapid diagnosis with accurate results is indispensable to offer effective disease suppression. Nanotechnology is the backbone of current science and technology developments including nanoparticles (NPs) that can biomimic the corona and develop deep interaction with its proteins because of their identical structures on the nanoscale. Various NPs have been extensively applied in numerous medical applications, including implants, biosensors, drug delivery, and bioimaging. Among them, point-of-care biosensors mediated with gold nanoparticles (GNPSs) have received great attention due to their accurate sensing characteristics, which are widely used in the detection of amino acids, enzymes, DNA, and RNA in samples. GNPS have reconstructed the biomedical application of biosensors because of its outstanding physicochemical characteristics. This review provides an overview of emerging trends in GNP-mediated point-of-care biosensor strategies for diagnosing various mutated forms of human coronaviruses that incorporate different transducers and biomarkers. The review also specifically highlights trends in gold nanobiosensors for coronavirus detection, ranging from the initial COVID-19 outbreak to its subsequent evolution into a pandemic.

Genomic insights into Streptomyces hygroscopicus subsp. hygroscopicus SRF1: a potential biocontrol agent against fusarium wilt with plant growth-promoting abilities in tomatoes

ABSTRACT Streptomyces sp. isolate SRF1 has previously demonstrated promising results in controlling various plant fungi under in vitro conditions. However, further exploration of its genome and its efficacy in disease control and plant growth promotion under in vivo conditions is warranted. This study aimed to utilise whole genome sequencing (WGS) to classify Streptomyces sp. isolate SRF1 at the species level and predict genes associated with antagonistic ability and plant growth promotion, thereby assessing its potential as a biocontrol agent against fusarium wilt and a promoter of plant growth. WGS was employed to elucidate the taxonomic classification of isolate SRF1 and predict genes involved in disease suppression and plant growth promotion. In vitro assays were conducted to evaluate its antagonistic activity against Fusarium oxysporum f. sp. lycopersici (Fol) and its production of cellulase, amylase, indole-3-acetic acid (IAA), and siderophores. Pot experiments were carried out using SRF1 cell suspension and culture filtrate to assess its efficacy against Fol and its impact on tomato growth. Real-time PCR analysis was performed to correlate gene expression levels with observed activities. The results showed that isolate SRF1 was classified as S. hygroscopicus subsp. hygroscopicus and demonstrated antagonism against Fol. Furthermore, WGS revealed genes or gene clusters associated with disease control, including those encoding antifungal agents such as butyrolactol A, nigericin, and hygromycin A. Additionally, genes responsible for auxin biosynthesis, siderophore production, and carbohydrate-digesting enzymes such as chitinase, cellulase, and amylase were identified, suggesting potential roles in disease suppression and plant growth promotion.

Sequential regulation of Lck K63-ubiquitination and autophosphorylation by the E3 ligase UBR2 and the phosphatase DUSP22 in TCR signaling

Abstract Dual-specificity phosphatase 22 (DUSP22, also named JKAP) downregulation in peripheral blood T cells is correlated with human SLE nephritis and T-cell leukemia. DUSP22 also dephosphorylates and inactivates Lck in the turn-off stage of TCR signaling, leading to suppression of autoimmune disease. We found that DUSP22 dephosphorylated the E3 ligase UBR2, leading to SCF E3 ubiquitin complex-mediated UBR2 ubiquitination and degradation. Remarkably, UBR2 induced Lck K63-linked ubiquitination, leading to subsequent Lck Tyr394 autophosphorylation and activation upon TCR signaling. Thus, DUSP22 also can inactivate Lck indirectly by inducing UBR2 degradation. Moreover, the proinflammatory cytokine induction and inflammatory responses in DUSP22 KO mice was blocked by knocking out UBR2 in DUSP22/UBR2 double KO mice. The UBR2-Lck interaction and Lck Lys63-linked ubiquitination were indeed induced in T cells of human SLE patients. Taken together, DUSP22 dephosphorylates UBR2 and induces its degradation, leading to inactivation of Lck and suppression of inflammation. Overall, our results reveal a novel activation mechanism of Lck by K63-linked ubiquitination in TCR signaling.

Abstract 3013: Indoleamine 2,3-dioxygenase-mediated Tryptophan Catabolism Limits Experimental Abdominal Aortic Aneurysms

Background: Indoleamine 2,3-dioxygenase (IDO) promotes immunosuppression. Genetic IDO deficiency limits angiotensin II-induced abdominal aortic aneurysms (AAAs) in hyperlipidemic mice. We investigated the influence of IDO inhibition or IDO-catabolized tryptophan catabolite on elastase-induced AAAs in normolipidemic mice. Methods: AAAs were induced in male C57B/6J mice via intra-aortic porcine pancreatic elastase (PPE) infusion. Mice were treated with IDO inhibitor 1-methyl-DL-tryptophan (MT, 2 mg/ml in drinking water), tryptophan metabolite 3-hydroxyanthranilic acid (HAA, 200 mg/kg, oral gavage), or vehicle, starting 3 days prior to PPE infusion for 17 days. AAAs were assessed via ultrasonography and histopathology at sacrifice. Results: The Figure summarizes aortic diameters and histopathology in differentially treated PPE-infused mice. Rapid aortic enlargement was noted in MT-, as compared to vehicle-treated mice following PPE infusion. AAA rupture, unusual for this model, was noted in MT-treated AAA mice. No difference was noted between groups in medial elastin degradation, smooth muscle cell depletion, or macrophage accumulation. However, mural neoangiogenesis and lymphocyte accumulation were remarkably augmented in MT-treated mice. HAA Treatment attenuated aortic enlargement in conjunction with improved medial elastin and smooth muscle cell retention and reduced aortic leukocyte accumulation and neovessels. Conclusion: IDO activity and its tryptophan metabolite HAA limit experimental AAA progression in the PPE model. These results provide further support for investigating tryptophan metabolites in clinical AAA disease suppression.

Endophytic Fungi Residing within Cornus florida L. in Mid-Tennessee: Phylogenetic Diversity, Enzymatic Properties, and Potential Role in Plant Health.

Endophytic fungi that reside internally in healthy, asymptomatic plants often benefit their hosts by promoting plant growth and/or providing plant protection against abiotic and biotic stresses. However, only a small fraction of the estimated 1.5 million fungal endophytes have been identified. In this study, a total of 369 isolates of fungal endophytes in 59 distinct taxa were isolated from stem samples of Cornus florida (flowering dogwood). All isolates belonged to species of phyla Ascomycota and Basidiomycota distributed across five orders and 11 genera. Isolates belonging to the same family clustered together in a phylogenetic tree generated from a cluster analysis using MEGA 7 software. Diversity indices of the fungi revealed a rich and diverse community that included several species associated with leaf spots, blight, cankers, and/or dieback diseases. Pathogenicity tests confirmed 16 fungal endophytes as C. florida pathogens, including some well-known destructive pathogens Botryosphaera dothidea, Colletotrichum acutatum, and C. gleosporoides. Isolates of the fungal endophytes possess the capacity to produce extracellular hydrolytic enzymes (cellulase, amylase, pectinase, laccase, chitinase, and protease) that are known to function in tissue penetration, plant colonization, nutrient acquisition, and disease suppression in both plant pathogens and endophytes These results support the interchangeable pathogenic-endophytic roles for some taxa.

Flooding soil with biogas slurry suppresses root-knot nematodes and alters soil nematode communities

Root-knot nematodes (RKNs) pose a serious threat to crop production. Flooding soil with biogas slurry, combined with soil heating before crop planting, has the potential for RKN disease suppression. However, the actual effect of this method has not been verified under field conditions. Here, we present the results of a two-year field experiment in a greenhouse demonstrating the control effect on RKN disease and plant growth using this method, as well as its influence on the soil nematode community. Four treatments were set: untreated control (CK), local control method for RKN (CC), soil flooded with 70 % biogas slurry (BS70), and soil flooded with undiluted biogas slurry (BS100). In the first year, all three RKN control treatments significantly reduced the root-knot index (p < 0.05). In the next year, only BS70 and BS100 still presented significantly suppressed effects (p < 0.05), and it was more obvious under BS70 with a relative control effect of 74.6 %. In the first year, BS70 and BS100 significantly inhibited the plant height of watermelon (p < 0.05). In the next year, however, all three RKN control treatments promoted the growth of watermelon, and their stem diameter was significantly greater than that of CK. The application of biogas slurry (BS70 and BS100) significantly increased nematode richness and the Shannon index in the second year (p < 0.05). However, the structure index showed no significant difference among treatments (p > 0.05), indicating that biogas slurry application did not increase the soil food web complex. Principal component analysis showed that the application of biogas slurry changed the nematode community, especially under BS70, which presented a more lasting influence. The high-level input of biogas slurry also caused soil NH4+-N and heavy-metal and arsenic accumulation in the first year, but these soil-pollution risks disappeared in the second year.

Differentiation of clubroot disease suppression in Pak choi under different concentrations of Trichoderma harzianum and fluazinam

Differentiation of clubroot disease suppression in Pak choi under different concentrations of Trichoderma harzianum and fluazinam

Comparative Effect of Seed Coating and Biopriming of Bacillus aryabhattai Z-48 on Seedling Growth, Growth Promotion, and Suppression of Fusarium Wilt Disease of Tomato Plants.

Beneficial plant microbes can enhance the growth and quality of field crops. However, the benefits of microbes using cheap and efficient inoculation methods are still uncommon. Seed coating with biocontrol agents can reduce the amount of inocula along with having the potential for large-scale application. Hence, in this research work, the comparative potential of tomato seed coating and biopriming with Bacillus aryabhattai Z-48, harboring multiple plant-beneficial traits, to suppress Fusarium wilt disease along with its beneficial effect on seedling and plant growth promotion was analyzed. Among two bacterial strains, B. aryabhattai Z-48 was able to antagonize the mycelial growth of Fusarium oxysporum f.sp. lycopersici in vitro and its application as a seed coating superiorly benefited seedling traits like the germination percentage, vigor index, and seedling growth index along with a reduced germination time. The seed coating with B. aryabhattai Z-48 resulted in significant increases in the shoot length, root length, dry biomass, and total chlorophyll contents when compared with the bioprimed seeds with the same bacterial strain and non-inoculated control plants. The seed coating with B. aryabhattai Z-48 significantly reduced the disease index (>60%) compared with the pathogen control during pot trials. Additionally, the seed coating with B. aryabhattai Z-48 resulted in a significantly higher production of total phenolics, peroxidase, polyphenol oxidase, and phenylalanine ammonia lyase enzyme in tomato plants. The GC/MS-based non-targeted metabolic profiling indicated that the seed coating with B. aryabhattai Z-48 could cause large-scale metabolite perturbations in sugars, sugar alcohols, amino acids, and organic acids to increase the fitness of tomato plants against biotic stress. Our study indicates that a tomato seed coating with B. aryabhattai Z-48 can improve tomato growth and suppress Fusarium wilt disease effectively under conventional agricultural systems.

Iron Oxide Nanoparticles Inhibit Tumor Progression and Suppress Lung Metastases in Mouse Models of Breast Cancer.

Systemic exposure to starch-coated iron oxide nanoparticles (IONPs) can stimulate antitumor T cell responses, even when little IONP is retained within the tumor. Here, we demonstrate in mouse models of metastatic breast cancer that IONPs can alter the host immune landscape, leading to systemic immune-mediated disease suppression. We report that a single intravenous injection of IONPs can inhibit primary tumor growth, suppress metastases, and extend survival. Gene expression analysis revealed the activation of Toll-like receptor (TLR) pathways involving signaling via Toll/Interleukin-1 receptor domain-containing adaptor-inducing IFN-β (TRIF), a TLR pathway adaptor protein. Requisite participation of TRIF in suppressing tumor progression was demonstrated with histopathologic evidence of upregulated IFN-regulatory factor 3 (IRF3), a downstream protein, and confirmed in a TRIF knockout syngeneic mouse model of metastatic breast cancer. Neither starch-coated polystyrene nanoparticles lacking iron, nor iron-containing dextran-coated parenteral iron replacement agent, induced significant antitumor effects, suggesting a dependence on the type of IONP formulation. Analysis of multiple independent clinical databases supports a hypothesis that upregulation of TLR3 and IRF3 correlates with increased overall survival among breast cancer patients. Taken together, these data support a compelling rationale to re-examine IONP formulations as harboring anticancer immune (nano)adjuvant properties to generate a therapeutic benefit without requiring uptake by cancer cells.

Disentangling Shifts in the Soil Microbiome of Potatoes Infected with Rhizoctonia solani Anastomosis Group 3-PT in Search of Potential Biocontrol Agents

Rhizoctonia solani anastomosis group (AG) 3-PT is a devastating pathogenic fungus that causes several diseases in potatoes both in South Africa and globally. The removal of various fungicides from the market and strict regulations on the use of synthetic chemicals make disease management difficult. Therefore, alternative, environmentally safe control measures are being considered, such as the use of biological control agents (BCAs). BCAs are an attractive alternative for improving plant and soil health of economically important crops. To identify key microbial indicators of disease suppression against R. solani AG 3-PT, a greenhouse pot trial experiment was conducted using soil from a potato-growing region in KwaZulu-Natal, South Africa. High-throughput sequencing of fungal internal transcribed spacer and bacterial 16S ribosomal RNA was used to characterize the respective fungal and bacterial community composition in the soil with and without artificial inoculation with R. solani AG 3-PT. Results indicated that the pathogen caused dysbiosis in the potato soil microbiome, leading to a shift in fungal and bacterial community composition. Differentially abundant microbial taxa in R. solani AG 3-PT inoculated soils suggest a promising potential for disease-suppressive activity. Network analysis also confirmed the presence of key taxa involved in the microbial community shifts, which could support their role in the suppression of R. solani AG 3-PT. The identification of key microbial indicators against Rhizoctonia diseases can contribute to the development of environmentally sustainable potato production systems, which are particularly important considering the implementation of the European Green Deal.

Root rot induces a core assemblage of bacterial microbiome to prevent disease infection in Sanqi ginseng

Plants rely on rhizosphere microbes as the first line of defense against pathogen invasion and for maintaining the health of itself. Increasing evidence suggests that plants recruit beneficial microbes to the roots, strengthening their resistance to pathogens. However, the response of the rhizosphere core bacterial microbiome to root rot infection remains largely unclear. In this study, we investigated the rhizosphere and bulk soil core bacterial microbiome of healthy and root rot-diseased Sanqi ginseng in genuine production areas in China. We utilized 16S amplicon sequencing, co-occurrence network analysis, and strain culture approaches to explore whether root rot-induced plant rhizosphere alterations in the bacterial core microbiome could improve disease suppression. Root rot infection had a significant impact on the rhizosphere core bacterial microbiome of Sanqi ginseng. Root rot led to a reduction in the diversity and evenness of the core bacterial microbiome in the rhizosphere, while the variability of the core bacterial community in the rhizosphere increased. In response to fungal root rot pathogen infestation, Sanqi ginseng recruited potentially beneficial bacteria with disease-suppressive functions to the rhizosphere, such as Sphingobium, Pseudoxanthomonas, Pseudomonas, Stenotrophomonas, and Flavobacterium. Function prediction analysis demonstrated a remarkable enrichment of several functional genes involved in antibiotic biosynthesis in the rhizosphere that was infected with root rot. Strain isolation and pot addition experiments further confirmed the effectiveness of root rot rhizosphere-specific enrichment of Operational Taxonomic Units (OTUs) for controlling root rot. Furthermore, co-occurrence network analysis indicated that root rot activated the disease-suppressive functions of the rhizosphere core bacterial microbiome by enhancing complexity and connectivity at the expense of network stability. These findings expand our knowledge of plant-microbe interactions and provides new evidence supporting the “cry for help” strategy for rhizosphere responses to root rot.

Rhizoctonia solani disease suppression: addition of keratin-rich soil amendment leads to functional shifts in soil microbial communities.

Promoting soil suppressiveness against soil borne pathogens could be a promising strategy to manage crop diseases. One way to increase the suppression potential in agricultural soils is via the addition of organic amendments. This microbe-mediated phenomenon, although not fully understood, prompted our study to explore the microbial taxa and functional properties associated with Rhizoctonia solani disease suppression in sugar beet seedlings after amending soil with a keratin-rich waste stream. Soil samples were analyzed using shotgun metagenomics sequencing. Results showed that both amended soils were enriched in bacterial families found in disease suppressive soils before, indicating that the amendment of keratin-rich material can support the transformation into a suppressive soil. On a functional level, genes encoding keratinolytic enzymes were found to be abundant in the keratin-amended samples. Proteins enriched in amended soils were those potentially involved in the production of secondary metabolites/antibiotics, motility, keratin-degradation, and contractile secretion system proteins. We hypothesize these taxa contribute to the amendment-induced suppression effect due to their genomic potential to produce antibiotics, secrete effectors via the contractile secretion system, and degrade oxalate-a potential virulence factor of R. solani-while simultaneously possessing the ability to metabolize keratin.

Biological Control of Gummy Stem Blight Caused by Didymella bryoniae (Auersw.) on Watermelon by Bacillus sp. Strains

Background: The gummy stem blight caused by the fungal pathogen Didymella bryoniae (Auersw.) is a common and serious disease of watermelon plants in Vietnam. Bacillus species have been used to control plant diseases as biological control agents. The objectives of this studies were to determine the fungal inhibition of D. bryoniae and disease suppression of gummy stem blight under greenhouse by Bacillus sp. strains. Methods: The study was carried out at University of Agriculture and Forestry, Hue University during 2022-2023. Six potential Bacillus strains namely S1A1, S1F3, S13E2, S13E3, S18F11 and S20D12 isolated from stem-base of groundnut in central Vietnam were tested its fungal inhibition of D. bryoniae and disease suppression of gummy stem blight. Result: All tested strains of Bacillus sp. showed inhibition of the hyphal growth of D. bryoniae strain DB-01 in potato dextrose broth. Among the strains, Bacillus sp. S20F12 had highest inhibition of the growth of mycelia of D. bryoniae strain DB-01 with an antagonistic efficiency of 65.7% at 10 days after fungal inoculation. By 21 days after fungal inoculation, disease incidences were low in the plants treated with Bacillus sp. S20D12 and S1F3 by 46.6 and 50.0% and disease severity by 15,3% and 20.6%, respectively. As results, watermelon plants were prevented from damage of gummy stem blight caused by D. bryoniae strain BD-01 by Bacillus sp. S20D12 and S1F13. The results would contribute to the knowledge of antagonistic activities of the Bacillus to optimize the biological control against D. bryoniae.

Comparative analysis on root exudate and rhizosphere soil bacterial assembly between tomatoes and peppers infected by Ralstonia

BackgroundThe rhizosphere environment regulated by root secretory activity and rhizosphere microbial interactions plays an essential role in resisting soil-borne diseases, while the host species is an important factor that affects the composition of root exudates and rhizosphere microbiomes. However, few studies have been done on the characteristics of root exudates and bacterial communities in terms of composition, diversity, and functional potential when host plants of different species are subjected to the same disease.ResultsIn this study, we examined the rhizosphere soil bacteria and root exudates of both healthy and diseased tomatoes and peppers employing metabolomics and amplicon techniques. Our findings indicated that variations existed in both root exudates and the bacterial community among different host species and health states. The diversities of both rhizosphere metabolites and bacterial communities were significantly reduced in different diseased plants. Although pepper and tomato resisted the invasion of Ralstonia by recruiting different potentially beneficial bacteria, their rhizosphere bacterial communities had the same functional potential. In comparison to diseased rhizosphere soil, healthy rhizosphere soil had many more functional pathways associated with disease suppression and plant growth.ConclusionsThis study highlighted the crucial role of host plants in shaping the rhizosphere environment and revealed the variation characteristics of root exudates and rhizosphere bacteria of different host plants induced by the same disease.Graphical

Biological control potential of worrisome wheat blast disease by the seed endophytic bacilli.

Crop production often faces challenges from plant diseases, and biological control emerges as an effective, environmentally friendly, cost-effective, and sustainable alternative to chemical control. Wheat blast disease caused by fungal pathogen Magnaporthe oryzae Triticum (MoT), is a potential catastrophic threat to global food security. This study aimed to identify potential bacterial isolates from rice and wheat seeds with inhibitory effects against MoT. In dual culture and seedling assays, three bacterial isolates (BTS-3, BTS-4, and BTLK6A) demonstrated effective suppression of MoT growth and reduced wheat blast severity when artificially inoculated at the seedling stage. Genome phylogeny identified these isolates as Bacillus subtilis (BTS-3) and B. velezensis (BTS-4 and BTLK6A). Whole-genome analysis revealed the presence of genes responsible for controlling MoT through antimicrobial defense, antioxidant defense, cell wall degradation, and induced systemic resistance (ISR). Taken together, our results suggest that the suppression of wheat blast disease by seed endophytic B. subtilis (BTS-3) and B. velezensis (BTS-4 and BTLK6A) is liked with antibiosis and induced systemic resistance to wheat plants. A further field validation is needed before recommending these endophytic bacteria for biological control of wheat blast.

Suppression of Sugarcane Red Rot Disease through Its Rhizospheric Mycoflora

Red rot disease of sugarcane is so devastating in nature that it has been referred to as “cancer of sugarcane”. The sugar industry in India suffered losses more than 500 million US dollars every year due to red rot. So, there is a need to look over the management and control of the disease. Biological control method is an alternative method of chemical pesticides which are an innovative, cost effective and eco-friendly approach. Soil samples were collected from sugarcane rhizosphere of four different varieties viz., CoPk 05191 and CoLk 94184 (resistant to red rot) and CoJ 64 and Co 1148 (susceptible to red rot) planted at ICAR-Indian Institute of Sugarcane Research, Lucknow experimental farm. The samples were subjected for the isolation of rhizospheric mycoflora on Potato Dextrose Agar media and antagonistic activities of the isolates were tested against red rot pathogens (Cf 07, Cf 08 and Cf 09). Isolates showing more than 50 % inhibition with all the three pathotypes (Cf 07, Cf 08 and Cf 09) were selected for further study. Among the twelve selected isolates used for field experiment for the management of red rot, isolate T16 was found to be highly effective. The suppression of red rot offered by rhizospheric isolates is probably due to induced systemic resistance in sugarcane plants or by the enzymatic action of metabolites produced by the rhizospheric mycoflora. The different levels of red rot infected seed cane viz., 5%, 10%, 15%, 20%, 25%, 30%, 35% and 40% were treated with MHAT and planted along with healthy seed canes, infected seed canes, as a control to work out the losses caused by different level of red rot seed infection. The result revealed that a yield loss was recorded with the infected seed. The losses were directly proportionate with the level of red rot infected seed.

Morphological and Biochemical Characterization of Phyllosphere Bacteria

Phyllosphere bacteria, residing on the surfaces of plant leaves, play crucial roles in plant health and environmental processes. This study aimed to investigate the morphological and biochemical traits of the isolated phyllosphere bacteria from cereal plant species. Isolates were collected from the leaves of different cereal plants and subjected to morphological and biochemical assays were performed to characterize their metabolic capabilities. Results revealed a diverse array of morphotypes, including cocci and bacilli, indicating the presence of varied bacterial species in the phyllosphere. Furthermore, a set of biochemical analyses highlighted metabolic versatility among isolates, with varying abilities to utilize different carbon sources and produce enzymes. These findings underscore the heterogeneity and metabolic diversity of phyllosphere bacteria, suggesting their potential roles in nutrient cycling, plant growth promotion and disease suppression. Further exploration of these characteristics could elucidate the mechanisms underlying plant-microbe interactions in the phyllosphere and inform strategies for sustainable agriculture and environmental management.