RESUMEN
Wheat leaf blight caused by Bipolaris sorokiniana is a widespread fungal disease that poses a serious risk to wheat. Biological control without causing environmental pollution is one of the safest and most effective method to control plant diseases. The antagonistic bacterial strain HeN-7 (identified as Bacillus velezensis) was isolated from tobacco leaves cultivated in Henan province, China. The results of different concentrations of cell-free supernatant (CFS) from HeN-7 culture against B. sorokiniana mycelia showed that 20% HeN-7 CFS (v/v) reached the maximum inhibition rate of 96%. In the potted plants control assay, B. velezensis HeN-7 CFS exhibited remarkable biocontrol activity on the wheat infected with B. sorokiniana, the best pot control efficacy was 65% at 20% CFS. The research on the mechanism of action demonstrated that HeN-7 CFS induced the membrane lipid peroxidation in B. sorokiniana, leading to the disruption of cell membrane integrity and resulting in the leakage of cell contents; in addition, the intracellular mitochondrial membrane potential in mycelium dissipated and reactive oxygen species accumulated, thereby inhibiting the growth of B. sorokiniana. These results indicate that B. velezensis HeN-7 is a promising candidate as a biological control agent against Bipolaris sorokiniana infection.
Asunto(s)
Bacillus , Bipolaris , Nicotiana , Enfermedades de las Plantas , Hojas de la Planta , Bacillus/aislamiento & purificación , Bacillus/metabolismo , Bacillus/fisiología , Hojas de la Planta/microbiología , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/prevención & control , Nicotiana/microbiología , Triticum/microbiología , Antifúngicos/farmacología , Antifúngicos/metabolismo , China , Especies Reactivas de Oxígeno/metabolismo , Micelio/crecimiento & desarrollo , AntibiosisRESUMEN
Sugarcane (Saccharum spp.)is an economically useful crop grown globally for sugar, ethanol and biofuel production. The crop is vulnerable to fungus Colletotrichum falcatum known to cause red rot disease. The pathogen hydrolyses stalk parenchyma cells where sucrose is accumulated resulting in upto 75% losses in sugar recovery. In this study, transgenic sugarcane having resistance against red rot was developed by introducing Trichoderma spp. endochitinase following Agrobacterium mediated transformation. The transgene introduction and expression in genetically modified plants were verified through qRT-PCR revealing upto 6-fold enhancement in endochitinase expression than non-transgenic plants. Hyperspectral Imaging of transgenic plants displayed altered leaf reflectance spectra and vegetative indices that were positively correlated with ransgene expression. The bioassay with virulent pathotypes of C. falcatumCF08 and CF13 known for epiphytotic occurrence resulted in identification of resistant plant Chit 3-13.The plants with higher reflectance also displayed improved disease resistance, implying their early classification into resistant/susceptible. The losses in sucrose content were minimized (up to 4-fold) in inoculated resistant plant Chit 3-13 as compared to susceptible non-transgenic plant, and a fewer pathogen hyphae were detected in vascular cells of the former through optical microscopy. The electron micrographs confirmed sucrose-filled stalk parenchyma cells in Chit 3-13; in contrast, cells of non-transgenic inoculated plant were depleted of sucrose. The active sites involved in cleaving 1-4 ß-glycoside bonds of N-acetyl-d-glucosaminein the pathogen hyphal walls were detected through endochitinase protein structural modelling. The transgenic sugarcane is an important source for in trogressingred rot resistance in plant breeding programs.
Asunto(s)
Quitinasas , Colletotrichum , Resistencia a la Enfermedad , Enfermedades de las Plantas , Plantas Modificadas Genéticamente , Saccharum , Trichoderma , Saccharum/microbiología , Saccharum/genética , Resistencia a la Enfermedad/genética , Plantas Modificadas Genéticamente/microbiología , Plantas Modificadas Genéticamente/genética , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/genética , Colletotrichum/patogenicidad , Trichoderma/genética , Quitinasas/genética , Quitinasas/metabolismo , Hojas de la Planta/microbiología , Hojas de la Planta/genéticaRESUMEN
BACKGROUND: Pseudomonas eucalypticola, a new species of the P. fluorescens group that generates most Pseudomonas-based biocontrol agents, has not been found in any plants other than Eucalyptus dunnii leaves. Except for antagonism to the growth of a few fungi, its features in plant growth promotion and disease control have not been evaluated. Here, we identified a similar species of P. eucalypticola, 1021Bp, from endophyte cultures of healthy leaves of English boxwood (Buxus sempervirens 'Suffruticosa') and investigated its antifungal activity, plant growth promotion traits, and potential for boxwood blight control. RESULTS: Colorimetric or plate assays showed the properties of 1021Bp in nitrogen fixation, phosphate solubilization, and production of indole-3-acetic acid (IAA) and siderophores, as well as the growth suppression of all five plant fungal pathogens, including causal agents of widespread plant diseases, gray mold, and anthracnose. Boxwood plant leaves received 87.4% and 65.8% protection from infection when sprayed with cell-free cultural supernatant (CFS) but not the resuspended bacterial cells at 108-9/mL of 1021Bp at one and seven days before inoculation (dbi) with boxwood blight pathogen, Calonectria pseudonaviculata, at 5 × 104 spores/mL. They also received similarly high protection with the 1021Bp cell culture without separation of cells and CFS at 14 dbi (67.5%), suggesting a key role of 1021Bp metabolites in disease control. CONCLUSIONS: Given the features of plant growth and health and its similarity to P. eucalypticola with the P. fluorescens lineage, 1021Bp has great potential to be developed as a safe and environmentally friendly biofungicide and biofertilizer. However, its metabolites are the major contributors to 1021Bp activity for plant growth and health. Application with the bacterial cells alone, especially with nonionic surfactants, may result in poor performance unless survival conditions are present.
Asunto(s)
Enfermedades de las Plantas , Hojas de la Planta , Pseudomonas , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/prevención & control , Pseudomonas/genética , Pseudomonas/crecimiento & desarrollo , Pseudomonas/metabolismo , Hojas de la Planta/microbiología , Antibiosis , Ácidos Indolacéticos/metabolismo , Hongos/crecimiento & desarrollo , Hongos/genética , Hongos/clasificación , Hongos/efectos de los fármacos , Sideróforos/metabolismo , Endófitos/metabolismo , Endófitos/genética , Desarrollo de la Planta , Agentes de Control Biológico , Antifúngicos/farmacología , Antifúngicos/metabolismoRESUMEN
Roasted-rice leachate fermentation, a distinctive local tobacco fermentation method in Sichuan, imparts a mellow flavor and glossy texture to tobacco leaves, along with a roasted rice aroma. In order to find out the impact of roasted-rice leachate on cigar tobacco leaves, the physicochemical properties, volatile flavor profile, and microbial community were investigated. The content of protein significantly decreased after fermentation. The volatile flavor compounds increased following roasted-rice leachate fermentation, including aldehydes, alcohols, acids, and esters. High-throughput sequencing identified Staphylococcus, Pseudomonas, Pantoea, Oceanobacillus, Delftia, Corynebacterium, Sphingomonas, Aspergillus, Weissella, and Debaryomyces as the primary genera. Network and correlation analysis showed Debaryomyces played a crucial role in roasted-rice leachate fermentation, due to its numerous connections with other microbes and positive relationships with linoelaidic acid, aromandendrene, and benzaldehyde. This study is useful for gaining insight into the relationship between flavor compounds and microorganisms and provides references regarding the effect of extra nutrients on traditional fermentation products. KEY POINTS: ⢠Volatile flavor compounds increased following roasted-rice leachate fermentation ⢠Staphylococcus was the primary genera in fermented cigar ⢠Debaryomyces may improve the quality of tobacco leaves.
Asunto(s)
Bacterias , Fermentación , Aromatizantes , Oryza , Compuestos Orgánicos Volátiles , Compuestos Orgánicos Volátiles/metabolismo , Compuestos Orgánicos Volátiles/análisis , Aromatizantes/metabolismo , Oryza/microbiología , Bacterias/metabolismo , Bacterias/clasificación , Bacterias/genética , Bacterias/aislamiento & purificación , Hojas de la Planta/microbiología , Productos de Tabaco , Gusto , Nicotiana/microbiología , Microbiota , Odorantes/análisisRESUMEN
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.
Asunto(s)
Redes Neurales de la Computación , Enfermedades de las Plantas , Solanum lycopersicum , Solanum lycopersicum/microbiología , Solanum lycopersicum/crecimiento & desarrollo , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/estadística & datos numéricos , Agricultura/métodos , Productos Agrícolas/microbiología , Productos Agrícolas/crecimiento & desarrollo , Hojas de la Planta/microbiologíaRESUMEN
Salinity stress negatively affects the growth and yield of crops worldwide. Onion (Allium cepa L.) is moderately sensitive to salinity. Beneficial microorganisms can potentially confer salinity tolerance. This study investigated the effects of endomycorrhizal fungi (M), Pseudomonas putida (Ps) and their combination (MPs) on onion growth under control (0 ppm), moderate (2000 ppm) and high (4000 ppm) NaCl salinity levels. A pot experiment was conducted with sandy loam soil and onion cultivar Giza 20. Results showed that salinity reduced growth attributes, leaf pigments, biomass and bulb yield while increasing oxidative stress markers. However, individual or combined inoculations significantly increased plant height, bulb diameter and biomass production compared to uninoculated plants under saline conditions. MPs treatment provided the highest stimulation, followed by Pseudomonas and mycorrhizae alone. Overall, dual microbial inoculation showed synergistic interaction, conferring maximum benefits for onion growth, bulbing through integrated physiological and biochemical processes under salinity. Bulb yield showed 3.5, 36 and 83% increase over control at 0, 2000 and 4000 ppm salinity, respectively. In conclusion, combined application of mycorrhizal-Pseudomonas inoculations (MPs) effectively mitigate salinity stress. This approach serves as a promising biotechnology for ensuring sustainable onion productivity under saline conditions.
Asunto(s)
Cebollas , Pseudomonas putida , Salinidad , Pseudomonas putida/fisiología , Pseudomonas putida/crecimiento & desarrollo , Pseudomonas putida/efectos de los fármacos , Cebollas/microbiología , Micorrizas/fisiología , Biomasa , Estrés Salino , Raíces de Plantas/microbiología , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/efectos de los fármacos , Tolerancia a la Sal , Hojas de la Planta/microbiología , Hojas de la Planta/metabolismo , Estrés Oxidativo/efectos de los fármacosRESUMEN
Soybean is an economically important crop for animal and human nutrition. Currently, there is a lack of information on the effects of Trichoderma harzianum and Purpureocillum lilacinum on INTACTA RR PRO transgenic soybean plants. The present study evaluated the application of T. harzianum and P. lilacinum under field conditions. The results revealed a significant increase in soybean yield at 423 kg ha-1 in response to the application of P. lilacinum compared with the control treatment. In addition, the application of P. lilacinum promoted a significant increase in phosphorus levels in the plant leaves, and there were significant correlations between the increase in taxon abundance for the genus Erwinia and productivity and the average phosphorus and nitrogen content for the plant leaves, for the taxon Bacillus and nitrogen content and productivity, and for the taxon Sphingomonas and nitrogen content. The Bradyrhizobium taxon was identified in the P. lilacinum treatment as a taxon linking two different networks of taxa and is an important taxon in the microbiota. The results show that the application of the fungus P. lilacinum can increase the productivity of soybean INTACTA RR PRO and that this increase in productivity may be a function of the modulation of the microbiota composition of the plant leaves by the P. lilacinum effect.
Asunto(s)
Glycine max , Hypocreales , Microbiota , Nitrógeno , Fósforo , Glycine max/microbiología , Glycine max/crecimiento & desarrollo , Glycine max/metabolismo , Hypocreales/genética , Hypocreales/crecimiento & desarrollo , Hypocreales/metabolismo , Nitrógeno/metabolismo , Fósforo/metabolismo , Hojas de la Planta/microbiología , Plantas Modificadas GenéticamenteRESUMEN
This study investigates the colonization of endophytic fungi in nettle leaf tissues and evaluates their antibacterial and antioxidant activities. Using an inverted optical microscope, extensive fungal colonization was observed in all leaf parts, with hyphae prevalent in epidermal cells, parenchyma cells, and vascular tissues. 144 endophytic fungal isolates were isolated from 800 leaf fragments, indicating an 18% retention rate. ANOVA analysis revealed significant differences (p < 0. 001) in colonization frequencies among 20 subjects, with subject 3 showing the highest frequency (40%) and subject 11 the lowest (2. 5%). Ethyl acetate extracts of the three most abundant endophytic fungi demonstrated notable antibacterial activity against both Gram-positive and Gram-negative bacteria, including methicillin-resistant Staphylococcus aureus (MRSA). Inhibition zones ranged from 9. 5 to 15. 16 mm, with minimum inhibitory concentrations (MICs) between 0. 19 to 25 mg/mL. Alternaria sp. exhibited the highest antimicrobial activity against MRSA. Antioxidant activity was assessed using the DPPH radical scavenging test and FRAP method. All extracts showed substantial free radical scavenging properties, with IC50 values close to those of standards like BHT. Alternaria sp. had the highest antioxidant activity, followed by Epicocum sp. and Ulocladium sp. The FRAP method confirmed high reducing potential, with Alternaria sp. again exhibiting the highest activity. These findings highlight the potential of endophytic fungi in nettle leaves as sources of antimicrobial and antioxidant agents, with significant implications for pharmaceutical and biotechnological applications.
Asunto(s)
Antiinfecciosos , Antioxidantes , Endófitos , Hongos , Pruebas de Sensibilidad Microbiana , Hojas de la Planta , Antioxidantes/farmacología , Antioxidantes/química , Hongos/efectos de los fármacos , Endófitos/química , Hojas de la Planta/microbiología , Hojas de la Planta/química , Antiinfecciosos/farmacología , Antiinfecciosos/química , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Antibacterianos/farmacología , Antibacterianos/químicaRESUMEN
Globally, there is a growing concern about tree mortality due to harsh climates and changes in pest and disease patterns. However, experimental studies on the interactions between biotic and abiotic stresses in plants are relatively scarce. In this study, we investigated the interaction between Fusarium solani and water-stressed Dalbergia sissoo saplings. We postulated that under drought conditions, sissoo plants would become more susceptible to dieback infestation. Five fungi, including Fusarium oxysporum, Curvularia lunata, Cladophialophora carrionii, Alternaria alternaria, and Fusarium solani, were isolated from an old shisham tree showing advanced symptoms of dieback infestation. These fungi were identified based on their ITS sequence homology and spore characteristics. Dieback development was more pronounced in plants experiencing water stress, regardless of their predisposition or whether it occurred simultaneously. Lesions were more noticeable and longer in predisposed saplings (3.8cm), followed by simultaneous (2.4cm) and much smaller lesions in seedlings that were inoculated and well-watered (0.24cm). Progressive browning of the upper leaves, which lowers sapling height in predisposed, simultaneous, and well-watered inoculated saplings to 8.09 inches, 5.93 inches, and 17.42 inches, are typical dieback symptoms. Water stress causes the loss of chlorophyll a, b, and carotenoids, which reduces stomatal conductance, transpiration rate, and photosynthetic activity, leading to poor development and mortality. Similarly, predisposed, simultaneous, and well-watered inoculated seedlings expressed increased activity of CAT (22.57, 18.148, and 9.714 U/mg) and POD (3.0, 4.848, 1.246 U/mg), to reduce the damage caused by elevated levels of H2O2 expression. It is concluded that water stress is the main cause of dieback in shisham saplings that subsequently disposed of infected seedlings to secondary agents such as fungi and insects in the advanced stages of the dieback with prolonged drought stress. The lack of dieback in native populations is attributed to the absence of several ecological stresses, including water stress, extended droughts, waterlogging, and salinity. This study emphasizes the need for additional research into the effects of abiotic factors linked with fungal diseases on the long-term production and management of D. sissoo in Pakistan.
Asunto(s)
Fusarium , Enfermedades de las Plantas , Fusarium/patogenicidad , Fusarium/fisiología , Enfermedades de las Plantas/microbiología , Hojas de la Planta/microbiología , Deshidratación , Clorofila/metabolismo , Plantones/microbiología , Agua , Alternaria/fisiología , Alternaria/patogenicidadRESUMEN
BACKGROUND: Plants have evolved various defense mechanisms against insect herbivores, including the formation of physical barriers, the synthesis of toxic metabolites, and the activation of phytohormone responses. Although plant-associated microbiota influence plant growth and health, whether they play a role in plant defense against insect pests in natural ecosystems is unknown. RESULTS: Here, we show that leaves of beetle-damaged weeping willow (Salix babylonica) trees are more resistant to the leaf beetle Plagiodera versicolora (Coleoptera) than those of undamaged leaves. Bacterial community transplantation experiments demonstrated that plant-associated microbiota from the beetle-damaged willow contribute to the resistance of the beetle-damaged willow to P. versicolora. Analysis of the composition and abundance of the microbiome revealed that Pseudomonas spp. is significantly enriched in the phyllosphere, roots, and rhizosphere soil of beetle-damaged willows relative to undamaged willows. From a total of 49 Pseudomonas strains isolated from willows and rhizosphere soil, we identified seven novel Pseudomonas strains that are toxic to P. versicolora. Moreover, re-inoculation of a synthetic microbial community (SynCom) with these Pseudomonas strains enhances willow resistance to P. versicolora. CONCLUSIONS: Collectively, our data reveal that willows can exploit specific entomopathogenic bacteria to enhance defense against P. versicolora, suggesting that there is a complex interplay among plants, insects, and plant-associated microbiota in natural ecosystems.
Asunto(s)
Escarabajos , Hojas de la Planta , Pseudomonas , Salix , Animales , Salix/microbiología , Escarabajos/microbiología , Hojas de la Planta/microbiología , Microbiota , Rizosfera , Microbiología del Suelo , Herbivoria , Raíces de Plantas/microbiología , Enfermedades de las Plantas/microbiologíaRESUMEN
Two yeast strains, NYNU 236122 and NYNU 236180, were isolated from plant leaves collected in Tianchi Mountain, Henan Province, central China. Molecular phylogenetic analyses revealed the closest relatives of the strains are three described Kondoa species, Kondoa chamaenerii, Kondoa miscanthi, and Kondoa subrosea. Genetically, the isolated strains differed from the type strains of their three related species by 2-11(0.2-1.8%) base substitutions in the D1/D2 domain, 16-40 (2.6-5.6%) base mismatches in the internal transcribed spacer region, and more than 10.1% base substitutions in the partial RPB2 gene. Furthermore, the two strains differ physiologically from their closest related species, K. chamaenerii, in their ability to assimilate dl-lactate, nitrite, and l-lysine and their inability to assimilate nitrate. Additionally, they differ from K. miscanthi and K. subrosea in their ability to assimilate inulin, d-gluconate, and l-lysine. The species name of Kondoa tianchiensis f.a., sp. nov. is proposed with holotype CICC 33616T (Mycobank MB 853544).
Asunto(s)
ADN de Hongos , Filogenia , Hojas de la Planta , Análisis de Secuencia de ADN , Hojas de la Planta/microbiología , China , ADN de Hongos/genética , Técnicas de Tipificación Micológica , Saccharomycetales/genética , Saccharomycetales/clasificación , Saccharomycetales/aislamiento & purificación , ADN Espaciador Ribosómico/genéticaRESUMEN
Recent advancements in modeling suggest that microbial inactivation in leafy greens follows a nonlinear pattern, rather than the simple first-order kinetics. In this study, we evaluated 17 inactivation models commonly used to describe microbial decline and established the conditions that govern microbial survival on leafy greens. Through a systematic review of 65 articles, we extracted 530 datasets to model the fate of Shiga toxin-producing Escherichia coli O157:H7 on leafy greens. Various factor analysis methods were employed to evaluate the impact of identified conditions on survival metrics. A two-parameter model (jm2) provided the best fit to most of both natural and antimicrobial-induced persistence datasets, whereas the one-parameter exponential model provided the best fit to less than 20% of the datasets. The jm2 model (adjusted R2 = .89) also outperformed the exponential model (adjusted R2 = .58) in fitting the pooled microbial survival data. In the context of survival metrics, the model averaging approach generated higher values than the exponential model for >4 log reduction times (LRTs), suggesting that the exponential model may be overpredicting inactivation at later time points. The random forest technique revealed that temperature and inoculum size were common factors determining inactivation in both natural and antimicrobial-induced die-offs.. The findings show the limitations of relying on the first-order survival metric of 1 LRT and considering nonlinear inactivation in produce safety decision-making.
Asunto(s)
Escherichia coli O157 , Escherichia coli O157/efectos de los fármacos , Microbiología de Alimentos , Verduras/microbiología , Viabilidad Microbiana , Hojas de la Planta/microbiología , Hojas de la Planta/químicaRESUMEN
Huanglongbing (HLB), associated with the psyllid-vectored phloem-limited bacterium, Candidatus Liberibacter asiaticus (CLas), is a disease threat to all citrus production worldwide. Currently, there are no sustainable curative or prophylactic treatments available. In this study, we utilized mass spectrometry (MS)-based metabolomics in combination with 3D molecular mapping to visualize complex chemistries within plant tissues to explore how these chemistries change in vivo in HLB-infected trees. We demonstrate how spatial information from molecular maps of branches and single leaves yields insight into the biology not accessible otherwise. In particular, we found evidence that flavonoid biosynthesis is disrupted in HLB-infected trees, and an increase in the polyamine, feruloylputrescine, is highly correlated with an increase in disease severity. Based on mechanistic details revealed by these molecular maps, followed by metabolic modeling, we formulated and tested the hypothesis that CLas infection either directly or indirectly converts the precursor compound, ferulic acid, to feruloylputrescine to suppress the antimicrobial effects of ferulic acid and biosynthetically downstream flavonoids. Using in vitro bioassays, we demonstrated that ferulic acid and bioflavonoids are indeed highly bactericidal to CLas, with the activity on par with a reference antibiotic, oxytetracycline, recently approved for HLB management. We propose these compounds should be evaluated as therapeutics alternatives to the antibiotics for HLB treatment. Overall, the utilized 3D metabolic mapping approach provides a promising methodological framework to identify pathogen-specific inhibitory compounds in planta for potential prophylactic or therapeutic applications.
Asunto(s)
Antibacterianos , Citrus , Enfermedades de las Plantas , Citrus/microbiología , Citrus/química , Enfermedades de las Plantas/microbiología , Antibacterianos/farmacología , Antibacterianos/química , Metabolómica/métodos , Liberibacter/metabolismo , Rhizobiaceae , Hojas de la Planta/microbiología , Hojas de la Planta/metabolismo , Hojas de la Planta/química , Flavonoides/farmacología , Flavonoides/química , Flavonoides/metabolismoRESUMEN
Fusarium graminearum causes Fusarium head blight (FHB) disease in wheat worldwide. Although F. graminearum is reported to secrete several effectors, their role in virulence and pathogenicity is unknown. The study aimed at identifying candidate genes with a role in pathogenicity and virulence using two different host systems, Arabidopsis thaliana and wheat, challenged with F. graminearum TN01. Detached leaf assay and histological studies revealed the virulent nature of TN01. A genome-wide in silico search revealed several candidate genes, of which 23 genes were selected based on reproducibility. Gene expression studies by reverse transcriptase-polymerase chain reaction (RT-PCR) in leaf tissues of Arabidopsis and the two wheat genotypes, the susceptible (Sonalika) and the resistant (Nobeoka Bozu/Nobeoka), compared with mock-treated controls in a time-course study using fungal- and plant-specific genes as internal controls revealed that these genes were differentially regulated. Further, expression of these candidates in F. graminearum-inoculated Sonalika and Nobeoka spikes compared with mock-treated controls revealed their role in pathogenicity and virulence. Gene ontology studies revealed that some of these secretory proteins possessed a role in apoptosis and ceratoplatanin and KP4 killer toxin syntheses. A three-dimensional protein configuration was performed by homology modeling using trRosetta. Further, real-time quantitative PCR (RT-qPCR) studies in F. graminearum-inoculated Arabidopsis and wheat at early time points of inoculation revealed an increased expression of the majority of these genes in Sonalika, suggesting their possible role in pathogenicity, whereas low mRNA abundance was observed for 11 of these genes in the resistant genotype, Nobeoka, compared with Sonalika, indicating their role in virulence of F. graminearum.
Asunto(s)
Arabidopsis , Fusarium , Enfermedades de las Plantas , Triticum , Fusarium/genética , Fusarium/patogenicidad , Enfermedades de las Plantas/microbiología , Arabidopsis/microbiología , Virulencia , Triticum/microbiología , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Genoma Fúngico , Regulación Fúngica de la Expresión Génica , Hojas de la Planta/microbiología , Perfilación de la Expresión GénicaRESUMEN
Biofertilizers are environmentally friendly compounds that can enhance plant growth and substitute for chemically synthesized products. In this research, a new strain of the bacterium Bacillus velezensis, designated JZ, was isolated from the roots of strawberry plants and exhibited potent antagonistic properties against Bacillus altitudinis m-1, a pathogen responsible for leaf spot disease in strawberry. The fermentation broth of JZ exerted an inhibition rate of 47.43% against this pathogen. Using an optimized acid precipitation method, crude extracts of lipopeptides from the JZ fermentation broth were obtained. The crude extract of B. velezensis JZ fermentation broth did not significantly disrupt the cell permeability of B. altitudinis m-1, whereas it notably reduced the Ca2+-ATPase activity on the cell membrane and markedly elevated the intracellular reactive oxygen species (ROS) concentration. To identify the active compounds within the crude extract, QTOF-MS/MS was employed, revealing four antimicrobial compounds: fengycin, iturin, surfactin, and a polyene antibiotic known as bacillaene. The strain JZ also produced various plant-growth-promoting substances, such as protease, IAA, and siderophore, which assists plants to survive under pathogen infection. These findings suggest that the JZ strain holds significant potential as a biological control agent against B. altitudinis, providing a promising avenue for the management of plant bacterial disease.
Asunto(s)
Bacillus , Fragaria , Enfermedades de las Plantas , Bacillus/metabolismo , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/prevención & control , Fragaria/microbiología , Hojas de la Planta/microbiología , Especies Reactivas de Oxígeno/metabolismo , Lipopéptidos/farmacología , Lipopéptidos/metabolismo , Agentes de Control Biológico/farmacología , AntibiosisRESUMEN
A pathogen arriving on a host typically encounters a diverse community of microbes that can shape priority effects, other within-host interactions and infection outcomes. In plants, environmental nutrients can drive trade-offs between host growth and defence and can mediate interactions between co-infecting pathogens. Nutrients may thus alter the outcome of pathogen priority effects for the host, but this possibility has received little experimental investigation. To disentangle the relationship between nutrient availability and co-infection dynamics, we factorially manipulated the nutrient availability and order of arrival of two foliar fungal pathogens (Rhizoctonia solani and Colletotrichum cereale) on the grass tall fescue (Lolium arundinaceum) and tracked disease outcomes. Nutrient addition did not influence infection rates, infection severity or plant biomass. Colletotrichum cereale facilitated R. solani, increasing its infection rate regardless of their order of inoculation. Additionally, simultaneous and C. cereale-first inoculations decreased plant growth and-in plants that did not receive nutrient addition-increased leaf nitrogen concentrations compared to uninoculated plants. These effects were partially, but not completely, explained by the duration and severity of pathogen infections. This study highlights the importance of understanding the intricate associations between the order of pathogen arrival, host nutrient availability and host defence to better predict infection outcomes.
Asunto(s)
Colletotrichum , Lolium , Nutrientes , Enfermedades de las Plantas , Enfermedades de las Plantas/microbiología , Colletotrichum/fisiología , Nutrientes/metabolismo , Lolium/microbiología , Rhizoctonia/fisiología , Coinfección/microbiología , Interacciones Huésped-Patógeno , Hojas de la Planta/microbiología , Nitrógeno/metabolismoRESUMEN
This study is the first to investigate the presence and movement of the novel Liberibacter species 'Candidatus Liberibacter brunswickensis' (CLbr) in eggplant, Solanum melongena. The psyllid, Acizzia solanicola can transmit CLbr to eggplant and CLbr can be acquired by CLbr-negative A. solanicola individuals from CLbr-positive eggplants. In planta, CLbr can replicate, move and persist. Investigation into the early development of eggplants showed that CLbr titres had increased at the inoculation site at 14 days post inoculation access period (DPIAP). CLbr had become systemic in the majority of plants tested by 28 DPIAP. The highest bacterial titres were recorded at 35 DPIAP in all samples of the inoculated leaf, the roots, stems and the midrib and petiole samples of the newest leaf (the top leaf). This finding strongly suggests that CLbr movement in planta follows the source to sink relationship as previously described for 'Ca. Liberibacter asiaticus' (CLas) and 'Ca. Liberibacter solanacearum' (CLso). No symptoms consistent with Liberibacter-associated diseases were noted for plants colonised by CLbr during this study, consistent with the hypothesis that CLbr does not cause disease of eggplant during the early stages of host colonisation. In addition, no significant differences in biomass were found between eggplant colonised with CLbr, compared to those that were exposed to CLbr-negative A. solanicola, and to control plants.
Asunto(s)
Enfermedades de las Plantas , Solanum melongena , Solanum melongena/microbiología , Enfermedades de las Plantas/microbiología , Hojas de la Planta/microbiología , Rhizobiaceae/fisiología , Liberibacter , Hemípteros/microbiología , Hemípteros/crecimiento & desarrollo , Animales , Raíces de Plantas/microbiologíaRESUMEN
This study demonstrates that root-associated Kosakonia oryziphila NP19, isolated from rice roots, is a promising plant growth-promoting bioagent and biopesticide for combating rice blast caused by Pyricularia oryzae. In vitro experiments were conducted on fresh leaves of Khao Dawk Mali 105 (KDML105) jasmine rice seedlings. The results showed that NP19 effectively inhibited the germination of P. oryzae fungal conidia. Fungal infection was suppressed across three different treatment conditions: rice colonized with NP19 and inoculated by fungal conidia, a mix of NP19 and fungal conidia concurrently inoculated on the leaves, and fungal conidia inoculation first followed by NP19 inoculation after 30 h. Additionally, NP19 reduced fungal mycelial growth by 9.9-53.4%. In pot experiments, NP19 enhanced the activities of peroxidase (POD) and superoxide dismutase (SOD) by 6.1-63.0% and 3.0-67.7%, respectively, indicating a boost in the plant's defense mechanisms. Compared to the uncolonized control, the NP19-colonized rice had 0.3-24.7% more pigment contents, 4.1% more filled grains per panicle, 26.3% greater filled grain yield, 34.4% higher harvest index, and 10.1% more content of the aroma compound 2-acetyl-1-pyrroline (2AP); for rice colonized with NP19 and infected with P. oryzae, these increases were 0.2-49.2%, 4.6%, 9.1%, 54.4%, and 7.5%, respectively. In field experiments, blast-infected rice that was colonized and/or inoculated with NP19 treatments had 15.1-27.2% more filled grains per panicle, 103.6-119.8% greater filled grain yield, and 18.0-35.8% higher 2AP content. A higher SOD activity (6.9-29.5%) was also observed in the above-mentioned rice than in the blast-infected rice that was not colonized and inoculated with NP19. Following blast infection, NP19 applied to leaves decreased blast lesion progression. Therefore, K. oryziphila NP19 was demonstrated to be a potential candidate for use as a plant growth-promoting bioagent and biopesticide for suppressing rice blast.
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Oryza , Enfermedades de las Plantas , Oryza/microbiología , Oryza/crecimiento & desarrollo , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/prevención & control , Raíces de Plantas/microbiología , Raíces de Plantas/crecimiento & desarrollo , Esporas Fúngicas , Hojas de la Planta/microbiología , Ascomicetos/patogenicidad , Plantones/microbiología , Plantones/crecimiento & desarrollo , Agentes de Control Biológico/farmacología , Peroxidasa/metabolismoRESUMEN
BACKGROUND: In the face of contemporary climatic vulnerabilities and escalating global temperatures, the prevalence of maydis leaf blight (MLB) poses a potential threat to maize production. This study endeavours to discern marker-trait associations and elucidate the candidate genes that underlie resistance to MLB in maize by employing a diverse panel comprising 336 lines. The panel was screening for MLB across four environments, employing standard artificial inoculation techniques. Genome-wide association studies (GWAS) and haplotype analysis were conducted utilizing a total of 128,490 SNPs obtained from genotyping-by-sequencing (GBS). RESULTS: GWAS identified 26 highly significant SNPs associated with MLB resistance, among the markers examined. Seven of these SNPs, reported in novel chromosomal bins (9.06, 5.01, 9.01, 7.04, 4.06, 1.04, and 6.05) were associated with genes: bzip23, NAGS1, CDPK7, aspartic proteinase NEP-2, VQ4, and Wun1, which were characterized for their roles in diminishing fungal activity, fortifying defence mechanisms against necrotrophic pathogens, modulating phyto-hormone signalling, and orchestrating oxidative burst responses. Gene mining approach identified 22 potential candidate genes associated with SNPs due to their functional relevance to resistance against necrotrophic pathogens. Notably, bin 8.06, which hosts five SNPs, showed a connection to defense-regulating genes against MLB, indicating the potential formation of a functional gene cluster that triggers a cascade of reactions against MLB. In silico studies revealed gene expression levels exceeding ten fragments per kilobase million (FPKM) for most genes and demonstrated coexpression among all candidate genes in the coexpression network. Haplotype regression analysis revealed the association of 13 common significant haplotypes at Bonferroni ≤ 0.05. The phenotypic variance explained by these significant haplotypes ranged from low to moderate, suggesting a breeding strategy that combines multiple resistance alleles to enhance resistance to MLB. Additionally, one particular haplotype block (Hap_8.3) was found to consist of two SNPs (S8_152715134, S8_152460815) identified in GWAS with 9.45% variation explained (PVE). CONCLUSION: The identified SNPs/ haplotypes associated with the trait of interest contribute to the enrichment of allelic diversity and hold direct applicability in Genomics Assisted Breeding for enhancing MLB resistance in maize.
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Resistencia a la Enfermedad , Estudio de Asociación del Genoma Completo , Enfermedades de las Plantas , Polimorfismo de Nucleótido Simple , Zea mays , Zea mays/genética , Zea mays/microbiología , Resistencia a la Enfermedad/genética , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/genética , India , Haplotipos , Hojas de la Planta/genética , Hojas de la Planta/microbiología , Sitios de Carácter Cuantitativo , FenotipoRESUMEN
Epiphytic microbes are those that live for some or all of their life cycle on the surface of plant leaves. Leaf surfaces are a topologically complex, physicochemically heterogeneous habitat that is home to extensive, mixed communities of resident and transient inhabitants from all three domains of life. In this review, we discuss the origins of leaf surface microbes and how different biotic and abiotic factors shape their communities. We discuss the leaf surface as a habitat and microbial adaptations which allow some species to thrive there, with particular emphasis on microbes that occupy the continuum between epiphytic specialists and phytopathogens, groups which have considerable overlap in terms of adapting to the leaf surface and between which a single virulence determinant can move a microbial strain. Finally, we discuss the recent findings that the wheat pathogenic fungus Zymoseptoria tritici spends a considerable amount of time on the leaf surface, and ask what insights other epiphytic organisms might provide into this pathogen, as well as how Z. tritici might serve as a model system for investigating plant-microbe-microbe interactions on the leaf surface.