RESUMEN
Anthracnose caused by Colletotrichum scovillei is a significant disease of pepper, including in postharvest stage. Bacillus species represent a potential microbial resource for controlling postharvest plant diseases. Here, a strain HG-8-2 was obtained and identified as Bacillus velezensis through morphological, biochemical, physiological, and molecular analyses. The culture filtrate showed highly antifungal activity against C. scovillei both in vitro and on pepper fruit. Crude lipopeptide extracts, which had excellent stability, could effectively inhibit mycelial growth of C. scovillei with an EC50 value of 28.48 ± 1.45 µg mL-1 and inhibited conidial germination. Pretreatment with the extracts reduced the incidence and lesion size of postharvest anthracnose on pepper fruit. Analysis using propidium iodide staining, malondialdehyde content detection and scanning electron microscope observation suggested that the crude lipopeptide extracts harbored antifungal activity by damaging cell membranes and mycelial structures. The RNA-seq analysis conducted on C. scovillei samples treated with the extracts, as compared to untreated samples, revealed significant alterations in the expression of multiple genes involved in protein biosynthesis. Overall, these results demonstrated that B. velezensis HG-8-2 and its crude lipopeptide extracts exhibit highly antagonistic ability against C. scovillei, thereby offering an effective biological agent for the control of anthracnose in pepper fruit.
Asunto(s)
Bacillus , Capsicum , Colletotrichum , Frutas , Enfermedades de las Plantas , Colletotrichum/efectos de los fármacos , Colletotrichum/crecimiento & desarrollo , Capsicum/microbiología , Bacillus/genética , Bacillus/metabolismo , Bacillus/fisiología , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/prevención & control , Frutas/microbiología , Antifúngicos/farmacología , Antifúngicos/metabolismo , Esporas Fúngicas/efectos de los fármacos , Esporas Fúngicas/crecimiento & desarrollo , Lipopéptidos/farmacología , Lipopéptidos/metabolismo , Micelio/crecimiento & desarrollo , Micelio/efectos de los fármacos , Agentes de Control Biológico/farmacologíaRESUMEN
Knowledge is scarce to what extent environmental drivers and native symbiotic fungi in soil induce abrupt (short-term), systemic (multiple traits), or specific (a subset of traits) shifts in C3 plants' ecophysiological/mycorrhizal responses. We cultivated an emblematic native C3 species (Capsicum annuum var. glabriusculum, "Chiltepín") to look at how the extreme heat of the Sonoran desert, sunlight regimes (low = 2, intermediate = 15, high = 46 mol m2 d-1) and density of native arbuscular mycorrhizal fungi in soil (low AMF = 1% v/v, high AMF = 100% v/v), drive shifts on mycorrhizal responses through multiple functional traits (106 traits). The warming thresholds were relentlessly harsh even under intensive shade (e.g. superheat maximum thresholds reached ranged between 47-63°C), and several pivotal traits were synergistically driven by AMF (e.g. photosynthetic capacity, biomass gain/allometry, and mycorrhizal colonization traits); whereas concurrently, sunlight regimes promoted most (76%) alterations in functional acclimation traits in the short-term and opposite directions (e.g. survival, phenology, photosynthetic, carbon/nitrogen economy). Multidimensional reduction analysis suggests that the AMF promotes a synergistic impact on plants' phenotypic integration and functional plasticity in response to sunlight regimes; however, complex relationships among traits suggest that phenotypic variation determines the robustness degree of ecophysiological/mycorrhizal phenotypes between/within environments. Photosynthetic canopy surface expansion, Rubisco activity, photosynthetic nitrogen allocation, carbon gain, and differential colonization traits could be central to plants' overall ecophysiological/mycorrhizal fitness strengthening. In conclusion, we found evidence that a strong combined effect among environmental factors in which AMF are key effectors could drive important trade-offs on plants' ecophysiological/mycorrhizal fitness in the short term.
Asunto(s)
Clima Desértico , Micorrizas , Fenotipo , Micorrizas/fisiología , Capsicum/microbiología , Capsicum/fisiología , Capsicum/efectos de la radiación , Fotosíntesis/fisiología , Simbiosis/fisiología , Luz Solar , BiomasaRESUMEN
Effective microorganisms (EM) might alleviate deterioration of soil environmental quality and yield decline of pepper (Capsicum annuum) caused by continuous replanting and imbalanced fertilizer application in Xinjiang. We investigated the effects of applying EM microbial agent on the growth of pepper plants, yield, soil nutrient content, soil enzyme activity, and rhizosphere eukaryotic community. The results showed that the application of EM microbial agent increased plant height, stem diameter, leaf length, leaf width and root length by 22.6%, 35.3%, 33.3%, 29.7% and 15.1%, respectively. It also increased fruit width, individual fruit weight, and yield by 5.3%, 42.9%, and 74.7%, respectively. After the application of EM microbial agent, the levels of soil available nitrogen increased by 10.2% and 5.8% during the flowering and maturity stages, respectively. Similarly, available phosphorus increased by 10.4% and 13.4%, respectively. The soil sucrase activity was increased by 40.7%, 14.6%, and 9.3% during the seedling, flowering, and maturity stages, respectively. Urease activity was also increased by 7.9%, 10.2%, and 11.5%, respectively. Furthermore, the application of EM microbial agent increased soil peroxidase activity by 16.8% and 44.6% at flowering and maturity stages, respectively. The application of microbial agent significantly altered the ß-diversity of the rhizosphere eukaryotic community in pepper plants. Specifically, microbial agent increased the relative abundances of populations belonging to Enchytraeus and Sminthurides genera, which could contribute to soil improvement and nutrient cycling. Compared to the CK, the relative abundance of pathogenic microorganisms including Olpidium and Aplanochytrium genera decreased by 98.0% and 89.3%, and the relative abundance of the Verticillium decreased to 0. These results demonstrated that EM microbial agent could increase soil nutrient content, enhance soil enzyme activity, and reduce soil pathogenic fungi in the pepper cultivation areas of Xinjiang, thus achieving beneficial effects on pepper growth and fruit yield.
Asunto(s)
Capsicum , Rizosfera , Microbiología del Suelo , Capsicum/crecimiento & desarrollo , Capsicum/microbiología , China , Suelo/química , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/microbiología , Raíces de Plantas/metabolismoRESUMEN
Fluoxapiprolin, a novel piperidinyl thiazole isoxazoline fungicide, was developed by Bayer Crop Science in 2012. Despite its well-documented inhibitory activity against plant pathogenic oomycetes such as Phytophthora capsici and Phytophthora infestans, limited information regarding its antifungal spectrum and protective and curative activity is available. Fluoxapiprolin exhibited strong inhibitory activity against Phytophthora spp. and several Pythium spp., with EC50 values ranging from 2.12 × 10-4 to 2.92 µg/mL. It was much more effective against P. capsici in inhibiting mycelial growth, sporangium production, and cystospore germination than at reducing zoospore release. Moreover, fluoxapiprolin displayed both protective and curative activity against P. capsici infection in pepper plants under greenhouse conditions, with systemic translocation capability confirmed by High Performance Liquid Chromatography (HPLC) analysis. The results demonstrated the strong inhibitory activity of fluoxapiprolin against economically important plant oomycete pathogens, including Phytophthora spp. and several Pythium spp., and its certain translocation activity in pepper plants.
Asunto(s)
Capsicum , Fungicidas Industriales , Phytophthora , Enfermedades de las Plantas , Fungicidas Industriales/farmacología , Phytophthora/efectos de los fármacos , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/prevención & control , Capsicum/microbiología , Capsicum/efectos de los fármacos , Oomicetos/efectos de los fármacos , Pythium/efectos de los fármacosRESUMEN
BACKGROUND: The fall armyworm (FAW, Spodoptera frugiperda) is a polyphagous pest known for causing significant crop damage. The gut microbiota plays a pivotal role in influencing the biology, physiology and adaptation of the host. However, understanding of the taxonomic composition and functional characteristics of the gut microbiota in FAW larvae fed on different host plants remains limited. METHODS: This study utilized metagenomic sequencing to explore the structure, function and antibiotic resistance genes (ARGs) of the gut microbiota in FAW larvae transferred from an artificial diet to four distinct host plants: maize, sorghum, tomato and pepper. RESULTS: The results demonstrated significant variations in gut microbiota structure among FAW larvae fed on different host plants. Firmicutes emerged as the dominant phylum, with Enterococcaceae as the dominant family and Enterococcus as the prominent genus. Notably, Enterococcus casseliflavus was frequently observed in the gut microbiota of FAW larvae across host plants. Metabolism pathways, particularly those related to carbohydrate and amino acid metabolism, played a crucial role in the adaptation of the FAW gut microbiota to different host plants. KEGG orthologs associated with the regulation of the peptide/nickel transport system permease protein in sorghum-fed larvae and the 6-phospho-ß-glucosidase gene linked to glycolysis/gluconeogenesis as well as starch and sucrose metabolism in pepper-fed larvae were identified. Moreover, the study identified the top 20 ARGs in the gut microbiota of FAW larvae fed on different host plants, with the maize-fed group exhibiting the highest abundance of vanRC. CONCLUSIONS: Our metagenomic sequencing study reveals significant variations in the gut microbiota composition and function of FAW larvae across diverse host plants. These findings underscore the intricate co-evolutionary relationship between hosts and their gut microbiota, suggesting that host transfer profoundly influences the gut microbiota and, consequently, the adaptability and pest management strategies for FAW.
Asunto(s)
Bacterias , Microbioma Gastrointestinal , Larva , Metagenómica , Sorghum , Spodoptera , Zea mays , Animales , Spodoptera/microbiología , Spodoptera/genética , Larva/microbiología , Microbioma Gastrointestinal/genética , Zea mays/microbiología , Bacterias/clasificación , Bacterias/genética , Bacterias/aislamiento & purificación , Sorghum/microbiología , Solanum lycopersicum/microbiología , Capsicum/microbiología , MetagenomaRESUMEN
Small secreted peptides (SSPs) are essential for defense mechanisms in plant-microbe interactions, acting as danger-associated molecular patterns (DAMPs). Despite the first discovery of SSPs over three decades ago, only a limited number of SSP families, particularly within Solanaceae plants, have been identified due to inefficient approaches. This study employed comparative genomics screens with Solanaceae proteomes (tomato, tobacco, and pepper) to discover a novel SSP family, SolP. Bioinformatics analysis suggests that SolP may serve as an endogenous signal initiating the plant PTI response. Interestingly, SolP family members from tomato, tobacco, and pepper share an identical sequence (VTSNALALVNRFAD), named SlSolP12 (also referred to as NtSolP15 or CaSolP1). Biochemical and phenotypic analyses revealed that synthetic SlSolP12 peptide triggers multiple defense responses: ROS burst, MAPK activation, callose deposition, stomatal closure, and expression of immune defense genes. Furthermore, SlSolP12 enhances systemic resistance against Botrytis cinerea infection in tomato plants and interferes with classical peptides, flg22 and Systemin, which modulate the immune response. Remarkably, SolP12 activates ROS in diverse plant species, such as Arabidopsis thaliana, soybean, and rice, showing a broad spectrum of biological activities. This study provides valuable approaches for identifying endogenous SSPs and highlights SlSolP12 as a novel DAMP that could serve as a useful target for crop protection.
Asunto(s)
Botrytis , Genómica , Enfermedades de las Plantas , Inmunidad de la Planta , Proteínas de Plantas , Solanum lycopersicum , Solanum lycopersicum/inmunología , Solanum lycopersicum/genética , Solanum lycopersicum/microbiología , Proteínas de Plantas/genética , Proteínas de Plantas/inmunología , Proteínas de Plantas/metabolismo , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/inmunología , Enfermedades de las Plantas/genética , Inmunidad de la Planta/genética , Péptidos/inmunología , Péptidos/química , Resistencia a la Enfermedad/genética , Resistencia a la Enfermedad/inmunología , Regulación de la Expresión Génica de las Plantas , Nicotiana/inmunología , Nicotiana/genética , Nicotiana/microbiología , Nicotiana/metabolismo , Capsicum/inmunología , Capsicum/genética , Capsicum/microbiología , Capsicum/químicaRESUMEN
AIMS: This study aimed to evaluate the potential of endophytic plant growth-promoting bacterium (PGPB), Pseudomonas putida A32, to mitigate drought stress in two bell pepper genotypes, Amfora 19 and Amfora 26, and to assess the genotype-specific responses to bacterial treatment. METHODS AND RESULTS: The isolate P. putida A32 was selected for its remarkable beneficial properties, exhibiting 13 out of 14 traits tested. Under drought conditions, Amfora 26 showed increased relative water content and decreased H2O2 and malondialdehyde following bacterial treatment, while Amfora 19 exhibited enhanced growth parameters but responded less to bacterial treatment regarding drought parameters. However, Amfora 19 displayed inherent drought tolerance mechanisms, as indicated by lower stress parameters compared to Amfora 26. CONCLUSIONS: The study emphasizes the importance of genotype-specific responses to PGPB treatment and the mechanisms of drought tolerance in peppers. Pseudomonas putida A32 effectively mitigated drought stress in both genotypes, with differential responses influenced by plant genotype. Our study confirmed our initial hypothesis that Amfora 19, as a genotype tolerant to biotic stress, is also more tolerant to abiotic stress. Understanding these interactions is crucial for the development of customized strategies to improve plant productivity and tolerance to drought.
Asunto(s)
Capsicum , Sequías , Genotipo , Pseudomonas putida , Estrés Fisiológico , Pseudomonas putida/genética , Pseudomonas putida/fisiología , Capsicum/microbiología , Capsicum/genética , Endófitos/genética , Endófitos/fisiología , Peróxido de Hidrógeno/metabolismo , Malondialdehído/metabolismoRESUMEN
BACKGROUND: Bacterial spot of pepper (BSP), caused by four different Xanthomonas species, primarily X. euvesicatoria (Xe), poses a significant challenge in pepper cultivation. Host resistance is considered the most important approach for BSP control, offering long-term protection and sustainability. While breeding for resistance to BSP for many years focused on dominant R genes, introgression of recessive resistance has been a more recent focus of breeding programs. The molecular interactions underlying recessive resistance remain poorly understood. RESULTS: In this study, transcriptomic analyses were performed to elucidate defense responses triggered by Xe race P6 infection by two distinct pepper lines: the Xe-resistant line ECW50R containing bs5, a recessive resistance gene that confers resistance to all pepper Xe races, and the Xe-susceptible line ECW. The results revealed a total of 3357 upregulated and 4091 downregulated genes at 0, 1, 2, and 4 days post-inoculation (dpi), with the highest number of differentially expressed genes (DEGs) observed at 2 dpi. Pathway analysis highlighted DEGs in key pathways such as plant-pathogen interaction, MAPK signaling pathway, plant hormone signal transduction, and photosynthesis - antenna proteins, along with cysteine and methionine metabolism. Notably, upregulation of genes associated with PAMP-Triggered Immunity (PTI) was observed, including components like FLS2, Ca-dependent pathways, Rboh, and reactive oxygen species (ROS) generation. In support of these results, infiltration of ECW50R leaves with bacterial suspension of Xe led to observable hydrogen peroxide accumulation without a rapid increase in electrolyte leakage, suggestive of the absence of Effector-Triggered Immunity (ETI). Furthermore, the study confirmed that bs5 does not disrupt the effector delivery system, as evidenced by incompatible interactions between avirulence genes and their corresponding dominant resistant genes in the bs5 background. CONCLUSION: Overall, these findings provide insights into the molecular mechanisms underlying bs5-mediated resistance in pepper against Xe and suggest a robust defense mechanism in ECW50R, primarily mediated through PTI. Given that bs5 provides early strong response for resistance, combining this resistance with other dominant resistance genes will enhance the durability of resistance to BSP.
Asunto(s)
Capsicum , Resistencia a la Enfermedad , Perfilación de la Expresión Génica , Enfermedades de las Plantas , Xanthomonas , Capsicum/genética , Capsicum/microbiología , Capsicum/inmunología , Resistencia a la Enfermedad/genética , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/genética , Regulación de la Expresión Génica de las Plantas , TranscriptomaRESUMEN
In the eastern coastal regions of Odisha, wilt caused by Fusarium oxysporum f. sp.capsici is an extremely damaging disease in chilli. This disease is very difficult to manage with chemical fungicides since it is soil-borne in nature. The natural rhizosphere soil of the chilli plant was used to isolate and test bacterial antagonists for their effectiveness and ability to promote plant growth. Out of the fifty-five isolates isolated from the rhizosphere of healthy chilli plants, five isolates, namely Iso 01, Iso 17, Iso 23, Iso 24, and Iso 32, showed their highly antagonistic activity against F. oxysporum f. sp. capsici under in vitro. In a dual culture, Iso 32 (73.3%) and Iso 24 (71.5%) caused the highest level of pathogen inhibition. In greenhouse trials, artificially inoculated chilli plants treated with Iso 32 (8.8%) and Iso 24 (10.2%) had decreased percent disease incidence (PDI), with percent disease reduction over control of 85.6% and 83.3%, respectively. Iso 32 and Iso 24 treated chilli seeds have shown higher seed vigor index of 973.7 and 948.8, respectively, as compared to untreated control 636.5. Furthermore, both the isolates significantly increased plant height as well as the fresh and dry weight of chilli plants under the rolled paper towel method. Morphological, biochemical, and molecular characterization identified Bacillus amyloliquefaciens (MH491049) as the key antagonist. This study demonstrates that rhizobacteria, specifically Iso 32 and Iso 24, can effectively protect chilli plants against Fusarium wilt while promoting overall plant development. These findings hold promise for sustainable and eco-friendly management of Fusarium wilt in chilli cultivation.
Asunto(s)
Fusarium , Enfermedades de las Plantas , Rizosfera , Microbiología del Suelo , Fusarium/aislamiento & purificación , Fusarium/patogenicidad , Fusarium/efectos de los fármacos , Fusarium/crecimiento & desarrollo , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/prevención & control , Capsicum/microbiología , Capsicum/crecimiento & desarrollo , Antibiosis/fisiología , Desarrollo de la PlantaRESUMEN
The drought can cause a decrease in food production and loss of biodiversity. In northern Mexico, an arid region, the chiltepin grows as a semi-domesticated crop that has been affected in its productivity and yield. An alternative to mitigate the effect of drought and aid in its conservation could be using Plant Growth-Promoting Bacteria (PGPB). The present study evaluated the capacity of native Bacillus spp., isolated from arid soils, as PGPBs and drought stress tolerance inducers in chiltepin under controlled conditions. Chiltepin seeds and seedlings were inoculated with native strains of Bacillus spp. isolated from arid soils, evaluating germination, vegetative, and drought stress tolerance parameters. The PGPBs improved vegetative parameters such as height, stem diameter, root length, and slenderness index in vitro. B. cereus (Bc25-7) improved in vitro survival of stressed seedlings by 68% at -1.02 MPa. Under greenhouse conditions, seedlings treated with PGPBs exhibited increases in root length (9.6%), stem diameter (13.68%), leaf fresh weight (69.87%), and chlorophyll content (38.15%). Bc25-7 alleviated severe water stress symptoms (7 days of water retention stress), and isolates B. thuringiensis (Bt24-4) and B. cereus (Bc25-7, and Bc30-2) increased Relative Water Content (RWC) by 51%. Additionally, the treated seeds showed improved germination parameters with a 46.42% increase in Germination Rate (GR). These findings suggest that using PGPBs could be an alternative to mitigate the effect of drought on chiltepin.
Asunto(s)
Bacillus , Capsicum , Sequías , Plantones , Capsicum/crecimiento & desarrollo , Capsicum/microbiología , Capsicum/fisiología , Bacillus/fisiología , Plantones/crecimiento & desarrollo , Plantones/microbiología , Estrés Fisiológico , Germinación , Semillas/crecimiento & desarrollo , Semillas/microbiología , Microbiología del Suelo , Raíces de Plantas/microbiología , Raíces de Plantas/crecimiento & desarrollo , MéxicoRESUMEN
Fresh produce is traditionally labeled with plastic price lookup (PLU) stickers that are attached to the produce surface using edible glue. However, both the stickers and glue are environmental contaminants, and the stickers can still easily detach from the produce surface during handling and disrupt traceability. An alternative method of labeling, the CO2 laser-labeling technology (LLT), has been gaining attention in recent years. However, engraving Quick Response (QR) code using LLT is unique, and the performance of this technology varies from produce item to produce item, and information on its effects on postharvest quality, microbial safety, and economic feasibility has not been reported. The objectives of this study were to investigate the effect of laser-labeling technology on (1) postharvest quality, (2) microbial safety, and (3) economic analysis of this technology. Three horticultural crops, 'Red Delicious' apple (Malus pumila), green bell pepper (Capsicum annuum), and cucumber (Cucumis sativus) were procured from a local grocery store. Each produce was engraved with a Quick Response (QR) code or 6-digit alphanumerical (text) code using the commercially available Trotec Speedy 300 CO2 laser engraver, followed by the application of edible wax. Fresh weight loss for laser-printed produce was higher compared to controls, but no difference in visual quality ratings was observed. The laser-labeled produce was assessed for microbial contamination by artificially inoculating rifampicin-resistant Escherichia coli (E. coli) log10 6 CFU/mL to the labeled fruit. The results showed that the population of rifampicin-resistant E. coli was statistically higher in all three products labeled with text code compared to the nontreated controls. The QR-coded treatments were similar to the controls. The wax application did not affect the microbial attachment on the laser-labeled produce. The CO2 laser labeling technology has the potential for industrial application.
Asunto(s)
Microbiología de Alimentos , Humanos , Seguridad de Productos para el Consumidor , Contaminación de Alimentos/análisis , Dióxido de Carbono , Recuento de Colonia Microbiana , Manipulación de Alimentos , Capsicum/microbiologíaRESUMEN
In this study, the effect of Thymus vulgaris essential oil (TVO) nanoemulsion (NE, 500 mg/L) in combination with ultrasound (ultrasound-NE) on the microbial and physiological quality of green bell pepper was investigated. The TVO-NE droplet size and zeta potential were 84.26 nm and - 0.77 mV, respectively. The minimum inhibitory concentrations of the TVO and TVO-NE against E. coli and S. aureus were about 0.07 and 7 g/L, respectively. The NE-ultrasound treatment exhibited the lowest peroxidase activity and respiration rate with no detrimental effect on texture, total phenolic content, antioxidant activity, pH, and TSS. Although the NE-ultrasound treatment showed the highest weight loss and electrolytic leakage, it exhibited the best visual color and appearance. The NE-ultrasound treatment descended the total viable/mold and yeast counts significantly compared to control. Results showed that treating the bell peppers with NE-ultrasound can result in bell peppers with good postharvest quality and extended shelf life.
Asunto(s)
Capsicum , Escherichia coli , Nanocápsulas , Aceites Volátiles , Staphylococcus aureus , Thymus (Planta) , Thymus (Planta)/química , Aceites Volátiles/farmacología , Aceites Volátiles/química , Capsicum/química , Capsicum/microbiología , Escherichia coli/efectos de los fármacos , Staphylococcus aureus/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Antibacterianos/farmacología , Conservación de Alimentos/métodos , Ultrasonido/métodos , Antioxidantes/farmacología , Ondas Ultrasónicas , EmulsionesRESUMEN
Chromium (Cr) is a well-known environmental pollutant while less information is available on the role of Cr-resistant bacteria in the alleviation of Cr-stress in chili (Capsicum annum L.) plants. Effect of Cr-resistant bacterial strains on growth and Cr uptake by chili plants was investigated. The results revealed that Cr-stress showed a negative effect on germination, photosynthesis, and relative water content but the inoculation ameliorated the plant stress. Chromium-resistant bacterial strains enhanced the shoot and root growth (33% SL, 19.7% RL), shoot and root dry weight (35%, 32.9%), relative water content (32.25%), membrane stability index (46.52%) SPAD value (50.76%), Cr concentration in shoots and roots (19.87 and 18.52 mg kg-1), bioaccumulation and translocation factor (0.396 mgkg-1), and seedling vigor index (40.8%) of plants. Chromium-resistant bacterial strains enhanced the NPK uptake while reduced Cr uptake by plants. The morphological and biochemical examination of rhizobacterial strains (and NM28) resistant to Cr-stress revealed smooth, off-white colonies of bacteria composed of rod-shaped cells which are Gram positive in reaction while negative in catalase activity. High quantities of malic acid were produced by bacterial strains under study i.e. NM8 (926.12 µgmL-2) and NM28 (992.25 µgmL-2). These strains were identified as Bacillus cereus strain NM8 and Bacillus subtilis strain NM28 through 16S rRNA sequencing. Results showed that B. cereus strain NM28 is more effective than B. cereus strain NM8 in promoting the growth of Cr-stressed Chili that might be suitable to develop biofertilizer for sustainable production of vegetables under metal stress.
Asunto(s)
Capsicum , Cromo , Germinación , Capsicum/microbiología , Capsicum/crecimiento & desarrollo , Capsicum/metabolismo , Capsicum/efectos de los fármacos , Cromo/metabolismo , Germinación/efectos de los fármacos , Estrés Fisiológico/efectos de los fármacos , Raíces de Plantas/microbiología , Raíces de Plantas/metabolismo , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/efectos de los fármacos , Bacterias/metabolismo , Bacterias/efectos de los fármacos , Bacterias/genética , Bacterias/crecimiento & desarrollo , Fotosíntesis/efectos de los fármacosRESUMEN
Demequina, commonly found in coastal and marine environments, represents a genus of Actinomycetes. In this study, strains Demequina PMTSA13T and OYTSA14 were isolated from the rhizosphere of Capsicum annuum, leading to the discovery of a novel species, Demequina capsici. Bacteria play a significant role in plant growth, yet there have been no reports of the genus Demequina acting as plant growth-promoting bacteria (PGPB). Comparative genomics analysis revealed ANI similarity values of 74.05-80.63% for PMTSA13T and 74.02-80.54% for OYTSA14, in comparison to various Demequina species. The digital DNA-DNA hybridization (dDDH) values for PMTSA13T ranged from 19 to 39%, and 19.1-38.6% for OYTSA14. Genome annotation revealed the presence of genes associated with carbohydrate metabolism and transport, suggesting a potential role in nutrient cycling and availability for plants. These strains were notably rich in genes related to 'carbohydrate metabolism and transport (G)', according to their Cluster of Orthologous Groups (COG) classification. Additionally, both strains were capable of producing auxin (IAA) and exhibited enzymatic activities for cellulose degradation and catalase. Furthermore, PMTSA13T and OYTSA14 significantly induced the growth of Arabidopsis thaliana seedlings primarily attributed to their capacity to produce IAA, which plays a crucial role in stimulating plant growth and development. These findings shed light on the potential roles of Demequina strains in plant-microbe interactions and agricultural applications. The type strain is Demequina capsici PMTSA13T (= KCTC 59028T = GDMCC 1.4451T), meanwhile OYTSA14 is identified as different strains of Demequina capsici.
Asunto(s)
Capsicum , Filogenia , Rizosfera , Capsicum/microbiología , Capsicum/crecimiento & desarrollo , Microbiología del Suelo , Actinobacteria/genética , Actinobacteria/aislamiento & purificación , Actinobacteria/clasificación , ARN Ribosómico 16S/genética , Genoma Bacteriano , Desarrollo de la PlantaRESUMEN
Tropospheric ozone [O3] is a secondary air pollutant formed from the photochemical oxidation of volatile organic compounds in the presence of nitrogen oxides, and it is one of the most damaging air pollutants to crops. O3 entry into the plant generates reactive oxygen species leading to cellular damage and oxidative stress, leading to decreased primary production and yield. Increased O3 exposure has also been shown to have secondary impacts on plants by altering the incidence and response to plant pathogens. We used the Capsicum annum (pepper)-Xanthomonas perforans pathosystem to investigate the impact of elevated O3 (eO3) on plants with and without exposure to Xanthomonas, using a disease-susceptible and disease-resistant pepper cultivar. Gas exchange measurements revealed decreases in diurnal photosynthetic rate (A') and stomatal conductance ( g s ' ), and maximum rate of electron transport (Jmax) in the disease-resistant cultivar, but no decrease in the disease-susceptible cultivar in eO3, regardless of Xanthomonas presence. Maximum rates of carboxylation (Vc,max), midday A and gs rates at the middle canopy, and decreases in aboveground biomass were negatively affected by eO3 in both cultivars. We also observed a decrease in stomatal sluggishness as measured through the Ball-Berry-Woodrow model in all treatments in the disease-resistant cultivar. We hypothesize that the mechanism conferring disease resistance to Xanthomonas in pepper also renders the plant less tolerant to eO3 stress through changes in stomatal responsiveness. Findings from this study help expand our understanding of the trade-off of disease resistance with abiotic stresses imposed by future climate change.
Asunto(s)
Capsicum , Ozono , Fotosíntesis , Enfermedades de las Plantas , Xanthomonas , Capsicum/microbiología , Capsicum/fisiología , Capsicum/efectos de los fármacos , Ozono/farmacología , Fotosíntesis/efectos de los fármacos , Xanthomonas/fisiología , Xanthomonas/efectos de los fármacos , Enfermedades de las Plantas/microbiología , Resistencia a la Enfermedad , Estrés FisiológicoRESUMEN
Previous work identified a pair of specific effectors AsCEP19 and AsCEP20 in Alternaria solani as contributors to the virulence of A. solani. Here, we constructed AsCEP19 and AsCEP20 deletion mutants in A. solani strain HWC168 to further reveal the effects of these genes on the biology and pathogenicity of A. solani. Deletion of AsCEP19 and AsCEP20 did not affect vegetative growth but did affect conidial maturation, with an increase in the percentage of abnormal conidia produced. Furthermore, we determined the expression patterns of genes involved in the conidiogenesis pathway and found that the regulatory gene abaA was significantly upregulated and chsA, a positive regulator for conidiation, was significantly downregulated in the mutant strains compared to the wild-type strain. These results suggest that AsCEP19 and AsCEP20 indirectly affect the conidial development and maturation of A. solani. Pathogenicity assays revealed significantly impaired virulence of ΔAsCEP19, ΔAsCEP20, and ΔAsCEP19 + AsCEP20 mutants on potato and tomato plants. Moreover, we performed localization assays with green fluorescent protein-tagged proteins in chili pepper leaves. We found that AsCEP19 can specifically localize to the chloroplasts of chili pepper epidermal cells, while AsCEP20 can localize to both chloroplasts and the plasma membrane. Weighted gene co-expression network analysis revealed enrichment of genes of this module in the photosynthesis pathway, with many hub genes associated with chloroplast structure and photosynthesis. These results suggest that chloroplasts are the targets for AsCEP19 and AsCEP20. IMPORTANCE: Alternaria solani is an important necrotrophic pathogen causing potato early blight. Previous studies have provide preliminary evidence that specific effectors AsCEP19 and AsCEP20 contribute to virulence, but their respective functions, localization, and pathogenic mechanisms during the infection process of A. solani remain unclear. Here, we have systematically studied the specific effectors AsCEP19 and AsCEP20 for the first time, which are essential for conidial maturation. The deletion of AsCEP19 and AsCEP20 can significantly impair fungal pathogenicity. Additionally, we preliminarily revealed that AsCEP19 and AsCEP20 target the chloroplasts of host cells. Our findings further enhance our understanding of the molecular mechanisms underlying the virulence of necrotrophic pathogens.
Asunto(s)
Alternaria , Capsicum , Proteínas Fúngicas , Regulación Fúngica de la Expresión Génica , Enfermedades de las Plantas , Esporas Fúngicas , Alternaria/patogenicidad , Alternaria/genética , Alternaria/crecimiento & desarrollo , Alternaria/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Virulencia/genética , Enfermedades de las Plantas/microbiología , Esporas Fúngicas/crecimiento & desarrollo , Esporas Fúngicas/genética , Capsicum/microbiología , Solanum tuberosum/microbiología , Solanum lycopersicum/microbiología , Cloroplastos/metabolismo , Cloroplastos/genética , Hojas de la Planta/microbiologíaRESUMEN
Rhizoctonia solani, the causative agent of sheath blight disease in rice, poses a significant threat to agricultural productivity. Traditional management approaches involving chemical fungicides have been effective but come with detrimental consequences for the ecosystem. This study aimed to investigate sustainable alternatives in the form of antifungal peptides derived from Solanaceous plant species as potential agents against R. solani. Peptide extracts were obtained using an optimized antimicrobial peptide (AMP) extraction method and desalted using the solid-phase extraction technique. The antifungal potential of peptide-rich extracts from Solanum tuberosum and Capsicum annum was assessed through in vitro tests employing the agar well diffusion method. Furthermore, peptide-protein docking analysis was performed on HPEPDOCK and HDOCK server; and molecular dynamics simulations (MDS) of 100 ns period were performed using the Gromacs 2020.4. The results demonstrated significant inhibition zones for both extracts at concentrations of 100 mg/mL. Additionally, the extracts of Solanum tuberosum and Capsicum annum had minimum inhibitory concentrations of 50 mg/mL and 25 mg/mL, respectively with minimum fungicidal concentrations of 25 mg/mL. Insights into the potential mechanisms of key peptides inhibiting R. solani targets were gleaned from in-silico studies. Notably, certain AMPs exhibited favorable free energy of binding against pathogenicity-related targets, including histone demethylase, sortin nexin, and squalene synthase, in protein-peptide docking simulations. Extended molecular dynamics simulations lasting 100 ns and MM-PBSA calculations were performed on select protein-peptide complexes. AMP10 displayed the most favorable binding free energy against all target proteins, with AMP3, AMP12b, AMP6, and AMP15 also exhibiting promising results against specific targets of R. solani. These findings underscore the potential of peptide extracts from S. tuberosum and C. annum as effective antifungal agents against rice sheath blight caused by R. solani.
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Simulación del Acoplamiento Molecular , Simulación de Dinámica Molecular , Oryza , Enfermedades de las Plantas , Rhizoctonia , Oryza/microbiología , Enfermedades de las Plantas/microbiología , Rhizoctonia/efectos de los fármacos , Péptidos Antimicrobianos/farmacología , Péptidos Antimicrobianos/química , Antifúngicos/farmacología , Antifúngicos/química , Antifúngicos/aislamiento & purificación , Solanum tuberosum/microbiología , Extractos Vegetales/química , Extractos Vegetales/farmacología , Solanaceae/química , Pruebas de Sensibilidad Microbiana , Simulación por Computador , Capsicum/microbiología , Capsicum/químicaRESUMEN
BACKGROUND: Several WRKY transcription factors (TFs), including CaWRKY6, CaWRKY22, CaWRKY27, and CaWRKY40 are known to govern the resistance of pepper (Capsicum annuum L.) plants to Ralstonia solanacearum infestation (RSI) and other abiotic stresses. However, the molecular mechanisms underlying these processes remain elusive. METHODS: This study functionally described CaWRKY3 for its role in pepper immunity against RSI. The roles of phytohormones in mediating the expression levels of CaWRKY3 were investigated by subjecting pepper plants to 1 mM salicylic acid (SA), 100 µM methyl jasmonate (MeJA), and 100 µM ethylene (ETH) at 4-leaf stage. A virus-induced gene silencing (VIGS) approach based on the Tobacco Rattle Virus (TRV) was used to silence CaWRKY3 in pepper, and transiently over-expressed to infer its role against RSI. RESULTS: Phytohormones and RSI increased CaWRKY3 transcription. The transcriptions of defense-associated marker genes, including CaNPR1, CaPR1, CaDEF1, and CaHIR1 were decreased in VIGS experiment, which made pepper less resistant to RSI. Significant hypersensitive (HR)-like cell death, H2O2 buildup, and transcriptional up-regulation of immunological marker genes were noticed in pepper when CaWRKY3 was transiently overexpressed. Transcriptional activity of CaWRKY3 was increased with overexpression of CaWRKY6, CaWRKY22, CaWRKY27, and CaWRKY40, and vice versa. In contrast, Pseudomonas syringae pv tomato DC3000 (Pst DC3000) was easily repelled by the innate immune system of transgenic Arabidopsis thaliana that overexpressed CaWRKY3. The transcriptions of defense-related marker genes like AtPR1, AtPR2, and AtNPR1 were increased in CaWRKY3-overexpressing transgenic A. thaliana plants. CONCLUSION: It is concluded that CaWRKY3 favorably regulates phytohormone-mediated synergistic signaling, which controls cell death in plant and immunity of pepper plant against bacterial infections.
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Capsicum , Regulación de la Expresión Génica de las Plantas , Enfermedades de las Plantas , Reguladores del Crecimiento de las Plantas , Inmunidad de la Planta , Proteínas de Plantas , Ralstonia solanacearum , Factores de Transcripción , Ralstonia solanacearum/fisiología , Capsicum/genética , Capsicum/inmunología , Capsicum/microbiología , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/inmunología , Enfermedades de las Plantas/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Reguladores del Crecimiento de las Plantas/metabolismo , Ciclopentanos/metabolismo , Resistencia a la Enfermedad/genética , Oxilipinas/metabolismo , Ácido Salicílico/metabolismo , Etilenos/metabolismo , Silenciador del Gen , Acetatos/farmacologíaRESUMEN
Pepper southern blight, caused by Sclerotium rolfsii, is a devastating soil-borne disease resulting in significant loss to pepper, Capsicum annuum L. production. Here, we isolated an antagonistic bacterial strain XQ-29 with antifungal activity against S. rolfsii from rhizospheric soil of pepper. Combining the morphological and biochemical characteristics with the 16S rDNA sequencing, XQ-29 was identified as Streptomyces griseoaurantiacus. It exhibited an inhibition of 96.83% against S. rolfsii and displayed significant inhibitory effects on Botrytis cinerea, Phytophthora capsica and Rhizoctonia solani. Furthermore, XQ-29 significantly reduced the pepper southern blight by 100% and 70.42% during seedling and growth stages, respectively. The antifungal mechanism involved altering the mycelial morphology, disrupting cell wall and membrane integrity, accompanied by accumulation of reactive oxygen species and lipid peroxidation in S. rolfsii mycelia. Furthermore, XQ-29 promoted growth and stimulated resistance of pepper plants by increasing defense-related enzyme activities and upregulating defense-related genes. Correspondingly, XQ-29 harbors numerous functional biosynthesis gene clusters in its genome, including those for siderophores and melanin production. The metabolic constituents present in the ethyl acetate extracts, which exhibited an EC50 value of 85.48 ± 1.62 µg/mL, were identified using LC-MS. Overall, XQ-29 demonstrates significant potential as a biocontrol agent against southern blight disease.
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Botrytis , Capsicum , Enfermedades de las Plantas , Rhizoctonia , Streptomyces , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/prevención & control , Capsicum/microbiología , Streptomyces/genética , Streptomyces/fisiología , Botrytis/efectos de los fármacos , Botrytis/fisiología , Rhizoctonia/fisiología , Rhizoctonia/efectos de los fármacos , Basidiomycota/fisiología , Phytophthora/fisiología , Phytophthora/efectos de los fármacos , Agentes de Control Biológico/farmacología , Antifúngicos/farmacologíaRESUMEN
Selenium (Se) is one of the fifteen essential nutrients required by the human body. Mycorrhizal microorganisms play a crucial role in enhancing selenium availability in plants. However, limited research exists on the impact of arbuscular mycorrhizal fungi (AMF) on selenium accumulation and transport in pepper plants. This study employed a pot experiment to investigate the changes in pepper plant growth, selenium accumulation, and transformation following inoculation with AMF and varying concentrations of exogenous selenium. The results indicate that exogenous selenium application in pepper has dual effects. At low concentrations (≤8 mg Lâ»1), it promotes growth and nutrient accumulation, whereas high concentrations (>16 mg Lâ»1) inhibit these processes. AMF inoculation positively influences selenium accumulation and transport in peppers, significantly increasing yield per plant by 17.89%, vitamin C content by 67.36%, flavonoid content by 43.26%, capsaicin content by 14.82%, DPPH radical scavenging rate by 18.18%, and ABTS radical scavenging rate by 27.81%. Additionally, it significantly reduces selenocysteine methyltransferase (SMT) enzyme activity, while minimally affecting ATP sulfurylase (ATPS) and adenosyl sulfate reductase (APR) enzyme activities. The combined treatment of AMF and 8 mg Lâ»1 exogenous selenium has been proven to be the most effective for selenium enrichment in peppers, offering new insights into utilizing exogenous selenium and AMF inoculation to enhance selenium content in peppers.