RESUMEN
In plants, a local infection can lead to systemic acquired resistance (SAR) through increased production of salicylic acid (SA). For many years, the identity of the mobile signal and its direct transduction mechanism for systemic SA synthesis in initiating SAR have been debated. We found that in Arabidopsis thaliana, after a local infection, the conserved cysteine residue of the transcription factor CCA1 HIKING EXPEDITION (CHE) undergoes sulfenylation in systemic tissues, which enhances its binding to the promoter of the SA-synthesis gene ISOCHORISMATE SYNTHASE1 (ICS1) and increases SA production. Furthermore, hydrogen peroxide (H2O2) produced through NADPH oxidases is the mobile signal that sulfenylates CHE in a concentration-dependent manner. Accumulation of SA and the previously reported signal molecules, such as N-hydroxypipecolic acid (NHP), then form a signal amplification loop to establish SAR.
Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Peróxido de Hidrógeno , Enfermedades de las Plantas , Ácido Salicílico , Factores de Transcripción , Arabidopsis/genética , Arabidopsis/microbiología , Arabidopsis/inmunología , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Peróxido de Hidrógeno/metabolismo , Ácido Salicílico/metabolismo , Factores de Transcripción/metabolismo , Factores de Transcripción/genética , Enfermedades de las Plantas/microbiología , Resistencia a la Enfermedad/genética , Regiones Promotoras Genéticas , Transferasas Intramoleculares/metabolismo , Transferasas Intramoleculares/genética , NADPH Oxidasas/metabolismo , NADPH Oxidasas/genética , Regulación de la Expresión Génica de las Plantas , Cisteína/metabolismo , Transducción de Señal , Pseudomonas syringaeRESUMEN
Plant pathogens pose a high risk of yield losses and threaten food security. Technological and scientific advances have improved our understanding of the molecular processes underlying host-pathogen interactions, which paves the way for new strategies in crop disease management beyond the limits of conventional breeding. Cross-family transfer of immune receptor genes is one such strategy that takes advantage of common plant immune signalling pathways to improve disease resistance in crops. Sensing of microbe- or host damage-associated molecular patterns (MAMPs/DAMPs) by plasma membrane-resident pattern recognition receptors (PRR) activates pattern-triggered immunity (PTI) and restricts the spread of a broad spectrum of pathogens in the host plant. In the model plant Arabidopsis thaliana, the S-domain receptor-like kinase LIPOOLIGOSACCHARIDE-SPECIFIC REDUCED ELICITATION (AtLORE, SD1-29) functions as a PRR, which senses medium-chain-length 3-hydroxylated fatty acids (mc-3-OH-FAs), such as 3-OH-C10:0, and 3-hydroxyalkanoates (HAAs) of microbial origin to activate PTI. In this study, we show that ectopic expression of the Brassicaceae-specific PRR AtLORE in the solanaceous crop species Solanum lycopersicum leads to the gain of 3-OH-C10:0 immune sensing without altering plant development. AtLORE-transgenic tomato shows enhanced resistance against Pseudomonas syringae pv. tomato DC3000 and Alternaria solani NL03003. Applying 3-OH-C10:0 to the soil before infection induces resistance against the oomycete pathogen Phytophthora infestans Pi100 and further enhances resistance to A. solani NL03003. Our study proposes a potential application of AtLORE-transgenic crop plants and mc-3-OH-FAs as resistance-inducing biostimulants in disease management.
Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Resistencia a la Enfermedad , Ácidos Grasos , Enfermedades de las Plantas , Solanum lycopersicum , Solanum lycopersicum/microbiología , Solanum lycopersicum/inmunología , Solanum lycopersicum/genética , Arabidopsis/inmunología , Arabidopsis/microbiología , Arabidopsis/genética , Resistencia a la Enfermedad/genética , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/inmunología , Ácidos Grasos/metabolismo , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Pseudomonas syringae/patogenicidad , Inmunidad de la Planta , Plantas Modificadas GenéticamenteRESUMEN
Phytochromes (Phys) are a divergent cohort of bili-proteins that detect light through reversible interconversion between dark-adapted Pr and photoactivated Pfr states. While our understandings of downstream events are emerging, it remains unclear how Phys translate light into an interpretable conformational signal. Here, we present models of both states for a dimeric Phy with histidine kinase (HK) activity from the proteobacterium Pseudomonas syringae, which were built from high-resolution cryo-EM maps (2.8-3.4-Å) of the photosensory module (PSM) and its following signaling (S) helix together with lower resolution maps for the downstream output region augmented by RoseTTAFold and AlphaFold structural predictions. The head-to-head models reveal the PSM and its photointerconversion mechanism with strong clarity, while the HK region is interpretable but relatively mobile. Pr/Pfr comparisons show that bilin phototransformation alters PSM architecture culminating in a scissoring motion of the paired S-helices linking the PSMs to the HK bidomains that ends in reorientation of the paired catalytic ATPase modules relative to the phosphoacceptor histidines. This action apparently primes autophosphorylation enroute to phosphotransfer to the cognate DNA-binding response regulator AlgB which drives quorum-sensing behavior through transient association with the photoreceptor. Collectively, these models illustrate how light absorption conformationally translates into accelerated signaling by Phy-type kinases.
Asunto(s)
Proteínas Bacterianas , Histidina Quinasa , Fitocromo , Pseudomonas syringae , Transducción de Señal , Histidina Quinasa/metabolismo , Histidina Quinasa/química , Histidina Quinasa/genética , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Fitocromo/metabolismo , Fitocromo/química , Pseudomonas syringae/metabolismo , Modelos Moleculares , Microscopía por Crioelectrón , Conformación Proteica , Multimerización de Proteína , Fotorreceptores Microbianos/metabolismo , Fotorreceptores Microbianos/química , Fotorreceptores Microbianos/genética , LuzRESUMEN
Plants possess cell surface-localized immune receptors that detect microbe-associated molecular patterns (MAMPs) and initiate defenses that provide effective resistance against microbial pathogens. Many MAMP-induced signaling pathways and cellular responses are known, yet how pattern-triggered immunity (PTI) limits pathogen growth in plants is poorly understood. Through a combined metabolomics and genetics approach, we discovered that plant-exuded proline is a virulence-inducing signal and nutrient for the bacterial pathogen Pseudomonas syringae, and that MAMP-induced depletion of proline from the extracellular spaces of Arabidopsis leaves directly contributes to PTI against P. syringae. We further show that MAMP-induced depletion of extracellular proline requires the amino acid transporter Lysine Histidine Transporter 1 (LHT1). This study demonstrates that depletion of a single extracellular metabolite is an effective component of plant induced immunity. Given the important role for amino acids as nutrients for microbial growth, their depletion at sites of infection may be a broadly effective means for defense against many pathogens.
Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Reconocimiento de Inmunidad Innata , Enfermedades de las Plantas , Inmunidad de la Planta , Pseudomonas syringae , Sistemas de Transporte de Aminoácidos Básicos/metabolismo , Sistemas de Transporte de Aminoácidos Básicos/genética , Arabidopsis/inmunología , Arabidopsis/microbiología , Arabidopsis/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/inmunología , Regulación de la Expresión Génica de las Plantas/inmunología , Reconocimiento de Inmunidad Innata/genética , Metabolómica , Moléculas de Patrón Molecular Asociado a Patógenos/metabolismo , Moléculas de Patrón Molecular Asociado a Patógenos/inmunología , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/inmunología , Inmunidad de la Planta/genética , Hojas de la Planta/microbiología , Hojas de la Planta/metabolismo , Hojas de la Planta/inmunología , Prolina/metabolismo , Pseudomonas syringae/inmunología , Pseudomonas syringae/patogenicidad , Transducción de Señal , VirulenciaRESUMEN
Disease tolerance is an essential defense strategy against pathogens, alleviating tissue damage regardless of pathogen multiplication. However, its genetic and molecular basis remains largely unknown. Here, we discovered that protein condensation at the endoplasmic reticulum (ER) regulates disease tolerance in Arabidopsis against Pseudomonas syringae. During infection, Hematopoietic protein-1 (HEM1) and Bax-inhibitor 1 (BI-1) coalesce into ER-associated condensates facilitated by their phase-separation behaviors. While BI-1 aids in clearing these condensates via autophagy, it also sequesters lipid-metabolic enzymes within condensates, likely disturbing lipid homeostasis. Consequently, mutations in hem1, which hinder condensate formation, or in bi-1, which prevent enzyme entrapment, enhance tissue-damage resilience, and preserve overall plant health during infection. These findings suggest that the ER is a crucial hub for maintaining cellular homeostasis and establishing disease tolerance. They also highlight the potential of engineering disease tolerance as a defense strategy to complement established resistance mechanisms in combating plant diseases.
Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Resistencia a la Enfermedad , Retículo Endoplásmico , Enfermedades de las Plantas , Pseudomonas syringae , Arabidopsis/microbiología , Arabidopsis/inmunología , Arabidopsis/genética , Arabidopsis/metabolismo , Retículo Endoplásmico/metabolismo , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/inmunología , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Pseudomonas syringae/patogenicidad , AutofagiaRESUMEN
The choline-glycine betaine pathway plays an important role in bacterial survival in hyperosmotic environments. Osmotic activation of the choline transporter BetT promotes the uptake of external choline for synthesizing the osmoprotective glycine betaine. Here, we report the cryo-electron microscopy structures of Pseudomonas syringae BetT in the apo and choline-bound states. Our structure shows that BetT forms a domain-swapped trimer with the C-terminal domain (CTD) of one protomer interacting with the transmembrane domain (TMD) of a neighboring protomer. The substrate choline is bound within a tryptophan prism at the central part of TMD. Together with functional characterization, our results suggest that in Pseudomonas species, including the plant pathogen P. syringae and the human pathogen Pseudomonas aeruginosa, BetT is locked at a low-activity state through CTD-mediated autoinhibition in the absence of osmotic stress, and its hyperosmotic activation involves the release of this autoinhibition.
Asunto(s)
Proteínas Bacterianas , Colina , Microscopía por Crioelectrón , Proteínas de Transporte de Membrana , Proteínas de Transporte de Membrana/metabolismo , Proteínas de Transporte de Membrana/química , Colina/metabolismo , Colina/química , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/química , Pseudomonas syringae/metabolismo , Modelos Moleculares , Osmorregulación , Presión Osmótica , Betaína/metabolismo , Conformación Proteica , Unión Proteica , Relación Estructura-Actividad , Dominios ProteicosRESUMEN
Although RNA structures play important roles in regulating gene expression, the mechanism and function of mRNA folding in plant bacterial pathogens remain elusive. Therefore, we perform dimethyl sulfate sequencing (DMS-seq) on the Pseudomonas syringae under nutrition-rich and -deficient conditions, revealing that the mRNA structure changes substantially in the minimal medium (MM) that tunes global translation efficiency (TE), thereby inducing virulence. This process is led by the increased expression of hfq, which is directly activated by transcription regulators RpoS and CysB. The co-occurrence of Hfq and RpoS in diverse bacteria and the deep conservation of Hfq Y25 is critical for RNA-mediated regulation and implicates the wider biological importance of mRNA structure and feedback loops in the control of global gene expression.
Asunto(s)
Regulación Bacteriana de la Expresión Génica , Proteína de Factor 1 del Huésped , Pseudomonas syringae , Transcriptoma , Proteína de Factor 1 del Huésped/metabolismo , Proteína de Factor 1 del Huésped/genética , Virulencia/genética , Transcriptoma/genética , Pseudomonas syringae/patogenicidad , Pseudomonas syringae/genética , Pseudomonas syringae/metabolismo , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/genética , Factor sigma/metabolismo , Factor sigma/genética , ARN Mensajero/metabolismo , ARN Mensajero/genética , ARN Bacteriano/genética , ARN Bacteriano/metabolismo , Enfermedades de las Plantas/microbiologíaRESUMEN
RNase R (encoded by the rnr gene) is a highly processive 3' â 5' exoribonuclease essential for the growth of the psychrotrophic bacterium Pseudomonas syringae Lz4W at low temperature. The cell death of a rnr deletion mutant at low temperature has been previously attributed to processing defects in 16S rRNA, defective ribosomal assembly, and inefficient protein synthesis. We recently showed that RNase R is required to protect P. syringae Lz4W from DNA damage and oxidative stress, independent of its exoribonuclease activity. Here, we show that the processing defect in 16S rRNA does not cause cell death of the rnr mutant of P. syringae at low temperature. Our results demonstrate that the rnr mutant of P. syringae Lz4W, complemented with a RNase R deficient in exoribonuclease function (RNase RD284A), is defective in 16S rRNA processing but can grow at 4 °C. This suggested that the processing defect in ribosomal RNAs is not a cause of the cold sensitivity of the rnr mutant. We further show that the rnr mutant accumulates copies of the indigenous plasmid pLz4W that bears a type II toxin-antitoxin (TA) system (P. syringae antitoxin-P. syringae toxin). This phenotype was rescued by overexpressing antitoxin psA in the rnr mutant, suggesting that activation of the type II TA system leads to cold sensitivity of the rnr mutant of P. syringae Lz4W. Here, we report a previously unknown functional relationship between the cold sensitivity of the rnr mutant and a type II TA system in P. syringae Lz4W.
Asunto(s)
Proteínas Bacterianas , Pseudomonas syringae , ARN Ribosómico 16S , Sistemas Toxina-Antitoxina , Pseudomonas syringae/metabolismo , Pseudomonas syringae/genética , ARN Ribosómico 16S/genética , ARN Ribosómico 16S/metabolismo , Sistemas Toxina-Antitoxina/genética , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/genética , Frío , Exorribonucleasas/metabolismo , Exorribonucleasas/genética , Mutación , Toxinas Bacterianas/metabolismo , Toxinas Bacterianas/genéticaRESUMEN
Biological control is a promising approach to enhance pathogen and pest control to ensure high productivity in cash crop production. Therefore, PGPR biofertilizers are very suitable for application in the cultivation of tea plants (Camellia sinensis) and tobacco, but it is rarely reported so far. In this study, production of a consortium of three strains of PGPR were applied to tobacco and tea plants. The results demonstrated that plants treated with PGPR exhibited enhanced resistance against the bacterial pathogen Pseudomonas syringae (PstDC3000). The significant effect in improving the plant's ability to resist pathogen invasion was verified through measurements of oxygen activity, bacterial colony counts, and expression levels of resistance-related genes (NPR1, PR1, JAZ1, POD etc.). Moreover, the application of PGPR in the tea plantation showed significantly reduced population occurrences of tea green leafhoppers (Empoasca onukii Matsuda), tea thrips (Thysanoptera:Thripidae), Aleurocanthus spiniferus (Quaintanca) and alleviated anthracnose disease in tea seedlings. Therefore, PGPR biofertilizers may serve as a viable biological control method to improve tobacco and tea plant yield and quality. Our findings revealed part of the mechanism by which PGPR helped improve plant biostresses resistance, enabling better application in agricultural production.
Asunto(s)
Nicotiana , Control Biológico de Vectores , Enfermedades de las Plantas , Pseudomonas syringae , Animales , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/prevención & control , Nicotiana/microbiología , Pseudomonas syringae/fisiología , Control Biológico de Vectores/métodos , Camellia sinensis/microbiología , Camellia sinensis/crecimiento & desarrollo , Insectos/microbiología , Thysanoptera/microbiología , Resistencia a la Enfermedad , Desarrollo de la Planta , Agentes de Control Biológico , Hemípteros/microbiologíaRESUMEN
Ice-nucleating proteins (INpro) trigger the freezing of supercooled water droplets relevant to atmospheric, biological, and technological applications. The high ice nucleation activity of INpro isolated from the bacteria Pseudomonas syringae could be linked to the aggregation of proteins at the bacterial membrane or at the air-water interface (AWI) of droplets. Here, we imaged freezing onsets, providing direct evidence of these proposed mechanisms. High-speed cryo-microscopy identified the onset location of freezing in droplets between two protein-repellent glass slides. INpro from sterilized P. syringae (Snomax) statistically favored nucleation at the AWI of the droplets. Removing cellular fragments by filtration or adding surfactants increased the frequency of nucleation events at the AWI. On the other hand, cultivated intact bacteria cells or lipid-free droplets nucleated ice without an affinity to the AWI. Overall, we provide visual evidence that INpro from P. syringae trigger freezing at hydrophobic interfaces, such as the AWI or the bacterial membrane, with important mechanistic implications for applications of INpro.
Asunto(s)
Congelación , Interacciones Hidrofóbicas e Hidrofílicas , Pseudomonas syringae , Pseudomonas syringae/metabolismo , Pseudomonas syringae/química , Proteínas de la Membrana Bacteriana Externa/química , Proteínas de la Membrana Bacteriana Externa/metabolismo , Hielo , Proteínas Bacterianas/química , Proteínas Bacterianas/metabolismoRESUMEN
Plants withstand pathogen attacks by recruiting beneficial bacteria to the rhizosphere and passing their legacy on to the next generation. However, the underlying mechanisms involved in this process remain unclear. In our study, we combined microbiomic and transcriptomic analyses to reveal how the rhizosphere microbiome assembled through multiple generations and defense-related genes expressed in Arabidopsis thaliana under pathogen attack stress. Our results showed that continuous exposure to the pathogen Pseudomonas syringae pv tomato DC3000 led to improved growth and increased disease resistance in a third generation of rps2 mutant Arabidopsis thaliana. It could be attributed to the enrichment of specific rhizosphere bacteria, such as Bacillus and Bacteroides. Pathways associated with plant immunity and growth in A. thaliana, such as MAPK signaling pathways, phytohormone signal transduction, ABC transporter proteins, and flavonoid biosynthesis, were activated under the influence of rhizosphere bacterial communities. Our findings provide a scientific basis for explaining the relationship between beneficial microbes and defense-related gene expression. Understanding microbial communities and the mechanisms involved in plant responses to disease can contribute to better plant management and reduction of pesticide use.
Asunto(s)
Arabidopsis , Resistencia a la Enfermedad , Enfermedades de las Plantas , Pseudomonas syringae , Rizosfera , Arabidopsis/microbiología , Arabidopsis/genética , Arabidopsis/inmunología , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/inmunología , Resistencia a la Enfermedad/genética , Microbiota , Bacterias/genética , Bacterias/clasificación , Bacterias/metabolismo , Bacterias/aislamiento & purificación , Microbiología del Suelo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Adaptación Fisiológica , Raíces de Plantas/microbiología , Raíces de Plantas/genética , Raíces de Plantas/inmunología , Raíces de Plantas/metabolismo , Regulación de la Expresión Génica de las PlantasRESUMEN
Receptor-like cytoplasmic kinases (RLCKs) represent a distinct class of receptor-like kinases crucial for various aspects of plant biology, including growth, development, and stress responses. This study delves into the characterization of RLCK VII-8 members within cucurbits, particularly in melon, examining both structural features and the phylogenetic relationships of these genes/proteins. The investigation extends to their potential involvement in disease resistance by employing ectopic overexpression in Arabidopsis. The promoters of CmRLCK VII-8 genes harbor multiple phytohormone- and stress-responsive cis-acting elements, with the majority (excluding CmRLCK39) displaying upregulated expression in response to defense hormones and fungal infection. Subcellular localization studies reveal that CmRLCK VII-8 proteins predominantly reside on the plasma membrane, with CmRLCK29 and CmRLCK30 exhibiting additional nuclear distribution. Notably, Arabidopsis plants overexpressing CmRLCK30 manifest dwarfing and delayed flowering phenotypes. Overexpression of CmRLCK27, CmRLCK30, and CmRLCK34 in Arabidopsis imparts enhanced resistance against Botrytis cinerea and Pseudomonas syringae pv. tomato DC3000, concomitant with the strengthened expression of defense genes and reactive oxygen species accumulation. The CmRLCK VII-8 members actively participate in chitin- and flg22-triggered immune responses. Furthermore, CmRLCK30 interacts with CmMAPKKK1 and CmARFGAP, adding a layer of complexity to the regulatory network. In summary, this functional characterization underscores the regulatory roles of CmRLCK27, CmRLCK30, and CmRLCK34 in immune responses by influencing pathogen-induced defense gene expression and ROS accumulation.
Asunto(s)
Arabidopsis , Botrytis , Resistencia a la Enfermedad , Regulación de la Expresión Génica de las Plantas , Enfermedades de las Plantas , Proteínas de Plantas , Pseudomonas syringae , Arabidopsis/genética , Arabidopsis/microbiología , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/inmunología , Resistencia a la Enfermedad/genética , Botrytis/fisiología , Botrytis/patogenicidad , Pseudomonas syringae/fisiología , Pseudomonas syringae/patogenicidad , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Cucurbitaceae/microbiología , Cucurbitaceae/genética , Filogenia , Plantas Modificadas GenéticamenteRESUMEN
WRKY transcription factors are essential for coping with various biotic stresses. Pseudomonas syringae pv. actinidiae (Psa)-induced kiwifruit canker is a major problem restricting kiwifruit yield. Nevertheless, it's unclear how the kiwifruit WRKY genes respond to Psa. Through genome-wide identification, 112 WRKY members were found in 'Hongyang' genome in this work. Promoter analysis revealed that there were many cis-acting elements associated with stress responses in the AcWRKY gene's promoter region. According to transcriptomic analysis, 90 of the AcWRKY genes were differently expressed following Psa, salicylic acid (SA), or methyl jasmonate (MeJA) treatments. Almost all group III WRKYs were responsive to at least one of these treatments, with tissue-specific expression patterns. Quantitative RT-PCR study provided more evidence that Psa and SA treatments significantly induced the expression of the group III WRKY gene AcWRKY94, whereas MeJA treatment repressed it. AcWRKY94 was a transcriptionally active protein localized in the nucleus. Transient overexpression of AcWRKY94 in the leaves of 'Hongyang' enhanced the resistance of kiwifruit to Psa. Overexpression of AcWRKY94 in kiwifruit callus remarkably promoted the expression of PR and JAZ genes associated with SA and JA signals, respectively. These data imply that AcWRKY94 controls the signaling pathway dependent on SA and JA, thereby enhancing resistance to Psa. Taken together, this study establishes the basis for functional research on WRKY genes and provides important information for elucidating the resistance mechanism of kiwifruit canker disease.
Asunto(s)
Actinidia , Regulación de la Expresión Génica de las Plantas , Enfermedades de las Plantas , Proteínas de Plantas , Pseudomonas syringae , Factores de Transcripción , Actinidia/microbiología , Actinidia/genética , Pseudomonas syringae/patogenicidad , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Enfermedades de las Plantas/microbiología , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Ciclopentanos/metabolismo , Ciclopentanos/farmacología , Oxilipinas/farmacología , Oxilipinas/metabolismo , Acetatos/farmacología , Ácido Salicílico/metabolismo , Ácido Salicílico/farmacología , Frutas/microbiología , Frutas/genética , Resistencia a la Enfermedad/genética , Regiones Promotoras Genéticas/genéticaRESUMEN
The most effective strategy for managing wheat bacterial blight caused by Pseudomonas syringae pv. syringae is believed to be the use of resistant cultivars. Researching the correlation between molecular markers and stress resistance can expedite the plant breeding process. The current study aims to evaluate the response of 27 bread wheat cultivars to bacterial blight disease in order to identify resistant and susceptible cultivars and to pinpoint ISSR molecular markers associated with bacterial blight resistance genes. ISSR markers are recommended for assessing a plant's disease resistance. This experiment is focused on identifying ISSR molecular markers linked to bacterial blight resistance. After applying the bacterial solution to the leaves, we performed sampling to determine the infection percentage in the leaves at different intervals (7, 14, and 18 days after spraying). In most cultivars, the average leaf infection percentage decreased 18 days after spraying on young leaves. However, in some cultivars such as Niknegad, Darab2, and Zarin, leaf infection increased in older leaves and reached up to 100% necrosis. In our study, 12 ISSR primers generated a total of 170 bands, with 156 being polymorphic. The primers F10 and F5 showed the highest polymorphism, while the F7 primer exhibited the lowest polymorphism. Cluster analysis grouped these cultivars into four categories. The resistant group included Qods, Omid, and Atrak cultivars, while the semi-resistant and susceptible groups comprised the rest of the cultivars. Through binary logistic analysis, we identified three Super oxide dismutase-related genes that contribute to plant resistance to bacterial blight. These genes were linked to the F3, F5, and F12 primers in regions I (1500 bp), T (1000 bp), and G (850 bp), respectively. We also identified seven susceptibility-associated genes. Atrak, Omid, and Qods cultivars exhibited resistance against bacterial blight, and three genes associated with this resistance were linked to the F3, F5, and F12 primers. These markers can be used for screening or transferring tolerance to other wheat cultivars in breeding programs.
Asunto(s)
Resistencia a la Enfermedad , Enfermedades de las Plantas , Pseudomonas syringae , Triticum , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/genética , Triticum/genética , Triticum/microbiología , Resistencia a la Enfermedad/genética , Pseudomonas syringae/fisiología , Marcadores Genéticos , Hojas de la Planta/microbiología , Hojas de la Planta/genética , Modelos LogísticosRESUMEN
Bacterial diseases are one of the most common issues that result in crop loss worldwide, and the increasing usage of chemical pesticides has caused the occurrence of resistance in pathogenic bacteria and environmental pollution problems. Nanomaterial mediated gene silencing is starting to display powerful efficiency and environmental friendliness for improving plant disease resistance. However, the internalization of nanomaterials and the physiological mechanisms behind nano-improved plant disease resistance are still rarely understood. We engineered the polyethyleneimine (PEI) functionalized gold nanoparticles (PEI-AuNPs) with fluorescent properties and ROS scavenging activity to act as siRNA delivery platforms. Besides the loading, protection, and delivery of nucleic acid molecules in plant mature leaf cells by PEI-AuNPs, its fluorescent property further enables the traceability of the distribution of the loaded nucleic acid molecules in cells. Additionally, the PEI-AuNPs-based RNAi delivery system successfully mediated the silencing of defense-regulated gene AtWRKY1. Compared to control plants, the silenced plants performed better resistance to Pseudomonas syringae, showing a reduced bacterial number, decreased ROS content, increased antioxidant enzyme activities, and improved chlorophyll fluorescence performance. Our results showed the advantages of AuNP-based RNAi technology in improving plant disease resistance, as well as the potential of plant nanobiotechnology to protect agricultural production.
Asunto(s)
Resistencia a la Enfermedad , Oro , Nanopartículas del Metal , Enfermedades de las Plantas , Pseudomonas syringae , ARN Interferente Pequeño , Especies Reactivas de Oxígeno , Oro/química , Nanopartículas del Metal/química , Especies Reactivas de Oxígeno/metabolismo , Enfermedades de las Plantas/microbiología , Polietileneimina/química , Silenciador del Gen , Arabidopsis/genéticaRESUMEN
Photorespiratory serine hydroxymethyltransferases (SHMTs) are important enzymes of cellular one-carbon metabolism. In this study, we investigated the potential role of SHMT6 in Arabidopsis thaliana. We found that SHMT6 is localized in the nucleus and expressed in different tissues during development. Interestingly SHMT6 is inducible in response to avirulent, virulent Pseudomonas syringae and to Fusarium oxysporum infection. Overexpression of SHMT6 leads to larger flowers, siliques, seeds, roots, and consequently an enhanced overall biomass. This enhanced growth was accompanied by increased stomatal conductance and photosynthetic capacity as well as ATP, protein, and chlorophyll levels. By contrast, a shmt6 knockout mutant displayed reduced growth. When challenged with Pseudomonas syringae pv tomato (Pst) DC3000 expressing AvrRpm1, SHMT6 overexpression lines displayed a clear hypersensitive response which was characterized by enhanced electrolyte leakage and reduced bacterial growth. In response to virulent Pst DC3000, the shmt6 mutant developed severe disease symptoms and becomes very susceptible, whereas SHMT6 overexpression lines showed enhanced resistance with increased expression of defense pathway associated genes. In response to Fusarium oxysporum, overexpression lines showed a reduction in symptoms. Moreover, SHMT6 overexpression lead to enhanced production of ethylene and lignin, which are important components of the defense response. Collectively, our data revealed that SHMT6 plays an important role in development and defense against pathogens.
Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Resistencia a la Enfermedad , Etilenos , Fusarium , Glicina Hidroximetiltransferasa , Lignina , Enfermedades de las Plantas , Pseudomonas syringae , Arabidopsis/genética , Arabidopsis/microbiología , Etilenos/metabolismo , Lignina/metabolismo , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Pseudomonas syringae/fisiología , Fusarium/fisiología , Fusarium/patogenicidad , Enfermedades de las Plantas/microbiología , Glicina Hidroximetiltransferasa/genética , Glicina Hidroximetiltransferasa/metabolismo , Resistencia a la Enfermedad/genética , Regulación de la Expresión Génica de las Plantas , Plantas Modificadas GenéticamenteRESUMEN
Research initiatives undertaken in response to disease outbreaks accelerate our understanding of microbial evolution, mechanisms of virulence and resistance, and plant-pathogen coevolutionary interactions. The emergence and global spread of Pseudomonas syringae pv. actinidiae (Psa) on kiwifruit (Actinidia chinensis) showed that there are parallel paths to host adaptation and antimicrobial resistance evolution, accelerated by the movement of mobile elements. Significant progress has been made in identifying type 3 effectors required for virulence and recognition in A. chinensis and Actinidia arguta, broadening our understanding of how host-mediated selection shapes virulence. The rapid development of Actinidia genomics after the Psa3 pandemic began has also generated new insight into molecular mechanisms of immunity and resistance gene evolution in this recently domesticated, nonmodel host. These findings include the presence of close homologs of known resistance genes RPM1 and RPS2 as well as the novel expansion of CCG10-NLRs (nucleotide-binding leucine-rich repeats) in Actinidia spp. The advances and approaches developed during the pandemic response can be applied to new pathosystems and new outbreak events.
Asunto(s)
Actinidia , Interacciones Huésped-Patógeno , Enfermedades de las Plantas , Pseudomonas syringae , Enfermedades de las Plantas/microbiología , Pseudomonas syringae/genética , Actinidia/microbiología , Virulencia , Evolución MolecularRESUMEN
ε-Poly-l-lysine (ε-PL) is an effective antimicrobial peptide for controlling fungal plant diseases, exhibiting significant antifungal activity and safety. Despite its known efficacy, the potential of ε-PL in combating plant bacterial diseases remains underexplored. This study evaluated the effectiveness of ε-PL and its nanomaterial derivative in managing tomato bacterial spot disease caused by Pseudomonas syringae pv. tomato. Results indicated that ε-PL substantially inhibited the growth of Pseudomonas syringae pv. tomato. Additionally, when ε-PL was loaded onto attapulgite (encoded as ATT@PL), its antibacterial effect was significantly enhanced. Notably, the antibacterial efficiency of ATT@PL containing 18.80 µg/mL ε-PL was even close to that of 100 µg/mL pure ε-PL. Further molecular study results showed that, ATT@PL stimulated the antioxidant system and the salicylic acid signaling pathway in tomatoes, bolstering the plants disease resistance. Importantly, the nanocomposite demonstrated no negative effects on both seed germination and plant growth, indicating its safety and aligning with sustainable agricultural practices. This study not only confirmed the effectiveness of ε-PL in controlling tomato bacterial spot disease, but also introduced an innovative high antibacterial efficiency ε-PL composite with good bio-safety. This strategy we believe can also be used in improving other bio-pesticides, and has high applicability in agriculture practice.
Asunto(s)
Antibacterianos , Enfermedades de las Plantas , Polilisina , Pseudomonas syringae , Compuestos de Silicona , Solanum lycopersicum , Pseudomonas syringae/efectos de los fármacos , Solanum lycopersicum/microbiología , Polilisina/farmacología , Polilisina/química , Antibacterianos/farmacología , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/prevención & control , Compuestos de Silicona/farmacología , Compuestos de Silicona/química , Compuestos de MagnesioRESUMEN
Tomato (Solanum lycopersicum) is one of the world's most important food crops, and as such, its production needs to be protected from infectious diseases that can significantly reduce yield and quality. Here, we survey the effector-triggered immunity (ETI) landscape of tomato against the bacterial pathogen Pseudomonas syringae. We perform comprehensive ETI screens in five cultivated tomato varieties and two wild relatives, as well as an immunodiversity screen on a collection of 149 tomato varieties that includes both wild and cultivated varieties. The screens reveal a tomato ETI landscape that is more limited than what was previously found in the model plant Arabidopsis thaliana. We also demonstrate that ETI eliciting effectors can protect tomato against P. syringae infection when the effector is delivered by a non-virulent strain either prior to or simultaneously with a virulent strain. Overall, our findings provide a snapshot of the ETI landscape of tomatoes and demonstrate that ETI can be used as a biocontrol treatment to protect crop plants.
Asunto(s)
Enfermedades de las Plantas , Inmunidad de la Planta , Pseudomonas syringae , Solanum lycopersicum , Solanum lycopersicum/microbiología , Solanum lycopersicum/inmunología , Pseudomonas syringae/inmunología , Pseudomonas syringae/patogenicidad , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/inmunología , Arabidopsis/inmunología , Arabidopsis/microbiología , Proteínas de Plantas/inmunología , Virulencia , Regulación de la Expresión Génica de las Plantas , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/inmunologíaRESUMEN
Various metabolites, including phytohormones, phytoalexins, and amino acids, take part in the plant immune system. Herein, we analyzed the effects of L-methionine (Met), a sulfur-containing amino acid, on the plant immune system in tomato. Treatment with low concentrations of Met enhanced the resistance of tomato to a broad range of diseases caused by the hemi-biotrophic bacterial pathogen Pseudomonas syringae pv. tomato (Pst) and the necrotrophic fungal pathogen Botrytis cinerea (Bc), although it did not induce the production of any antimicrobial substances against these pathogens in tomato leaf tissues. Analyses of gene expression and phytohormone accumulation indicated that Met treatment alone did not activate the defense signals mediated by salicylic acid, jasmonic acid, and ethylene. However, the salicylic acid-responsive defense gene and the jasmonic acid-responsive gene were induced more rapidly in Met-treated plants after infection with Pst and Bc, respectively. These findings suggest that low concentrations of Met have a priming effect on the phytohormone-mediated immune system in tomato.