Prunus virus T (PrVT; genus Tepovirus, family Betaflexiviridae) is an emerging virus whose impact and distribution remain poorly understood. In this study, a novel isolate, named PrVT Puglia, was identified in sweet cherry (Prunus avium) in southern Italy using high-throughput sequencing (HTS). Its complete genome (6,865 nt) displays the typical Tepovirus organization, encoding a replicase, a movement protein, and a coat protein. The genomic sequence of the PrVT Puglia isolate (PZ377051) showed nucleotide identities ranging from 73.4
Protein hydrolysates (PHs) are emerging as sustainable biostimulants capable of enhancing plant tolerance to biotic and abiotic stresses. In this study, PHs were produced in-house from soybean and pea flours through enzymatic hydrolysis using two proteolytic enzymes, alcalase and papain, yielding four hydrolysates (PH1–PH4). The resulting PHs were characterized in terms of protein content, degree of hydrolysis, and peptide composition. The efficacy of the PHs in protecting table grape berries against Botrytis cinerea, the causal agent of grey mould, was then evaluated on two cultivars, Red Globe and Italia. The soybean hydrolysate obtained with alcalase (PH1), applied at 3.2 mg/mL, was the most effective treatment in both cultivars, reducing disease incidence by up to 90
Phytophthora capsici, causal agent of the foot rot disease, is one of the most devastating phytopathogens affecting black pepper (Piper nigrum L.). In this study, both culture dependent and independent methods were employed to analyse the fungal mycobiome of Piper spp., with a focus on the potential role of fungal endophytes in foot rot suppression. The culture independent analysis (ITS metagenomics) revealed significant compositional differences in the mycobiome of cultivated healthy and diseased Piper nigrum and the foot rot resistant wild one, Piper colubrinum. The rhizomicrobiome and root endophytic microbiome of P. colubrinum were dominated with anti-oomycete genera, particularly Trichoderma which was supported by a culture dependent study. The antagonistic isolates not only produced both volatile and non-volatile compounds that activated their biocontrol properties, but were with plant growth promoting traits also. A promising strain, T. asperellum PCLF1 significantly enhanced the plant growth, reduced the foliar and soil infections by P. capsici and stimulated elevated levels of defense enzymes in black pepper plantlets, confirming its biocontrol potential and plant growth promoting effects. The present study also reports an account of mycobiome associated with healthy and diseased P. nigrum plants, underscoring the potential of fungi in managing the P. capsici infection in black pepper.
Bacterial brown spot caused by Pseudomonas syringae pv. syringae (Pss) and bacterial wilt caused by Curtobacterium flaccumfaciens pv. flaccumfaciens (Cff) are among the most important diseases of bean. This study evaluated plant essential oils (EOs) as potential antimicrobial alternatives. EOs from Zataria multiflora, Achillea wilhelmsii, Prangos ferulacea, Teucrium polium, and Satureja hortensis were extracted by hydrodistillation and tested against Pss and Cff both in vitro and in vivo. Antibacterial activity was assessed using well diffusion and broth microdilution methods for MIC/MBC determination. In the well diffusion assay at 50 µL, S. hortensis, Z. multiflora, P. ferulacea, A. wilhelmsii, and T. polium showed the highest activity against the Pss P2 and the Cff 211. MIC and MBC results for Pss A2 showed that S. hortensis and Z. multiflora were the most potent treatments. A. wilhelmsii and P. ferulacea showed moderate activity, whereas T. polium showed weak activity. For Cff isolate 211, S. hortensis and Z. multiflora were most effective. P. ferulacea and A. wilhelmsii had moderate effects, and T. polium was weak. Population dynamics of Pss and Cff in bean leaves over 12 days post-inoculation were significantly affected by EO type and concentration (p < 0.01), with a significant bacterium × EO interaction. Treatments with Z. multiflora, S. hortensis, and P. ferulacea EOs reduced bacterial populations for all strains by day 12. These three EOs show strong potential for controlling Pss and Cff in beans because of their effective antimicrobial compounds.
Field surveys in fig orchards of Fars Province, Iran, revealed emerging symptoms of branch cankers marked by copper-orange to brown discoloration, necrotic lesions, and subcortical tissue damage in both juvenile and mature branches. Integrated morphological, physiological, molecular, and pathogenicity analyses consistently identified Acremonium egyptiacum (syn. A. sclerotigenum) as the causal agent of this emerging disease. Pathogenicity assays on detached fig shoots and one-year-old saplings confirmed its capacity to induce characteristic dark lesions and internal discoloration, from which the fungus was successfully re-isolated, thereby fulfilling Koch’s postulates. All isolates exhibited pathogenicity, yet significant variation in aggressiveness was evident across four quantified traits. Greenhouse inoculations using wounded-stem and cut-stem methods further substantiated pathogenic potential; the wounded-stem approach elicited more pronounced symptoms, enabling robust multivariate analysis. This method also produced symptom profiles closely aligned with field observations, supporting its selection for subsequent cultivar susceptibility testing and potential host-range evaluations. Multivariate analysis of pathogenicity traits revealed distinct cultivar-level variation in susceptibility. Principal component analysis and hierarchical clustering identified three susceptibility groups, with ‘Payves’ being highly susceptible, while ‘Matti’ and ‘Brown Turkey’ exhibited reduced susceptibility. Potential host range assessments demonstrated the pathogen’s ability to induce wood necrosis in several economically significant fruit and ornamental species, with pistachio remaining asymptomatic, suggesting potential non-host resistance. Clustering analysis classified 15 tested species into four susceptibility categories, with apple, pomegranate, and red mulberry among the most susceptible. The pathogen’s ability to affect species from Lythraceae, Moraceae, and Rosaceae underscores its broad potential host range and lack of specificity. Temperature emerged as a critical determinant of aggressiveness, with the most severe symptoms observed at 20 °C and 25 °C, and minimal activity at 40 °C. These findings offer essential insights for disease forecasting, climate-resilient cultivar selection, and integrated management strategies.
This study investigates the diversity and ochratoxigenic potential of fungi associated with durum wheat (Triticum durum) in Morocco, highlighting possible contamination pathways from field to storage. Ninety-six wheat samples were collected from four distinct bioclimatic regions, yielding 294 fungal isolates. The genera Penicillium and Aspergillus were predominant (43.75
Dry root rot caused by Macrophomina phaseolina is an emerging and highly destructive disease responsible for significant yield losses in groundnut production, particularly in semi-arid tropics regions of the world. The present study aimed to isolate, characterize and evaluate the antagonistic efficacy of bioagents against M. phaseolina via in vitro methods (dual culture, inverted plate and culture filtrate assays) and talc-based formulations of potential Trichoderma and Bacillus isolates under in vivo conditions. A total of sixteen isolates of each fungal and bacterial bioagents were isolated and screened for their inhibitory effects against M. phaseolina. Among these, five Trichoderma isolates (PNT01, PNT05, PNT08, PNT11 and PNT16) and five Bacillus isolates (PNB01, PNB05, PNB10, PNB13, and PNB16) exhibited the highest level of mycelial growth inhibition under in vitro conditions. Molecular characterization revealed that four Trichoderma isolates (PNT01, PNT05, PNT10, and PNT16) were closely related to Trichoderma harzianum species complex, and PNT14 was identical to T. virens. Similarly, the Bacillus isolates PNB05 and PNB10 have similarities with Bacillus subtilis, PNB03 (B. oceanisediminis), PNB13 (B. pacificus), and PNB16 (B. cereus). In the culture filtrate assay, PNT05 (T. harzianum species complex) and PNB10 (B. subtilis) exhibited highest mycelium growth inhibition of M. phaseolina. Field results revealed that the seed treatment combined with soil application of T. harzianum species complex resulted in the maximum reduction in disease inhibition and significant improvement in plant-growth and yield parameters such as germination percentage, shoot length, root length, number of root nodules per plant, number of pods per plant and pod yield followed by seed treatment combined with soil application of B. subtilis. These findings indicate that T. harzianum species complex and B. subtilis may be used as potential biocontrol agents against M. phaseolina, which favours the eco-friendly management of groundnut dry root rot disease.
Foot rot or wilt disease caused by Sclerotium rolfsii Sacc. has emerged as a major constraint to finger millet (Eleusine coracana L. Gaertn.) production in southern India. Reliable artificial inoculation methods are essential for pathogenicity studies and resistance screening however, standardized protocols for finger millet-S. rolfsii pathosystem remain largely unavailable. The present study aimed to develop, optimize and validate artificial inoculation techniques (AITs) for reproducible disease induction under controlled conditions. Extensive field surveys across 60 locations in southern Karnataka revealed considerable spatial variation in foot rot incidence, with the highest mean disease incidence recorded in Mandya district (42.24
Common bacterial blight (CBB) is a major disease of common bean (Phaseolus vulgaris L.), caused by Xanthomonas phaseoli pv. phaseoli (Xpp) and Xanthomonas citri pv. fuscans (Xcf). Despite the relevance of CBB in Italy, genomic data for Italian Xpp strains are currently missing. Here, we present the first complete genome sequence of two Italian Xpp strains, USB771 and DEF699, generated using Oxford Nanopore Technologies (ONT). Long-read sequencing produced high-quality assemblies for both strains, with genome completeness exceeding 98.9
This study aimed to isolate and characterize bacterial strains potentially associated with hairy root disease (HRD) from a tomato greenhouse in Mexico. Bacterial isolates recovered on LB agar were subsequently screened by Gram staining and using semi-selective culture media and biochemical assays targeting Gram-negative bacteria capable of tellurite reduction, alkaline tolerance, erythritol utilization, and 3-ketolactose production. Molecular identification through 16S rDNA gene sequencing revealed five bacterial isolates selected for pathogenicity assays, including Shinella sp. Ar534, Agrobacterium sp. M8R5, Rhizobium sp. M15R5, Asticcacaulis sp. 1M7A3, and Kaistia sp. M6A13. Pathogenicity assays in Phaseolus vulgaris sprouts demonstrated that Shinella sp. Ar534 and Agrobacterium sp. M8R5 induced adventitious root formation on the hypocotyl, averaging 10 and 37 roots per plant, respectively. In tomato seedlings, these strains increased root hair density by 128
Comparative proteomics of wild (Solanum cheesmaniae) and cultivated (S. lycopersicum var. Kashi Aman) tomato species challenged with Alternaria solani revealed differential but distinct molecular responses at protein level against the pathogen. The S. cheesmaniae plants displayed relatively low disease symptoms but were identified with more differentially abundant proteins (DAPs) (321) that were linked to plant defense, stress responses, and growth, in contrast to the cultivated species that showed high disease intensity and less DAPs (183). Multivariate analyses such as PLS-DA demonstrated clear differences in protein composition patterns, reflecting species-specific strategies against pathogen attack. The protein-protein interaction (PPI) network of S. cheesmaniae plant showed more-abundant chaperonins and others into three distinct clusters with multiple hub proteins involved in RNA processing and signal transduction while that of cultivated species centered around energy metabolism (MgATP and MgADP), indicating a more resource-intensive strategy. Cellular localization patterns of more-abundant proteins underscored compartmentalization of proteins across extracellular, cytoplasmic, and organelles in the S. cheesmaniae. Dominance of significantly more-abundant defense, signaling and plant growth-related proteins in pathogen-challenged S. cheesmaniae reflected stronger response against the pathogen. Strong antioxidant enzyme activity in the pathogen inoculated S. cheesmaniae leaves reflected enhanced defense system in the species. The findings indicated that greater diversity and functional enrichment of defense proteins in S. cheesmaniae confer enhanced metabolic flexibility and disease resistance. It further offers insights into the molecular basis of biotic stress tolerance against devastating early blight pathogen.
Bacterial blight (BB) of grapevine produced by pathogen Xanthomonas campestris (Xc) has emerged as an important disease of grapevine in the grape-growing territory of Maharashtra (India), and to manage it, most of the farmers have been using copper compounds and antibiotics. However, frequent use of such chemicals causes resistant strain of pathogen, phytotoxicity, environmental pollution, and human health hazards; hence, to overcome these issues, the goal of the present study is to formulate an eco-friendly and economical formulation ‘Maxicure’ based on the phytochemicals, essential oils, primary metabolites of plants, minerals, and natural emulsifier. We investigate its antibacterial efficacy against the pathogen (Xc) in both in-vitro and in-vivo conditions at distinct concentrations along with 2 antibiotics (streptocycline and kasugamycin), and 3 commercial copper fungicides (copper hydroxide, copper oxychloride and copper sulphate) which are traditionally used by farmers in the management of BB of grapevine. However, it has been observed that Maxicure and Streptocycline strongly inhibit the growth of Xc at the concentration of 2000 and 300 µg mL-1, respectively, under both conditions, while kasugamycin shows moderate activity at 300 µg mL-1 under in vitro conditions. Copper hydroxide, copper oxychloride, and copper sulphate did not show any growth of inhibition at 2000 µg mL− 1 concentration under both the conditions. Therefore, the present study highlights the potential of Maxicure in managing bacterial blight of grapevine as an eco-friendly and sustainable approach to minimize the use of antibiotics and copper compounds, demonstrating its practical usefulness in biological applications.
Fire blight is a bacterial disease of apple and pear caused by Erwinia amylovora and results in serious economic losses worldwide. Although the bactericidal antibiotic streptomycin has been widely studied, comparatively little is known about the population-level responses of E. amylovora to oxytetracycline, a bacteriostatic antibiotic used for fire blight management. In this study, we investigated changes in culturability and physiological subpopulations of E. amylovora following oxytetracycline exposure and evaluated its efficacy under multiple conditions, including nutrient availability, external pH, proton motive force (PMF) perturbation, and antibiotic treatment sequence with streptomycin. Short-term oxytetracycline treatment did not affect the culturability of E. amylovora, whereas long-term treatment caused a gradual decline in culturability. Long-term exposure to oxytetracycline also induced nutrient-dependent physiological shifts in the population. Notably, under nutrient-deficient conditions, the proportion of dead cells increased markedly over time, accompanied by a decrease in viable cells. Viable but nonculturable (VBNC) cells were detected only at a low frequency in samples collected at day 14 under nutrient-deficient conditions. External pH strongly influenced oxytetracycline activity at pH 4.0–5.0 and in immature apple broth resulted in a rapid decline in culturability. Disruption of PMF further accelerated the loss of culturability under nutrient-deficient conditions and was associated with sustained membrane depolarization signals. In sequential antibiotic treatments, oxytetracycline pretreatment reduced the initial bactericidal effect of streptomycin and produced distinct physiological population structures during long-term exposure. Collectively, these results suggest that optimal oxytetracycline efficacy for fire blight control requires consideration of environmental conditions as well as the treatment sequence with streptomycin.
Fire blight, caused by Erwinia amylovora, is a disease linked to host developmental stage, with the highest risk occurring during bloom and early shoot growth. Consequently, the hormonal regulation of flowering, pollination, fruit set, and vegetative growth is considered not only in terms of productivity, but also in terms as a determinant of disease susceptibility. Across these stages, phytohormones function through interconnected regulatory networks that coordinate developmental processes while simultaneously influencing host–pathogen interactions. In modern apple production, these pathways are routinely manipulated through plant growth regulators (PGRs) to optimize productivity; however, such interventions can also alter disease risk by modifying tissue susceptibility, growth dynamics, and the duration of infection windows. This review synthesizes current knowledge on the roles of phytohormones and PGRs in apple growth and development, with emphasis on their implications for fire blight risk, host susceptibility, and disease management. We examine how hormonal regulation of reproductive development influences blossom blight susceptibility, how vegetative growth and canopy architecture shape shoot blight risk, and how these processes are integrated within orchard systems. We further discuss the role of salicylic acid as a key signaling molecule in plant defense and its potential as a component of integrated fire blight management programs. Collectively, these studies demonstrate that fire blight risk is not solely determined by external factors but is also mediated by host hormonal status. Integrating hormonal regulation into fire blight management frameworks represents an opportunity to improve both productivity and resilience in modern apple production systems.
Botrytis cinerea is a prominent necrotrophic pathogen responsible for gray mold disease, affecting a wide range of plant species, including economically vital crops such as tomatoes, grapes, strawberries, etc. Nitric oxide (NO) is considered as a crucial player in plant responses to biotic stress. NO homeostasis is regulated by phytoglobin (Pgb1), a potential scavenger of NO. However, the role of the Pgb1-NO cycle in regulating defense response against B. cinerea remains largely unknown. In the current study, we investigated the defense response of Arabidopsis thaliana against B. cinerea infection using antisense (Pgb1 AS) and overexpression (Pgb1 OE) lines, which produce differential levels of NO. The Pgb1 AS line accumulated higher NO levels and conferred resistance against B. cinerea infection, with reduced ROS levels, reduced cell death, and increased stomatal closure. Conversely, Pgb1 OE showed reduced NO levels accompanied by increased susceptibility. The elevated NO level in Pgb1 AS was associated with increased nitrate reductase (NR) activity and upregulation of NIA1 and NIA2 gene expression. Interestingly, ethylene-mediated defense pathway genes such as ERF1, ACS2, and ACS6 were upregulated while pathogen-related genes such as PR1, PR2, PR5, and NPR1 were downregulated in Pgb1 AS line. The elevated expression of ethylene genes corresponded with the higher ethylene levels in Pgb1 AS. Overall, our results confirmed the crucial role of phytoglobin-modulated NO in defense against B. cinerea infection by activating the ethylene-mediated defense pathway.
Charcoal rot, caused by Macrophomina phaseolina poses a significant threat to sunflower production due to its virulence factors and persistence. In this study we identified three rhizobacteria as Brevundimonas naejangsanensis, Brevundimonas diminuta and Alcaligenes faecalis through 16S rRNA sequencing from Jeddah rhizosphere soil and evaluated their antagonistic activity against M. phaseolina MT023712. These biocontrol isolates inhibited mycelial growth of M. phaseolina calculated by fresh and dry weight reduction (77–88
