Search Results (104)

Black point (BP) and Fusarium-damaged kernels are common disorders affecting wheat grains worldwide. While the negative impact of Fusarium head blight (FHB) on yield and grain quality is well established, the biological significance of BP remains debated. This study evaluated the effects of BP on yield-related traits and seedling performance of winter wheat and compared them with the effects of FHB. Four winter wheat cultivars (Mercedes, Adina, Steffi, and LG Mocca) were examined under field and laboratory conditions. Fusarium infection was induced by artificial inoculation with Fusarium culmorum, whereas BP was assessed under natural field conditions using non-inoculated control plants. Fusarium infection significantly reduced thousand-grain weight (up to 46%) and grain number per ear (up to 35%). In contrast, BP was not associated with yield reduction. Grain with BP symptoms showed a 10–30% higher thousand-grain weight compared with BP-free grain. Seedlings originating from BP-affected seeds exhibited equal or improved biometric traits and a higher vigor index. Phytopathological analysis showed that Alternaria spp. dominated the endophytic mycoflora of both BP-affected and BP-free seeds. These results indicate that, under the conditions of this study, BP did not negatively affect wheat yield or seedling vigor and differed fundamentally from the damaging effects of FHB, highlighting the importance of distinguishing BP from Fusarium-related damage in wheat production. Full article

Net form net blotch disease, caused by Pyrenophora teres f. teres (Ptt), is one of the most destructive barley diseases, resulting in severe yield and grain quality losses worldwide. The increasing prevalence of fungicide-resistant Ptt strains, driven by the pathogen’s high genetic variability, highlights the urgent need for sustainable and eco-friendly disease management strategies. The present study provides novel insights into the use of native seed-borne endophytic bacteria naturally associated with barley as biological control agents against Ptt. Two endophytic bacterial strains isolated from healthy barley seeds were identified based on 16S rRNA gene sequencing as Bacillus subtilis PX491551 and Stenotrophomonas rhizophila PX494419. Their biocontrol potential against Ptt was evaluated through in vitro, greenhouse, and field experiments. In the dual-culture assay, B. subtilis and S. rhizophila inhibited the mycelial growth of Pyrenophora teres f. teres by 64.34% and 50.14%, respectively. Under greenhouse conditions, B. subtilis and S. rhizophila significantly reduced disease severity at the seedling stage, with scores of 2.00 and 4.00, respectively, compared to 9.33 in the untreated control. Beyond disease suppression, both endophytic bacteria markedly enhanced the host’s defense system. S. rhizophila induced the highest accumulation of total soluble phenolics, while B. subtilis significantly increased flavonoid content and boosted higher activities of superoxide dismutase and phenylalanine ammonia-lyase. In contrast, S. rhizophila showed the strongest induction of ascorbate peroxidase activity. Notably, field application of both bacteria consistently reduced net blotch severity over two consecutive growing seasons (2023–2024 and 2024–2025) and considerably improved chlorophyll content, 1000-grain weight, and grain yield. Overall, this study demonstrates that native seed-derived endophytic bacteria not only suppress barley net blotch but also enhance host antioxidant and defense responses, highlighting their potential as effective and sustainable biological control agents for barley disease management. Full article

Bambara groundnut is an underutilized legume with significant potential for enhancing nutrition and food security. However, limited knowledge of its seed systems hinders the development of targeted interventions. This study assessed the Bambara groundnut seed systems and seed quality in Ghana. A semi-structured questionnaire was used to examine seed production, conditioning, and saving practices, while 150 farmer-saved seed samples were evaluated for quality. The findings revealed that the seed system is predominantly informal, with 99% of farmers relying on their own saved seeds, which showed poor germination and emergence. About 54.4% sourced seeds from local markets, and 60.7% recycled seeds for five years or more. Seeds were stored unshelled in polypropylene bags in Tolon and shelled in the Kintampo South and Talensi Districts. Seed selection was primarily based on size (in Tolon) and visible absence of disease symptoms (in Kintampo South and Talensi). An incidence (7.6%) of seed-borne pathogens was recorded, with Aspergillus flavus (38.8%) and A. niger (16.6%) being most prevalent. Other pathogens included Macrophomina phaseolina (11.5%), Rhizopus spp. (6.5%), Curvularia lunata (5.3%), and A. fumigatus (1.9%). This study highlights the need to support community-based seed systems to improve farmers’ access to quality Bambara groundnut seed. Full article

Common bacterial blight (CBB) is a significant disease caused by the seed-borne pathogen Xanthomonas axonopodis pv. phaseoli (Xap), which devastates global bean production. This study evaluated the effects of Bacillus subtilis (Bst26), Lactobacillus plantarum (Lpkb10), their combination (Bst26 + Lpkb10), copper hydroxide (CH), and an untreated control on controlling CBB in three bean cultivars (Göynük, Saltan, and Tezgeldi). Disease incidence (CI), disease severity index (DSI), severity score (SC), area under disease progress curve (AUDPC), and disease control (DC), along with agronomic traits such as plant height, number of primary branches, root length, and fresh root weight, were recorded to assess both infection rates and plant health under each treatment. The findings revealed significant differences in DI, DSI, SC, AUDPC, and DC (p ≤ 0.01) among the bean cultivars for CBB. Among the cultivars, the Bst26 treatment and the combination of Bst26 and Lpkb10 showed the highest control effectiveness, with DI values of 33.11% and 33.46% in Saltan, 35.65% and 44.16% in Göynük, and 37.71% and 42.43% in Tezgeldi, respectively, at 21 days after inoculation (DAI). Bst26 alone and in combination with Lpkb10 effectively controlled CBB, with disease reduction of 56.80% and 46.49% in Göynük, 57.08% and 56.62% in Saltan, and 52.18% and 46.19% in Tezgeldi, respectively. Disease progression was highest in the untreated control, with DI ranging from 77.15% to 82.54% across Göynük, Saltan, and Tezgeldi cultivars. Significant differences (p ≤ 0.01) in plant height, root length, and root weight were observed among treatments and cultivars. Disease parameters were negatively correlated with plant growth traits, and multi-treatment analysis demonstrated that combining bacterial strains effectively reduced disease severity in susceptible cultivars, highlighting their potential for improved CBB management. Full article

Wheat (Triticum aestivum L.) is a crucial global food crop. The intensive crop farming, monoculture cultivation, and impact of climate change affect the susceptibility of wheat cultivars to biotic stresses, mainly caused by soil fungal pathogens, especially those belonging to the genus Fusarium. This situation threatens yield and grain quality through root and crown rot. While conventional chemical fungicides face resistance issues and environmental concerns, biological alternatives like seed priming with natural metabolites are gaining attention. Polyamines, including putrescine, spermidine, and spermine, are attractive priming agents influencing plant development and abiotic stress responses. Spermine in particular shows potential for in vitro antifungal activity against Fusarium. Optimising spermine concentration for seed priming is crucial to maximising protection against Fusarium infection while ensuring robust plant growth. In this research, we explored the potential of the polyamine spermine as a seed treatment to enhance wheat resilience, aiming to identify a sustainable alternative to synthetic fungicides. Our findings revealed that a six-hour seed soak in spermine solutions ranging from 0.5 to 5 mM did not delay germination or seedling growth. In fact, the 5 mM concentration significantly stimulated root weight and length. In complementary in vitro assays, we evaluated the antifungal activity of spermine (0.5–5 mM) against three Fusarium species. The results demonstrated complete inhibition of Fusarium culmorum growth at 5 mM spermine. A less significant effect on Fusarium graminearum and little to no impact on Fusarium oxysporum were found. The performed analysis revealed that the spermine had a fungistatic effect against the pathogen, retarding the mycelium growth of F. culmorum inoculated on the seed surface. A pot experiment with Bulgarian soft wheat cv. Sadovo-1 was carried out to estimate the effect of seed priming with spermine against infection with isolates of pathogenic fungus F. culmorum on plant growth and disease severity. Our results demonstrated that spermine resulted in a reduced distribution of F. culmorum and improved plant performance, as evidenced by the higher fresh weight and height of plants pre-treated with spermine. This research describes the efficacy of spermine seed priming as a novel strategy for managing Fusarium root and crown rot in wheat. Full article

Contaminated seeds pose a major risk in hydroponic systems, as a single contaminated seed can compromise the entire setup. Effective decontamination strategies are essential to control seed-borne pathogens. Pecan shells, a byproduct comprising nearly 50% of the nut’s weight, have demonstrated antimicrobial properties against key pathogens. This study evaluated pecan shell extract (PSE) as a treatment to inactivate Listeria monocytogenes, Escherichia coli O157:H7, and Pseudomonas spp. on lettuce seeds and its effect on germination. Lettuce seeds were inoculated with L. monocytogenes strains (101 M, V7, LCDC, and Scott A) and treated with PSE (1:10 w/v) either by coating in sodium alginate or priming for 6 h (4 °C or room temperature). Hydropriming was used as a control. Additional trials with E. coli and Pseudomonas spp. tested PSE at 1:10, 1:20, and 1:30 w/v ratios. Priming at refrigeration significantly reduced Listeria levels. E. coli priming treatments showed significant reductions at 1:20 and 1:30 w/v. For Pseudomonas, priming at 1:20 showed the highest reduction. PSE priming also enhanced germination (88.3%), outperforming other treatments. These findings suggest PSE is a sustainable and effective seed treatment to reduce microbial contamination and enhance seed germination in hydroponic systems. Full article

A study was conducted to examine the effects of the spray application of nine antifungal products, including microbial-derived fungicides, plant-derived fungicides, and chemical fungicides, on the grass Achnatherum inebrians that was either host to Epichloë gansuensis (E+) or E. gansuensis-free (E−) and that was exposed to Blumeria graminis, the fungal pathogen causing powdery mildew. The Epichloë endophyte is a seed-borne mutualistic biotrophic fungus whose growth is fully synchronized with the host grass. Bl. graminis is a biotrophic pathogen that continually infects leaves and stems via conidia, the formation of appressoria, leading to the presence of haustoria in epidermal cells. Prior to fungicide application, the presence of endophytes significantly increased the resistance of A. inebrians to powdery mildew and was able to increase the chlorophyll content. However, the positive effects of the Epichloë endophyte on the plant were suppressed with the use of some fungicides and the increase in the number of sprays, but the reciprocal relationship between the Epichloë endophyte and the plant was not significantly disrupted. Full article

Climate change, soil degradation, and the spread of seed-borne pathogens pose serious challenges to global food security and agricultural sustainability. Although chemical seed treatment provides pathogen control, it poses environmental and health risks. This review analyses innovative seed treatment technologies, with particular emphasis on ozonation as an ecologically viable alternative. The mechanisms of action of ozone, its effects on seed germination, reduction of microbial contamination, and crop establishment are discussed. Chemical, physical, and biological treatment methods are comparatively evaluated, analyzing their effectiveness, environmental impact, and application limitations. Full article

Rice bakanae disease (RBD), a major threat in rice-cropping nations, can reduce rice yield and quality. As it is a seed-borne disease, effective seed detection is crucial. Loop-mediated isothermal amplification (LAMP) can rapidly and specifically amplify DNA at a constant temperature with high sensitivity. This research uses LAMP to develop rapid RBD pathogen detection systems. Primers were designed targeting the NRPS31 gene of Fusarium fujikuroi and conserved TEF1α sequences of Fusarium asiaticum, Fusarium proliferatum, and Fusarium andiyazi. These reactions at 60 °C for 60 min had a detection limit of 100 pg·μL⁻¹, and LAMP proved applicable in field trials. Full article

Curtobacterium species are increasingly recognized as plant pathogens and soil decomposers, but their prevalence and function as plant endophytes in aerial organs are less clear. In this study, we isolated six endophytic Curtobacterium species from the fruits, flower petals (previously unreported) and stem tissue of plants from diverse environments and examined their general characteristics. We found that all Curtobacterium endophytes belonging to three major Curtobacterium clusters—C. oceanosedimentum (a group not previously recognized as endophytic), C. luteum and C. flaccumfaciens—shared some common features. All or nearly all isolates tested were pigmented, displayed moderate salt tolerance and, surprisingly, were psychrotolerant, being able to grow at 6 °C. The exception was a fruit C. luteum isolate that appears to have evolved thermotolerance (up to 45 °C) instead as a likely adaptation to its environment. All isolates were able to metabolize starch and casein and solubilize inorganic phosphate, indicating conserved secreted hydrolase activity, but only isolates in the C. oceanosedimentum group were able to absorb and metabolize citrate. Finally, all endophytes tested were able to ferment the plant sugars sucrose and fructose, while they differed in their ability to use other sugars. Thus, this study documents common traits and adaptations in various Curtobacterium endophytes, and the presence of these isolates in floral and fruit organs implies the possible seed-borne inheritance of these isolates. Full article

In the process of long-term co-evolution, endophytes and host plants benefit from and interact with each other, resulting in positive effects such as promoting plant growth, enhancing resistance, producing beneficial secondary metabolites, and negative effects such as carrying pathogens and producing toxins. In addition to the vegetative organs, plant seeds are also colonized by diverse endophytes and serve as vectors for the transmission of endophytes across plant generations. Seed endophytes, termed seed-borne endophytes (SBEs), have attracted much attention because these endophytes are involved in the assembly of the plant association microbiome and exert effects on progeny plants through vertical transfer. However, the importance of SBEs may still be underestimated. The present paper reviews the diversity, origin, and vertical transmission of seed endophytes, as well as their interaction and function with hosts, so as to provide a reference for future research and application of seed endophytes. Full article

Bacterial fruit blotch (BFB) is a highly destructive seed-borne and seed-transmitted disease caused by the Gram-negative bacterium Acidovorax citrulli that has caused substantial economic losses for the cucurbit industry in China. Despite its potential for economic damage, little is known about the bacterium’s molecular mechanisms of pathogenicity. Toxin–antitoxin (TA) systems are critical for the bacterial stress response. These systems are composed of two genes, toxin and antitoxin, that encode a stable toxin protein and a labile antitoxin protein, respectively. In this study, the genes for the putative HipBA TA system were identified in A. citrulli genomes through bioinformatic analysis. A series of molecular biology experiments have demonstrated that the HipBA TA system exists in A. citrulli Aac5. Furthermore, the transcription of hipA and hipB in A. citrulli Aac5 were induced by pH stress, chloramphenicol stress, and during plant infection. Overall, our results have revealed an active type II TA system, HipBA, in A. citrulli Aac5, and provided insights into its biological functions. These findings contribute to a better understanding of TA systems in plant pathogens. Full article

A wide range of seed-borne and soil-borne plant pathogens belonging to various fungal and fungal-like species cause pre-emergence seed decay and post-emergence seedling blights of wheat and other small-grain cereal crops. To prevent the death of the seedlings, poor establishment and reduced stand of the crops, extensive crop rotations, planting good-quality seeds and seed treatments with fungicides are used on regular basis. This study is aimed at assessing the efficacy of pre-sowing seed treatments with cold atmospheric plasma for the disinfestation of winter wheat seed from economically important fungal and fungal-like pathogens. Uninoculated or surface-inoculated with Fusarium culmorum, Bipolaris sorokiniana or Pythium ultimum wheat seeds, the cultivar Madara was treated by cold plasma produced either by microwave torch (MW) or underwater diaphragm discharge (UW) with low power at very short treatment times, or remained untreated controls. As per the treatments, the seeds were sown in a ready-to-use growing medium comprising a mixture of light and dark moss peat (w:w) 90–95%, 5–10% perlite and 3–5 kg/m³ CaCO₃, having an electrical conductivity of 40 mS/m, pH (H₂O) of 5.5–6.5 and moisture content of 60–70%, filling in 250 × 250 × 70 mm aluminum flat seed trays (40 grains per tray, four trays per treatment). The plants were cultivated for 45 days in a growth chamber held at (20 ± 2) °C, set to a cycle of 8 h/night and 16 h/day under fluorescent light of 2000–3000 lux intensity. For each replicate, disease incidence (DI) was determined as the total percentage of missing, dead and apparently symptomatic plants. Seed treatment with a microwave plasma torch with a power of 16 W for 40 s significantly (p < 0.001) reduced seedling blights caused by F. culmorum, B. sorokiniana and P. ultimum by 46.8%, 51.0% and 77.3%, respectively, but limited the emergence of wheat seedlings by 15.9% on average. Simultaneously, the effectiveness of underwater discharge seed treatments reached an average of about a 60% reduction of seedling blight caused by F. culmorum and B. sorokiniana and about 37% of the disease caused by P. ultimum. Pre-sowing treatments with a MW plasma torch with an input power of 11 W and treatment time of 60, 90 or 120 s exposure also showed significant (p < 0.001) effects in controlling winter wheat seedling blights caused by the three pathogens. The effectiveness of the treatment increased with increasing the time period of exposure and reached full disease control (>80% reduction) for B. sorokiniana and P. ultimum seedling blights. This study demonstrated that pre-sowing treatment with a microwave plasma torch and underwater diaphragm discharge at a relatively low input power and short exposure time can be used for disinfestation and the effective control of seedling blights in winter wheat caused by seed-borne fungal pathogens, such as Fusarium culmorum and Bipolaris sorokiniana, and fungal-like oomycetes, such as Pythium ultimum. Full article

Pathogenesis from soil- and seed-borne fungi can limit the survival and growth of native seeds and seedlings. Fungicides can combat fungal pathogens, but in some studies, fungicide treatments were ineffective at improving seedling emergence over untreated seed. Such studies suggest that low fungal presence due to dry conditions may be the cause of fungicide ineffectiveness in some years and sites. This study tested whether a fungicide treatment’s effectiveness is indeed related to the amount of fungi in the soil. We compared the emergence and biomass produced from Pseudoroegneria spicata seed that was uncoated, coated with no active ingredient, and fungicide-coated, across five soil treatments promoting different levels of fungal biomass. For uncoated seed, both percent emergence and total biomass of seedlings were highest in autoclaved soil and declined when fungi were present, but the level of fungus did not impact emergence or biomass for fungicide-coated seed. When grown in autoclaved, untreated, or low-fungus soils, percent emergence and total biomass from fungicide-coated seeds were not significantly different from uncoated seeds. However, in medium- and high-fungus soils, the percent emergence and total biomass from fungicide-coated seeds were more than two times greater than uncoated seed (p < 0.05). These results indicate that fungicide treatments can be effective at increasing restoration success for P. spicata, but the effectiveness of the fungicide treatment depends on the microbial environment of the planting site. Full article

The global demand for legumes has grown significantly since the 1960s, due to their high protein content and environmental benefits. However, this growth could also facilitate the spread of seed-borne pathogens like Curtobacterium flaccumfaciens pv. flaccumfaciens (Cff). Cff is a Gram-positive bacterium causing bacterial wilt in common beans and poses substantial challenges in regard to its detection and management, due to its long latent period and xylemic nature. Traditional diagnostic methods have proven insufficient, highlighting the need for innovative approaches. This study explores the potential of volatile organic compounds (VOCs) produced by Cff to be used as diagnostic markers to prevent the spread of seed-borne pathogens. First, we analyzed the VOCs emitted by different Cff strains in vitro, identifying a unique blend of five major VOCs. Subsequently, we verified the presence of these VOCs in vivo in artificially infected Cannellino beans. Phenylmethanol and 2-methoxy-4-vinylphenol emerged as key diagnostic markers, differentiating Cff from other bacterial pathogens of beans, such as Pseudomonas savastanoi pv. phaseolicola and Xanthomonas phaseoli pv. phaseoli. Our findings suggest that VOC fingerprinting offers a non-invasive, effective method for the early detection of Cff, even in asymptomatic seeds. This innovative approach holds significant promise for improving seed-borne disease management and supporting the development of practical diagnostic tools for field applications. Further research should aim to enhance the sensitivity and specificity of VOC-based diagnostics, facilitating the rapid and accurate screening of plant materials at ports of entry. This would contribute to the sustainability and health of leguminous crop production. Full article