Search Results (242)

Tomato crops are treated with high concentrations of synthetic fertilizers and insecticides to increase yields, but the careless use of these chemicals harms the environment and human health and affects plant pathogen resistance. The effect of foliar spray of three concentrations of chitosan (500, 1000, and 2000 mg L⁻¹) on plant growth, yield, fruit quality, and physiological performance in two tomato varieties (Floradade and Candela F1) was studied. Physiological traits such as photosynthesis, chlorophyll content, and leaf area index of the plants were positively affected by chitosan, an effective compound that biostimulates growth, with increases in biomass of organs with respect to the control treatment. Chitosan also improved tomato quality, such as increases in polyphenols, antioxidant capacity, flavonoids, carotenoids, vitamin C, and total soluble solids in both tomato varieties. Finally, yield increased by 76.4% and 65.4% in Floradade and Candela F1, respectively. The responses of tomato plants to chitosan application were different depending on the variety evaluated, indicating a differential response to the biostimulant. The use of chitosan in agriculture is a tool that has no negative effects on plants and the environment and can increase the productive capacity of tomato plants. Full article

Tree diseases affecting Camellia japonica have emerged as a significant threat to the health and longevity of this ornamental tree, particularly in countries where this tree species is widely distributed and cultivated. Among these, Pestalotiopsis spp. have been frequently reported and are considered one of the most impactful fungal pathogens, causing leaf blight or leaf spot, in multiple countries. Understanding the etiology and distribution of these diseases is essential for effective management and conservation of C. japonica populations. The traditional methods based on pathogen isolation and pure culture cultivation for diagnosis of tree diseases are labor intensive and time-consuming. In addition, the frequent coexistence of the major pathogens with other endophytes within a single C. japonica tree, coupled with inconsistent symptom expression and the occurrence of pathogens in asymptomatic hosts, further complicates disease diagnosis. These challenges highlight the urgent need to develop more rapid, accurate, and efficient diagnostic or monitoring tools to improve disease monitoring and management on trees, including C. japonica. To address these challenges, we applied a metagenomic approach to screen fungal communities within C. japonica trees. This method enabled comprehensive detection and characterization of fungal taxa present in symptomatic and asymptomatic tissues. By analyzing the correlation between fungal dominance and symptom expression, we identified key pathogenic taxa associated with disease manifestation. To validate the metagenomic approach, we employed a combined strategy integrating metagenomic screening and traditional fungal isolation to monitor foliar diseases in C. japonica. The correlation between dominant taxa and symptom expression was confirmed. Simultaneously, traditional isolation enabled the identification of a novel species, Pestalotiopsis, as the causal agent of leaf spot disease on C. japonica. In addition to confirming previously known pathogens, our study led to the discovery and preliminary characterization of a novel fungal taxon with pathogenic potential. Our findings provide critical insights into the fungal community of C. japonica and lay the groundwork for developing improved, rapid diagnostic tools for effective disease monitoring and management of tree diseases. Full article

Soilborne diseases cause losses of 45–70% in faba bean in Ethiopia. Studies were undertaken to define soilborne pathogens and their complexes in Ethiopia. First, the severity of root rot was assessed in 150 field sites across seven Ethiopian regions. Soil samples were collected, and the DNA of 29 pests and pathogens was quantified using a commercial quantitative PCR (qPCR) soil testing service. There was a very high incidence rate of Macrophomina phaseolina, as well as Pythium clades F and I. The other detected species in order of incidence included Fusarium redolens, Rhizoctonia solani, Aphanomyces euteiches, Phytophthora megasperma, Sclerotinia sclerotiorum and S. minor, and Verticillium dahliae, as well as low levels of Thielaviopsis basicola. Five anastomosis groups (AG) of R. solani, namely AG2.1, AG2.2, AG3, AG4, and AG5, were detected, of which AG2.2 and AG4 were most prevalent. We believe this is the first report of occurrence for Ethiopia of A. euteiches, Ph. megasperma, T. basicola, and the five AGs for R. solani. There were very high incidence rates of the foliar pathogens Botrytis cinerea, B. fabae, Didymella pinodes, and Phoma pinodella and of the nematode Pratylenchus thornei, followed by P. neglectus and P. penetrans. The root rot severity and distribution varied significantly across regions, as well as with soil types, soil pH, and soil drainage. Subsequently, metabarcoding of the soil DNA was undertaken using three primer pairs targeting fungi (ITS2), Fusarium species (TEF1 α), and Oomycetes (ITS1Oo). The ITS2 and TEF1α primers emphasized F. oxysporum as the most abundant soilborne fungal pathogen and highlighted F. ananatum, F. brachygibbosum, F. brevicaudatum, F. clavum, F. flagelliforme, F. keratoplasticum, F. napiforme, F. nelsonii, F. neocosmosporiellum, F. torulosum, and F. vanettenii as first reports of occurrence for Ethiopia. The ITS1Oo primer confirmed Pythium spp. as the most prevalent of all Oomycetes. Full article

Entomopathogenic fungi (EPF) are substantial biocontrol agents reducing the populations of economically important pests in numerous crops. Recent findings indicate that their role in agroecosystems is more complex and extends to affecting plant physiology and growth. This study examined the effects of Beauveria bassiana and Isaria fumosorosea, as well as Salicylic acid (SA), on physiological parameters of grapevine (Vitis vinifera cv. Sauvignon Blanc). Additionally, the impact of SA on spore germination and pathogenicity of EPF against larvae of the European grapevine moth (Lobesia botrana) was tested. Foliar application of EPF was found to increase the electron transport rate (ETR) from PSII to PSI, indicating higher photosynthetic activity compared to control plants. EPF also elevated the transpiration rate (E) and stomatal conductance (gs). In contrast, SA treatments decreased E and gs, while the high dose (10 mM) exhibited reduced Fv/Fm value, accompanied by phytotoxic spots on leaves. Spore germination of both fungi was significantly reduced only by the SA concentration of 2 mM, while 0.5 and 1 mM did not affect germination. Combination EPF and SA treatments presented the highest larval mortality of L. botrana (87.5% at 28 °C and 77.5% at 24 °C for B. bassiana and I. fumosorosea, respectively). However, SA reduced larval mycosis in most cases. Overall, the results suggest that EPF and SA can be co-applied and included in vineyard integrated strategies to support grapevine health. Full article

Rice is a staple food for over half of the world’s population, and it is grown in over 100 countries. Rice blast disease can cause 10% to 30% crop loss, enough to feed 60 million people. Breeding for resistance can help farmers avoid costly fungicides. This study assessed the relationship between rice blast disease and zinc or anthocyanin content in biofortified rice. Susceptibility to foliar and panicle blast was assessed in a rice panel which differed on grain zinc content and pigmentation. A rice panel (n = 23) was challenged with inoculum of two isolates of Magnaporthe oryzae in a screenhouse-based assay. The zinc content with foliar blast severity was analyzed in the leaves and grain of a subset of non-inoculated rice plants. The effect of foliar zinc supplementation on seedlings was assessed by varying levels of zinc fertilizer solution on four blast susceptible cultivars at 14 days after planting (DAP), followed by inoculation with the blast pathogen at 21 DAP. Foliar blast severity was scored on a 0–9 scale at 7 days after inoculation. The rice panel was scored for anthocyanin content, and the data were correlated with foliar blast severity. The panel was grown in the field, and panicle blast, grain yield and yield-related agronomic traits were measured. Significant differences were observed in foliar blast severity among the rice genotypes, with IRBLK-KA and IR96248-16-2-3-3-B having mean scores greater than 4, as well as BASMATI 370 (a popular aromatic variety), while the rest of the genotypes were resistant. Supplementation with foliar zinc led to a significant decrease in susceptibility. A positive correlation was observed between foliar and panicle blast. The Zn in the leaves was negatively correlated with foliar blast severity, and had a marginally positive correlation with panicle blast. There was no relationship between foliar blast severity and anthocyanin content. Grain yield had a negative correlation with panicle blast, but no correlation was observed between Zn in the grain and grain yield. This study shows that Zn biofortification in the grain may not enhance resistance to foliar and panicle blast. Furthermore, the zinc-biofortified genotypes were not agronomically superior to the contemporary rice varieties. There is a need to apply genomic selection to combine promising alleles into adapted rice genetic backgrounds. Full article

The plant microbiome plays a crucial role in the health of the tea plant, while Bacillus thuringiensis (Bt) is widely utilized as a biological pesticide in tea gardens, promoting sustainable agricultural practices. However, the effects of Bt spraying on tea quality and the structure and function of the phyllosphere microbiome remain unclear. This study evaluated the effects of Bt spraying on tea quality, microbiome composition, diversity, and potential functions using tea leaf quality measurements and high-throughput sequencing of the 16S/ITS rDNA genes. Results showed that spraying Bt1 significantly increased the contents of free amino acids (by 15.27%), flavonoids (by 18.00%), soluble sugars (by 62.55%), and key compounds such as epicatechin gallate (by 10.50%), gallocatechin gallate (by 122.52%), and epigallocatechin gallate (by 61.29%), leading to improved leaf quality. Co-occurrence network analysis indicated that the community structure of both epiphytic and endophytic microbes became more complex after Bt treatment. The abundance of beneficial bacteria, such as Novosphingobium, Methylobacterium, and Sphingomonas, increased significantly, while pathogenic fungi like Aspergillus and Phyllosticta decreased. Functional prediction indicated enhanced amino acid metabolism, secondary metabolism, and carbohydrate metabolism, particularly the biosynthesis of flavonoids, which supports disease resistance and boosts secondary metabolite levels. Furthermore, Bt application reduced pathogenic fungi, enhancing the tea plant’s resistance to diseases. Overall, foliar spraying of Bt can positively alter the phyllosphere microbiome by enriching beneficial bacteria and improving metabolic functions, ultimately enhancing tea plant resistance and quality, and providing a scientific basis for sustainable pest management in tea cultivation. Full article

Foliar diseases caused by various fungi severely affect the yield and quality of banana crops. This study was conducted to clarify the biological characteristics of Bipolaris oryzae (teleomorph: Cochliobolus miyabeanus), a pathogen reported in 2023 as a new etiological agent of leaf spot in the banana variety ‘Pisang Mas’ (Musa acuminata, AA group) in Hainan Province, China, and to screen effective fungicides for its control. The results indicated that banana leaf extract agar (BLEA) and cornmeal agar (CMA) were the best media for the growth and sporulation of the pathogen, respectively. The pathogen grew best on a Czapek’s agar (CZA) medium with sucrose as a carbon source and yeast extract as a nitrogen source, while the optimal carbon and nitrogen sources for sporulation were lactose and beef extract, respectively. The pathogen could grow within a temperature range from 5 °C to 35 °C, and the optimal temperatures for growth and sporulation were 30 °C and 25 °C, respectively. Exposure to 50 °C for 10 min was lethal. Additionally, the pathogen could grow and sporulate within pH ranges of 4 to 10 and 4 to 9, respectively, and the optimal pH values for growth and sporulation were 5 and 8, respectively. The optimal photoperiods for growth and sporulation were 16 h light/8 h dark and 24 h light, respectively. Among the 12 tested fungicides, 500 g/L of iprodione SC showed the highest toxicity against B. oryzae, with an EC₅₀ value of 0.08 μg/mL, followed by 30% difenoconazole-azoxystrobin SC and 125 g/L of epoxiconazole SC, with EC₅₀ values of 0.13 μg·mL⁻¹ and 0.20 μg/mL, respectively. A fungicide containing 40% chlorothalonil SC had the poorest fungicidal activity, with an EC₅₀ value of 155.98 μg/mL. An artificial inoculation pot experiment showed that 125 g/L of epoxiconazole SC at 250 μg/mL, 500 g/L of iprodione SC at 1667 μg/mL, and 30% difenoconazole-azoxystrobin SC at 250 μg/mL provided a protective control efficacy of 100% against B. oryzae, while 125 g/L of epoxiconazole SC at 250 μg/mL and 500 g/L of iprodione SC at 1667 μg/mL provided a curative control efficacy of greater than 60%. This study clarified the optimal conditions for the mycelial growth and sporulation of B. oryzae isolated from banana and screened out fungicides with effective inhibitory activities. These results can provide guidance for field applications and the management of leaf spot caused by B. oryzae in banana. Full article

Streptomyces vinaceus strain SVFJ-07 is a biocontrol bacterium employed to control anthracnose disease caused by Colletotrichum gloeosporioides in Chinese orchids. This study investigated the mechanism of strain SVFJ-07-induced stomatal immunity-related closure in preventing the infection of anthracnose disease. After the foliar application of strain SVFJ-07, we analyzed the differential patterns of stomatal opening in Chinese orchids and measured the hormone levels of abscisic acid (ABA) and salicylic acid (SA). RNA sequencing (RNA-seq) was utilized to examine the differential expression of genes involved in SA and ABA signal transduction and disease resistance genes, which were induced by strain SVFJ-07. The results demonstrated that strain SVFJ-07 inhibited the infection of pathogens by inducing stomatal closure. Compared with the control group, the foliar application of strain SVFJ-07 significantly reduced stomatal length, width, and aperture. Furthermore, orchid plants treated with strain SVFJ-07 and infected with C. gloeosporioides exhibited elevated levels of endogenous ABA and SA, indicating that strain SVFJ-07 enhanced stomatal immunity and disease resistance in these plants. The transcriptome analysis revealed the upregulation of genes associated with stomatal immunity, particularly those involved in plant–pathogen interactions, peroxisome metabolism, plant hormone signaling, and mitogen-activated protein kinase (MAPK) signaling pathways. These findings confirmed that the induction of SVFJ-07 promoted stomatal closure to resist the infection of C. gloeosporioides and induced complex transcriptome-wide changes. Further investigation of the differentially expressed genes enhanced our understanding of the resistance mechanisms induced by S. vinaceus strain SVFJ-07. Full article

Anthracnose in beans is an important disease caused by Colletotrichum lindemuthianum, which affects crop productivity and infects the plant in all growth stages, affecting the quality of the pod and grains. The most viable strategy to control this disease is using bean cultivars; however, fungal variability is a limitation. Among the strategies proposed is using phosphite-based compounds, which can act as fungicides or priming stimulators. This study aimed to evaluate the antifungal activity of a phosphite-based solution (potassium phosphite (H₃PO₃), potassium hydroxide, and potassium citrate, in a formulation of phosphorus (P₂O₅) 28% and potassium (K₂O) 26%) on C. lindemuthianum under in vitro conditions. In addition, its effects as a defense inducer in Sutagao bean plants was determined by changes in disease severity and the expression of PR1, PR3, PR4, and POD (defense-related genes) in plants treated with the phosphite solution before infection with the fungus. The results showed that the potassium phosphite solution had a statistically significant antifungal effect on C. lindemuthianum, reducing mycelial growth by 42% and germination by 48%, at a dose of 5 mL L⁻¹. Foliar application of the phosphite-based solution showed a 17% reduction in anthracnose severity associated with high expression of the PR1, PR3, PR4, and POD defense genes, which increased in plants that were subsequently infected with the pathogen, demonstrating a priming effect. In conclusion, a potassium phosphite solution can be included in a management program to control bean anthracnose. Full article

Powdery mildew, a debilitating phytopathogen caused by biotrophic fungi within the order Erysiphales, endangers crop yields and global food security. Although traditional approaches have largely emphasized resistant cultivar development and chemical control, novel strategies are necessary to counter the advent of challenges, such as pathogen adaptation and climate change. This review fully discusses three principal areas of pathogen effector functions, e.g., the reactive oxygen species (ROS)-suppressive activity of CSEP087, and host susceptibility factors, like vesicle trafficking regulated by Mildew Locus O (MLO). It also briefly mentions the transcriptional regulation of resistance genes mediated by factors, like WRKY75 and NAC transcription factors, and post-transcriptional regulation via alternative splicing (As). In addition, this discussion discusses the intricate interactions among powdery mildew, host plants, and symbiotic microbiomes thereof, highlighting the mechanism through which powdery mildew infections disrupt the foliar microbiota balance. Lastly, we present a new biocontrol approach that entails synergistic microbial consortia, such as combinations of Bacillus and Trichoderma, to induce plant immunity while minimizing fungicide dependency. Through the study of combining knowledge of molecular pathogenesis with ecological resilience, this research offers useful insights towards climate-smart crop development and sustainable disease-management strategies in the context of microbiome engineering. Full article

This study investigates the uptake, translocation, and pathogen control efficacy of ethylicin in tomato plants using a combination of indoor root irrigation, spraying, and field root irrigation experiments. The results indicate that ethylicin shows dual-directional translocation in tomato plants. On the third day after foliar spraying, ethylicin was detected in the roots at a concentration of 2.93 mg/kg, indicating downward movement. On the third day after root irrigation, ethylicin was detected in the leaves at a concentration of 3.44 mg/kg, confirming upward movement. In the field experiments, ethylicin was absorbed and transported to the upper leaves within six hours of root irrigation at a concentration of 3.85 mg/kg for a single-agent ethylicin and 5.87 mg/kg for an ethylicin–oligosaccharin compound. These results indicate that oligosaccharins enhance the absorption of ethylicin. Ethylicin residue dissipated by the fifth day. No ethylicin was detected in the untreated controls. Root irrigation during the growing period showed an effective reduction of Fusarium spp. and Phytophthora spp. populations in the soil and control of soil-borne diseases. These findings provide theoretical support for the efficient application of ethylicin in the field. Full article

Selenium (Se) biofortification is a promising agronomic strategy to enhance the dietary intake of this essential micronutrient while simultaneously adding value to agricultural by-products like Brassica oleracea L. var. italica leaves. This study evaluated the effects of foliar Se biofortification on a fresh market broccoli cultivar (‘Belstar’) using selenite and selenate (1 and 2 mM). Growth performance, biochemical properties, nutraceutical quality, and phytohormone profiles of broccoli leaves were analyzed, highlighting their potential as functional by-products. Multivariate analysis revealed that 2 mM selenite application was the most effective treatment, significantly improving several parameters. Selenium biofortification with 2 mM selenite increased essential nutrient content, including Se, Ca, S, Fe, Mn, Mg, and Mo. It also enhanced the soluble protein content (+2.2-fold), phenolic compounds (+1.5-fold), and total antioxidant capacity (+1.4-fold) compared to control plants. In this sense, the nutraceutical quality of broccoli leaves was markedly improved, supporting their use as a source of bioactive ingredients. Additionally, to assess practical applications, water-extracted Se-enriched broccoli leaves demonstrated antifungal activity against the plant pathogen Fusarium solani, attributed to Se-induced alterations in phytohormone profiles. These findings suggest that Se-biofortified broccoli leaves can serve as a sustainable source of essential nutrients and bioactive compounds for the food industry. Furthermore, their antifungal properties position them as potential eco-friendly biopesticides to combat plant pathogenic fungi, thereby promoting sustainable agriculture. Full article

Pineapples are highly susceptible to “Wilt disease”, caused by the biotrophic insect Dysmicoccus brevipes that also transmits several Wilt-associated viruses (PMWaVs). Conventional farms manage mealybugs and Wilt disease using chemicals. However, many of these chemicals have been banned in Europe due to safety concerns, leading to a critical need for studies on pesticide-free control methods. During their evolution, plants have developed natural defences, such as systemic acquired resistance (SAR), against pathogens and pests. In this study, salicylic acid (10⁻³ M) was applied to MD2 and Queen Victoria pineapple plants as a foliar spray or soil drench, followed by mealybug infestation. This treatment enhanced defences, assessed through mealybug multiplication rates, and biochemical and molecular responses of tissue-cultured plantlets under controlled conditions. Phenylalanine ammonia-lyase activity (PAL) was measured as a potential SAR signalling enzymatic marker. Additionally, the expression levels of four genes were analyzed, which included AcPAL and AcICS2, both linked to salicylic acid synthesis; AcMYB-like, a transcription factor regulating salicylic acid biosynthesis; and AcCAT, which is involved in H₂O₂ level control in plants. SA elicitation reduced the mealybug multiplication rate by 70% on pineapples compared to untreated plants. In this study, the biochemical marker (PAL) and three molecular markers (AcPAL, AcICS2, and AcCAT) showed significant differences between primed and unprimed plants, indicating SAR induction and its role in the pineapple–mealybug interaction. In MD2 and Queen Victoria, PAL increased by 2.3 and 1.5, respectively, while AcPAL increased by 4 and more than 10. The other molecular markers, AcICS2, AcCAT, and AcMYB-like (a transcription factor), increased by 3, except for the last one in Queen Victoria. The reduction in mealybug populations with SAR is less effective than with pesticides, but it provides a valuable alternative on Réunion Island, where the only remaining insecticide will soon be banned. In addition, SAR priming offers a promising, eco-friendly strategy for managing mealybug populations and reducing Wilt disease in pesticide-free pineapple cropping systems. Full article

Tan spot (Pyrenophora tritici-repentis) and stripe rust (Puccinia striiformis f. sp. tritici) are major foliar diseases of wheat, causing significant yield losses globally. This study evaluated the efficacy of fungicide seed treatments in managing these diseases during early growth stages under greenhouse, growth chamber, and field conditions in the Northern Great Plains. Winter and spring wheat cultivars were treated with pyraclostrobin or combinations of thiamethoxam, difenoconazole, mefenoxam, fludioxonil, and sedaxane, among others. Greenhouse and growth chamber plants were inoculated with the respective pathogens, while field trials relied on natural inoculum. Fungicide treatments significantly reduced stripe rust severity (up to 36%) (p ≤ 0.05) and moderately reduced tan spot severity during early growth stages (15–20%). Treated plants demonstrated a 30–40% improvement in plant vigor, and a 25–50% increase in winter survival. Additionally, grain yield in treated plots increased by 25–50% (p ≤ 0.05), with test weight and protein content improving by 10% and 15%, respectively. These findings demonstrate the potential of fungicide seed treatments as an integrated pest (or pathogen) management (IPM) strategy to enhance early foliar disease control and wheat productivity. Full article

The role of pipecolic acid (Pip) in plant immune responses, particularly against bacterial wilt pathogens, is significant. This research aimed to understand the interaction between plant defense-responsive enzymes and Pip by analyzing methanolic extracts from different treatments of tolerant (GAT5) and susceptible (GT2) tomato cultivars. LC-MS analysis demonstrated that the foliar application of Pip significantly influenced tomato metabolites, especially in bacterial wilt-infected plants, with a more pronounced effect in tolerant varieties. Principal component analysis (PCA) revealed that Pip-treated plants of tolerant varieties exhibited better coordinated metabolome profiles than those of susceptible varieties. Notable variations were observed in the levels of specialized metabolites, such as salicylic acid (SA), N-hydroxy pipecolic acid (NHP), and Pip, which are essential for producing defense compounds. Molecular docking studies further explored Pip’s interactions with key plant enzymes involved in defense mechanisms and showed that Pip acts as an effective organic inducer of systemic acquired resistance (SAR). These findings highlight Pip’s potential as a natural agent for enhancing plant tolerance to pathogens, offering promising implications for agricultural practices and improving crop resilience against diseases. This study enhances our understanding of Pip’s role in plant defense and provides a foundation for developing Pip-based strategies for sustainable agriculture. Full article