Calcium enhanced the resistance against Phoma arachidicola by improving cell membrane stability and regulating reactive oxygen species metabolism in peanut.

BACKGROUND: Peanut (Arachis hypogaea), a vital oil and food crop globally, is susceptible to web blotch which is a significant foliar disease caused by Phoma arachidicola Marasas Pauer&Boerema leading to substantial yield losses in peanut production. Calcium treatment has been found to enhance plant resistance against pathogens. RESULTS: This study investigates the impact of exogenous calcium on peanut resistance to web blotch and explores its mechanisms. Greenhouse experiments revealed that exogenous calcium treatment effectively enhanced resistance to peanut web blotch. Specifically, amino acid calcium and sugar alcohol calcium solutions demonstrated the best induced resistance effects, achieving reduction rates of 61.54% and 60% in Baisha1016, and 53.94% and 50% in Luhua11, respectively. All exogenous calcium treatments reduced malondialdehyde (MDA) and relative electrical conductivity (REC) levels in peanut leaves, mitigating pathogen-induced cell membrane damage. Exogenous calcium supplementation led to elevated hydrogen peroxide (H2O2) content and superoxide anion (O2∙-) production in peanut leaves, facilitating the accumulation of reactive oxygen species (ROS) crucial for plant defense responses. Amino acid calcium and sugar alcohol calcium treatments significantly boosted activities of peroxidase (POD), superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) in peanut leaves. Activation of these antioxidant enzymes effectively scavenged excess ROS, maintaining ROS balance and mitigating cellular damage. CONCLUSIONS: In summary, exogenous calcium treatment triggered ROS production, which was subsequently eliminated by the activation of antioxidant enzymes, thereby reducing cell membrane damage and inducing defense responses against peanut web blotch.

Transcriptome Analysis Reveals Candidate Genes for Light Regulation of Elsinochrome Biosynthesis in Elsinoë arachidis.

Light regulation is critical in fungal growth, development, morphogenesis, secondary metabolism, and the biological clock. The fungus Elsinoë arachidis is known to produce the mycotoxin Elsinochrome (ESC), a key factor contributing to its pathogenicity, under light conditions. Although previous studies have predominantly focused on the light-induced production of ESC and its biosynthetic pathways, the detailed mechanisms underlying this process remain largely unexplored. This study explores the influence of light on ESC production and gene expression in E. arachidis. Under white light exposure for 28 days, the ESC yield was observed to reach 33.22 nmol/plug. Through transcriptome analysis, 5925 genes were identified as differentially expressed between dark and white light conditions, highlighting the significant impact of light on gene expression. Bioinformatics identified specific light-regulated genes, including eight photoreceptor genes, five global regulatory factors, and a cluster of 12 genes directly involved in the ESC biosynthesis, with expression trends confirmed by RT-qPCR. In conclusion, the study reveals the substantial alteration in gene expression associated with ESC biosynthesis under white light and identifies potential candidates for in-depth functional analysis. These findings advance understanding of ESC biosynthesis regulation and suggest new strategies for fungal pathogenicity control.

Molecular Identification and Analysis on Differential Pathogenicity of Cylindrocarpon Species Associated With Ginseng Root Rust Rot in Northeastern China.

Panax ginseng C. A. Meyer is one of the most important medicinal herbs in China. It is known for its high medicinal value and economic value. The ginseng root rust rot (RRR) has always been one of the important diseases troubling the ginseng industry. The yield reduction rate of RRR is ~30%. To understand why the Cylindrocarpon species bring about the ginseng RRR in Northeastern China, this study isolates 45 strains from samples collected in Liaoning, Jilin, and Heilongjiang provinces. The rDNA-internal transcribed spacer (ITS) sequence was analyzed to identify the pathogenic species. The morphological characteristics of colonies and conidia of each strain on potato dextrose agar (PDA) medium were observed, and the pathogenicity difference between different pathogenic species was analyzed by pricking method and determining the cell wall degrading enzyme activity. The BLAST alignment analysis shows that the homology of rDNA-ITS between 45 strains and Cylindrocarpon is more than 99%, among which 28 are identified as Cylindrocarpon destructans, three are identified as C. destructans var. destructans, and 14 are identified as Ilyonectria robusta. The colony diameters of all 45 isolated range from 4.21 ± 0.16a to 7.78 ± 0.25c cm after several days of incubation. Among all the species, I. robusta has the fastest growth rate, and C. destructans var. destructans has the slowest growth rate. Pathogenicity test results show that the pathogenicity of C. destructans var. destructans is the strongest, followed by C. destructans. I. robusta has relatively weak pathogenicity.

Identification and Characterization of Sclerotium delphinii Causing Southern Blight on Aconitum kusnezoffii in Northeast China.

Aconitum kusnezoffii is a perennial medicinal plant that belongs to the Ranunculaceae family and is distributed mainly in Northeast and North China. In July 2018, a typical southern blight disease of A. kusnezoffii was observed in commercial fields of Qingyuan County, Fushun City, Liaoning Province, China. The fungus mainly infected stem base and tuberous roots of the plant by wrapping the hyphae and absorbing nutrition, resulting in tuberous root wilted or whole plant death. Morphological characteristics of colony and sclerotia of three representative strains isolated from the diseased plants differed from those of Sclerotium rolfsii isolated from A. carmichaelii. Sclerotia were large (0.8 to 5.1 mm), reddish-brown, and irregular and had pitted surfaces, and the hyphae were white, compact, or fluffy, with a growth rate ranging from 8.0 to 10.1 mm/day. Phylogenetic analysis of the internal transcribed spacer and the large subunit sequences of Akln6, Akln9, and Akln15 showed that three strains isolated from A. kusnezoffii formed a unique and well-supported clade that groups with the reference isolates of S. delphinii. Based on phylogenetic analysis and cultural and morphological characteristics, the three isolates of A. kusnezoffii were identified as S. delphinii. The optimum temperature for mycelial growth of the three tested isolates was 30°C, and sclerotia formed and matured more easily at 20°C. Light promoted the growth of mycelial, whereas dark was beneficial to the formation and maturation of sclerotia. The pathogenicity of S. delphinii showed stronger than S. rolfsii at low temperature (20°C). This is the first report of S. delphinii causing southern blight on A. kusnezoffii in China, and this finding provides a basis for disease-accurate diagnosis and the development of effective management strategies.

Genomic analysis of Elsinoë arachidis reveals its potential pathogenic mechanism and the biosynthesis pathway of elsinochrome toxin.

Elsinochromes (ESCs) are virulence factors produced by Elsinoë arachidis which is the cause of peanut scab. However, the biosynthesis pathway of ESCs in E. arachidis has not been elucidated and the potential pathogenic mechanism of E. arachidis is poorly understood. In this study, we report a high-quality genome sequence of E. arachidis. The size of the E. arachidis genome is 33.18Mb, which is comparable to the Ascomycota genome (average 36.91 Mb), encoding 9174 predicted genes. The self-detoxification family including transporters and cytochrome P450 enzymes were analysis, candidate effectors and cell wall degrading enzymes were investigated as the pathogenicity genes by using PHI and CAZy databases. Additionally, the E. arachidis genome contains 24 secondary metabolism gene clusters, in which ESCB1 was identified as the core gene of ESC biosynthesis. Taken together, the genome sequence of E. arachidis provides a new route to explore its potential pathogenic mechanism and the biosynthesis pathway of ESCs.

Elsinochrome phytotoxin production and pathogenicity of Elsinoë arachidis isolates in China.

Peanut scab caused by Elsinoë arachidis is found throughout China's peanut-growing areas. Elsinochrome produced by E. arachidis is a perylenequinone photosensitive mycotoxin vital to the pathogenic process of the pathogen. In this study, the complex mechanism underlying the regulation of elsinochrome biosynthesis by E. arachidis was investigated based on various nutritional and environmental factors. The initiation of elsinochrome biosynthesis depends on light. E. arachidis produced substantially more quantities of elsinochrome when grown on a semi-synthetic medium (PDA) than when grown on synthetic media with defined ingredients in the presence of light. Elsinochrome accumulation decreased when adjusted with either citrate or phosphate buffers and changing pH suppressed the radical growth. At temperatures ranging from 10°C to 25°C, the production of elsinochrome increased, peaking at 28°C, and it decreased slightly at 30°C. 63 field-collected isolates from China were assessed for the level of elsinochrome production, and pathogenicity analysis was conducted by selecting 12 strains from each 3 of the 4 groups with different levels of elsinochrome production. A direct correlation was observed between elsinochrome production and pathogenicity among the isolates. The results showed elsinochrome biosynthesis to be controlled by E. arachidis and showed elsinochrome to be a vital virulence factor of E. arachidis, required for disease severity.

Effects of phenolic acids from ginseng rhizosphere on soil fungi structure, richness and diversity in consecutive monoculturing of ginseng.

Ginseng yield and quality are seriously compromised by consecutive monoculturing in northeastern China. The imbalance of soil fungi communities and autotoxicity of ginseng are the major factors in consecutive monoculturing ginseng crops. Soil fungal communities were identified using Illumina MiSeq sequencing, applied to soils that consecutively cultured ginseng (CCG) for six years and new forest soil (NFS), or receiving application of phenolic acids (PAs). The CCG field received five treatments with five different phenolic acids, including gallic acid (GA), salicylic acid (SA), 3-phenylpropionic acid (3-PA), benzoic acid (BA) and cinnamic acid (CA), which were detected from ginseng rhizosphere in consecutive cropping soil. Fungal richness, fungi diversity, community composition, relative taxon abundances, root rot disease, and growth rate were compared among the different treatments. 579 fungal operational taxonomic units at 97% ITS sequence identity were found among 201,617 sequence reads derived from 18 separate soil samples. Members of the phylum Ascomycota dominated the soil fungal communities, and putative pathogens, such as Fusarium, Gibberella and Nectriaceae_unclassified which may include the abundant sexual morph of Cylindrocarpon destructans, showed higher relative abundances in the CCG fields. Compared to the CCG and NFS fields, PAs (except CA) enhanced the fungi richness and decreased fungi diversity. Cluster analysis indicated that the PAs (except CA) changed the fungi structure in a uniform way. PAs stimulate root rot disease and enhance disease severity, restricting plant growth. The results suggest that the PAs (except CA) may enhance the fungi richness, decrease the fungi diversity and changed the fungi structure to increase fungal pathogen loads, which could explain the declined yield and quality of ginseng in consecutively monocultured ginseng crops.

Formation of sclerotia in Sclerotinia ginseng and composition of the sclerotial exudate.

BACKGROUND: Sclerotinia ginseng is a major devastating soil-borne pathogen of ginseng that can cause irreparable damage and large economic losses. This pathogen produces sclerotia, which are among the most persistent resting structures produced by filamentous fungi. The production of an exudate is a common feature of sclerotial development. METHODS: S. ginseng was cultured on 10 different media and the following parameters were measured: mycelial growth rate (mm/day), initial formation time of exudate droplets, total quantity of exudate, number of sclerotia per dish, and sclerotial fresh/dry weight. The composition of the sclerotial exudate was analyzed using four methods (high performance liquid chromatography, gas chromatography-mass spectrometry, flame atomic absorption spectrometry, and Nessler's reagent spectrophotometry). RESULTS: We found that PDA was the optimal medium for exudate production, while SDA medium resulted in the highest mycelial growth rate. The earliest emergence of exudate droplets from sclerotia was on OA-YE and V8 media. The largest amount of sclerotia and the smallest sclerotia were produced on V8 medium. The maximum and minimum dry/fresh weight were obtained on MEA medium and V8 medium, respectively. The exudate contained organic acids (oxalic acid, gallic acid, ferulic acid, vanillic acid, caffeic acid, and tannic acid), carbohydrates (inositol, glucose, and trehalose), various ions (potassium, sodium, and magnesium), and ammonia. DISCUSSION: The functions of the identified compounds are discussed within the context of pathogenicity, sclerotial development, and antimicrobial activity. Our findings provide information about the production of sclerotia and the composition of sclerotial exudate that may be useful to develop strategies to control this disease.

[Influence of exogenous ginsenosides on new forest soil microbial communities].

Ginsenosides are the main active ingredient and allelochemicals of Panax ginseng, and they play an important role in ginseng growth and in ecological adaptation. To study the influence of ginsenosides on soil microbial communities, the method of given exogenous total ginsenosides of different concentrations were used to study the influence of ginsenosides on new forest soil microbial community, evaluate the change of metabolic activity of microbial community and investigate the ecological effect of ginsenosides on soil microbial community. Results showed that, exogenous total ginsenosides promoted metabolic activity of microbial community in new forest soil at different concentrations compared with the control after 10 d and 40 d treatment. After 10 d,except for the Evenness index, all of the other indices indicated that the functional diversity of the soil microbial community in the new forest firstly increased then decreased with increase of the total ginsenosides concentration. The Substrate richness for 0.01 g•L⁻¹ soil treatment was significantly different from that of the control. After 20 d, 30 d and 40 d, except for the Evenness index, all of the other indices indicated that the functional diversity of the soil microbial community in the new forest increased with total ginsenosides. These results suggested that ginsenosids can change soil microbial community and microbial metabolic activity, which alter soil microbial ecology and accordingly affect the growth of ginseng with accumulation of ginsenosides in the soil.

Chemotactic response of Ginseng bacterial soft-rot to Ginseng root exudates.

Our purpose was to evaluate chemotactic response of Ginseng bacterial soft-rot to ginseng root exudates. The exudates of plant roots has a significant influence on the population changes of rhizosphere microorganisms and chemotaxis is an important way in which many pathogens sense the signals of host plants and invade the host plants. In this study, with the capillary method, we tested the chemotactic responses of Ginseng bacterial soft-rot for three ginseng roots exudates under four chemotactic parameters (concentration, temperature, pH and time). The results showed that the chemotatic response of the Ginseng bacterial soft-rot for the ginseng roots exudates at the water layer where pH = 7 and the concentration was 0.0125 mg/L reached its peak value under the circumstance that the exudates was cultivated for 60 min at 25 °C. The chemotatic ratios were respectively 124.89% and 89.44%. For the butanol extract layer and the petroleum ether faction at the concentration of 0.125 mg/L and the pH value at 7, the ginseng roots exudatess reached peak values at 25 °C and 30 °C and 60 min and 75 min respectively, and the chemotatic ratios were respectively 139.64% and101.87%, and 115.29% and 81.36%. The three ginseng roots exudates had positive effects for the chemotaxis of the Ginseng soft-rot bacteria, but the effect declined as the concentration increased.

Production of a transparent lavender flavour nanocapsule aqueous solution and pyrolysis characteristics of flavour nanocapsule.

Flavour plays an important role and has been widely used in many products. Usually, the components of flavour are volatile and the sensory perception can be changed as a result of volatilization, heating, oxidation and chemical interactions. Encapsulation can prevent the loss of volatile aromatic ingredients, provide protection and enhance the stability of the core materials. This work concentrated on production of a transparent lavender flavour nanocapsule aqueous solution. The results showed that a transparent lavender flavour microcapsule aqueous solution can be produced using hydroxypropyl-ß-cyclodextrin (HP-ß-CD) as wall material. The combination and interaction of flavour and wall materials were investigated by pyrolysis. Pyrolysis characteristics and kinetic parameters of the flavour nanocapsule were determined. During thermal degradation of blank HP-ß-CD and flavour-HP-ß-CD inclusion complex, three main stages can be distinguished. Due to the vaporization of lavender flavour encapsulated in HP-ß-CD, the thermogravimetric (TG) curve of blank HP-ß-CD shows a leveling-off from room temperature to 269 °C, while the TG curve of flavour-HP-ß-CD inclusion complex is downward sloping in this temperature range. The kinetic parameters are helpful in understanding the mechanism of molecular recognition between hosts and guests.

Study of production and pyrolysis characteristics of sweet orange flavor-ß-cyclodextrin inclusion complex.

Flavor plays an important role and has been widely used in foods. Encapsulation can prevent the loss of volatile aromatic ingredients, provide protection and enhance the stability of the flavor. Kinetic and thermodynamic parameters are helpful in understanding the mechanism of molecular recognition between hosts and guests. This work focused on the study of production of a sweet orange flavor-ß-cyclodextrin (CD) inclusion complex, and investigated the combination of flavor and ß-CD by thermogravimetric analysis. Pyrolysis characteristics, kinetic and thermodynamic parameters of the flavor-ß-CD inclusion complex were determined. The results showed that the flavor-ß-CD inclusion complexes can form large aggregates in water. During thermal degradation of blank ß-CD and flavor-ß-CD inclusion complex, three main stages can be distinguished. The thermogravimetric (TG) curve of blank ß-CD shows a leveling-off from room temperature to 250°C, while the TG curve of flavor-ß-CD inclusion complex is downward sloping in this temperature range.

Proteomic analysis of differentially expressed proteins induced by salicylic acid in suspension-cultured ginseng cells.

In this study, optimized 2-DE sample preparation methodologies were established for suspension-cultured ginseng cells. Three commonly used protein extraction methods (Trichloroacetic acid-acetone, urea/thiourea and phenol extraction method) were evaluated for proteomic analysis of suspension cultures of ginseng. A comparative analysis of suspension-cultured ginseng cells proteome induced by salicylic acid (SA) was reported. The results demonstrated that phenol extraction method was the best method based on protein extraction efficiency and the good quality of 2-DE patterns for suspension-cultured ginseng cells. Fifteen differentially expressed proteins induced by salicylic acid in suspension-cultured ginseng cells were identified by MALDI-TOF-MS. These identified proteins were involved in defense and stress response, energy metabolism, signal transduction/transcription, protein synthesis and metabolism, and photosynthesis. Chaperonin 60, related to defense responses, was more abundant in suspension-cultured ginseng cells after application of SA. Vacuolar ATPase subunit B was newly induced in SA treatment.

A review of the preparation and application of flavour and essential oils microcapsules based on complex coacervation technology.

This paper briefly introduces the preparation and application of flavour and essential oils microcapsules based on complex coacervation technology. The conventional encapsulating agents of oppositely charged proteins and polysaccharides that are used for microencapsulation of flavours and essential oils are reviewed along with the recent advances in complex coacervation methods. Proteins extracted from animal-derived products (gelatin, whey proteins, silk fibroin) and from vegetables (soy proteins, pea proteins), and polysaccharides such as gum Arabic, pectin, chitosan, agar, alginate, carrageenan and sodium carboxymethyl cellulose are described in depth. In recent decades, flavour and essential oils microcapsules have found numerous potential practical applications in food, textiles, agriculturals and pharmaceuticals. In this paper, the different coating materials and their application are discussed in detail. Consequently, the information obtained allows criteria to be established for selecting a method for the preparation of microcapsules according to their advantages, limitations and behaviours as carriers of flavours and essential oils.

The green adsorption of chitosan tripolyphosphate nanoparticles on cotton fiber surfaces.

Chitosan nanoparticles (chitosan NP) were effectively incorporated onto cotton fiber surfaces during a green adsorption without any cross-linking agents in this work. The interactions between cotton fibers and chitosan NP during the green adsorption were investigated by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), thermogravimetric-derivative thermogravimetry (TG-DTG) and scanning electron microscopy (SEM) in detail. The results indicated that the intermolecular hydrogen bond interactions exited between the hydroxyl groups of cotton fibers and the amino groups of chitosan NP, and progressively enhanced with the increase in chitosan NP mass concentrations. After chitosan NP adsorption, the acidity of fibers augmented and the crystallinity index of fibers declined owing to the increasing interactions. In addition, the hydrophobic interactions occurred between chitosan NP and crystalline cotton fibers, thereby resulting in the preferential adsorption onto the hydrophobic (200) crystallographic plane.

Pyrolysis characteristics of bean dregs and in situ visualization of pyrolysis transformation.

Biomass is an important renewable and sustainable source of energy. Waste products from biomass are considered as attractive feedstocks for the production of fuel. This work deals with the pyrolysis of bean dregs, a biomass waste from soybean processing industry. A technique has been developed to study bean dregs pyrolysis by in situ visualization of bean dregs transformation in a quartz capillary under a microscope using a charge-coupled device (CCD) camera monitoring system. The technique enables us to observe directly the processes and temperatures of bean dregs transformation during pyrolysis. In situ visualization of reaction revealed that how oily liquids are generated and expulsed concurrently from bean dregs during pyrolysis. Pyrolysis characteristics were investigated under a highly purified N(2) atmosphere using a thermogravimetric analyzer from room temperature to 800 °C at different heating rates of 10, 30 and 50 °C/min. The results showed that three stages appeared in this thermal degradation process. The initial decomposition temperature and the peak shifted towards higher temperature with an increase in heating rate. Kinetic parameters in terms of apparent activation energy and pre-exponential factor were determined.

[Effects of topical application of immunoglobulin yolk on mutans streptococci in dental plaque].

OBJECTIVE: To evaluate the inhibitory effects of topical application of specific immunoglobulin yolk antibodies (IgY) to mutans streptococci on composition of human dental plaque. METHODS: A total of 24 healthy adult volunteers were selected and randomly distributed into three experimental groups. After a supragingival scaling, the subjects were treated with an application of IgY containing spray (test group, n = 9), a 0.15% chlorhexidine(CH) spray(positive control group, n = 9) or a placebo phosphate buffered saline(PBS) spray without any active ingredients(negative control group, n = 6) three times daily for three weeks. Pooled plaque samples from the smooth surfaces of teeth were collected for microbiologic analysis before administration (baseline, day 0), during treatment(days 7, 14 and 21) and after withdrawal of the agents(days 28, 42 and 56) and plaque index were recorded. Microbial cultivation were performed by serially diluting the samples with PBS solution an cultivating the aliquots on mitis salivarius agar(MS) and MS supplemented with bacitracin (MSB) for oral streptococci and mutans streptococci respectively. The number of colony-forming unit (CFU) per plate was counted and the percentage of mutans streptococci per oral streptococci in dental plaque were determined. The effect of IgY on colonization of mutans streptococci were analyzed by an analysis of variance (ANOVA). RESULTS: The plaque indexes remained unchanged, but mutans streptococci in dental plaque was suppressed significantly following a short term(three weeks) application of IgY, and low level of mutans streptococci persisted for at least 5 weeks after withdrawal of IgY. CONCLUSION: The results suggest that the immunization with specific immunoglobulin yolk against mutans streptococci could be useful for long term suppression of mutans streptococci colonization in human dental plaque.

[The inhibitory effect of anti-streptococcus mutans immunoglobulin of yolk on glucan synthesis of Streptococcus mutans].

OBJECTIVES: To observe the inhibitory effect of anti-Streptococcus mutans Hen-egg-yolk (IgY) on glucan synthesis of Streptococcus mutans. METHODS: Determine the glucan with anthrone method after using the different titer of IgY on S.mutans and S.sobrinus. RESULTS: The inhibitory effect of antibody on S.mutans and S.sobrinus synthesis glucan had a similar tendency. The effect of inhibit glucan synthesis was influenced by the titer of antibody. High titer with high inhibition. Begin with the group of 1:16 titer, the group of 1:2 titer showed the highest inhibition (P<0.05). CONCLUSION: The antibody can reduce synthesis of glucan from S.mutans and S.sobrinus.