Activities Of Defense Enzymes Research Articles

Enhancement of antioxidant quality by Bacillus siamensis N-1 and the role of LcPOD4 in regulating peel browning and senescence of litchi fruit

Plant peroxidases (POD) are involved in various physiological and biochemical processes. Currently, there are relatively few studies on the role of POD in regulating the antioxidant capacity and senescence of postharvest litchi. In this study, we assessed the effects of Bacillus siamensis strain N-1 on the physiology and antioxidant quality of litchi fruit stored at 25 ℃, and characterized the molecular function of LcPOD4 gene in regulating the senescence of litchi fruit. The results showed that N-1 treatment significantly suppressed the increase in ethylene production, electrolyte leakage, and malondialdehyde (MDA) but did not inhibit the respiration rate of litchi during storage. Meanwhile, N-1-treated fruit maintained higher levels of phenolics, flavonoids, and total antioxidant capacity (T-AOC) and lower levels of superoxide anions (O2-.) and hydrogen peroxide (H2O2). In addition, N-1 treatment enhanced the activity of defense enzymes, including superoxide dismutase (SOD), peroxidase (POD), glutathione reductase (GR), and phenylalanine ammonia-lyase (PAL). The results of quantitative real-time PCR (qRT-PCR) showed that the expression of nine selected LcPOD genes was induced by N-1 treatment at later stages of litchi storage. LcPOD4 cloned from litchi fruit was located in the cell wall and membrane. Transient overexpression of the LcPOD4 gene in tomato and litchi fruits significantly enhanced POD activity and total phenolic and flavonoid contents while accelerating peel color change in the fruit. Collectively, our results indicate that LcPOD4 may contribute, at least partially, to the enhancement of antioxidant capacity in litchi fruit but does not retard peel browning and senescence.

Application of biochar and humic acid improves the physiological and biochemical processes of rice (Oryza sativa L.) in conferring plant tolerance to arsenic-induced oxidative stress.

Biochar (BC) and humic acid (HA) are well-documented in metal/metalloid detoxification, but their regulatory role in conferring plant oxidative stress under arsenic (As) stress is poorly understood. Therefore, we aimed at investigating the role of BC and HA (0.2 and 0.4gkg-1 soil) in the detoxification of As (0.25mM sodium arsenate) toxicity in rice (Oryza sativa L. cv. BRRI dhan75). Arsenic exhibited an increased lipid peroxidation, hydrogen peroxide, electrolyte leakage, and proline content which were 32, 30, 9, and 89% higher compared to control. In addition, the antioxidant defense system of rice consisting of non-enzyme antioxidants (18 and 43% decrease in ascorbate and glutathione content) and enzyme activities (23-50% reduction over control) was decreased as a result of As toxicity. The damaging effect of As was prominent in plant height, biomass acquisition, tiller number, and relative water content. Furthermore, chlorophyll and leaf area also exhibited a decreasing trend due to toxicity. Arsenic exposure also disrupted the glyoxalase system (23 and 33% decrease in glyoxalase I and glyoxalase II activities). However, the application of BC and HA recovered the reactive oxygen species-induced damages in plants, upregulated the effectiveness of the ascorbate-glutathione pool, and accelerated the activities of antioxidant defense and glyoxalase enzymes. These positive roles of BC and HA ultimately resulted in improved plant characteristics with better plant-water status and regulated proline content that conferred As stress tolerance in rice. So, it can be concluded that BC and HA effectively mitigated As-induced physiology and oxidative damage in rice plants. Therefore, BC and HA could be used as potential soil amendments in As-contaminated rice fields.

Rice resistance against Bipolaris oryzae infection is mediated by lower foliar potassium concentration

AbstractBrown spot, caused by Bipolaris oryzae, is a very important disease of rice. This study investigated the effect of potassium (K) on rice resistance to brown spot. The working hypothesis tested was that higher foliar K concentration could allow plants to respond more efficiently against fungal infection. Plants were grown in nutrient solution amended with three K rates (0.5, 1.0 and 2.5 mM) and noninoculated or inoculated with B. oryzae. The photosynthetic performance of plants, activities of defence and antioxidant enzymes and the concentrations of reactive oxygen species, phenolics and lignin were determined. Foliar K concentration was significantly higher by 38% and 91% for plants supplied with 1.0 and 2.5 mM K, respectively, compared to plants supplied with 0.5 mM K. Brown spot severity was significantly higher (≥20%) for plants supplied with 1.0 and 2.5 mM K than those supplied with 0.5 mM K (≤15%). Higher brown spot severity for plants supplied with 2.5 mM K resulted in changes in the photosynthetic apparatus, reduced chlorophyll a + b and carotenoids concentrations, and higher production of hydrogen peroxide and superoxide anion radical. In contrast, higher activities of defence and antioxidant enzymes and more production of phenolics for plants supplied with 0.5 mM K helped them to cope with B. oryzae infection more efficiently. In conclusion, rice resistance against brown spot was achieved by keeping a lower foliar K concentration linked to more active defence reactions, a robust antioxidative system and less damage to the photosynthetic apparatus.

The Agropyron mongolicum bHLH Gene AmbHLH148 Positively Involved in Transgenic Nicotiana benthamiana Adaptive Response to Drought Stress

While bHLH transcription factors have been linked to the regulation of various abiotic stressors, research on drought-related bHLH proteins and their molecular processes in Agropyron mongolicum has remained limited. In this study, a bHLH gene from A. mongolicum, designated as AmbHLH148, was successfully cloned and isolated. AmbHLH148 was exclusively localized within the nucleus. Additionally, qRT-PCR analysis demonstrated a significant upregulation of AmbHLH148 in response to drought stress. When transferred into tobacco (Nicotiana benthamiana), the heterologous expression of AmbHLH148 led to enhanced drought tolerance. Under drought stress conditions, AmbHLH148-OE transgenic tobacco plants exhibited increased activities of antioxidant defense enzymes, such as SOD (superoxide dismutase), POD (peroxidase), and CAT (catalase). These enzymes efficiently mitigated the accumulation of reactive oxygen species (ROS) compared to wild-type plants. Furthermore, AmbHLH148-OE transgenic tobacco showed elevated levels of PRO (proline) and reduced MDA (malondialdehyde) content, contributing to enhanced stability in the plant’s cell membrane system during drought stress. In summary, this study underscores that the overexpression of AmbHLH148 in transgenic tobacco acts as a positive regulator under drought stress by enhancing the plant’s antioxidant capacity. These findings shed light on the molecular mechanisms involved in bHLH transcription factors’ role in drought resistance, contributing to the discovery and utilization of drought-resistant genes in A. mongolicum for enhancing crop drought resistance.

Structural, defense enzyme activity and chemical composition changes in the xylem of Aquilaria sinensis during fungus induction

Agarwood is a dark resinous wood, of high quality and in a short period, can be formed after inoculation with the efficient fungus in Aquilaria sinensis. However, the action site and mechanism of the fungus inducing the agarwood formation remain unclear. In this work, the efficient fungal infection was used to induce agarwood formation on A. sinensis, and samples were collected according to inoculation time. Subsequently, the xylem structure, histochemistry, defense enzyme activities, and the accumulation and in-situ distribution of chemical composition were investigated. The transition layer (TL) was the critical layer for the continuous accumulation of agarwood, and began to appear in the injection of fungal inducers for 15 days (15D). The parenchyma cells of the xylem rays and interxylary phloem were the main action site of fungus in the formation and accumulation of agarwood. The sesquiterpenes and 2-(2-phenylethyl) chromones (PECs) were mainly accumulated in the agarwood layer (AL) and decay layer (DL), while their relative contents were highest in the injection of fungal inducers for 30 days and 180 days (30D and 180D), respectively. Among them, PECs appeared earlier than sesquiterpenes, and both were flindersia-type PECs. They were mainly concentrated in the cell corners and intercellular layer of the cell wall. In addition, Redundancy analysis (RDA) and Mantel test revealed that the different layer percentage (DLP), phenylalanine ammonia lyase (PAL), and starch grains (SG) were the drivers of PECs, and catalase (CAT) was the driver of sesquiterpenes. Therefore, this study will provide a theoretical foundation for revealing the mechanism of fungus-induced agarwood formation and inducing high-quality and high-yielding agarwood in the future.

Silicon application enhances wheat defence against Sitobion avenae F. by regulating plant physiological-biochemical responses

Sitobion avenae F. is a highly prevalent and devastating pest in wheat crops, leading to significant yield losses. Silicon (Si) has been widely recognized as an effective inducer of plant resistance against aphids. Nevertheless, the underlying mechanisms governing the physiological and biochemical responses of plants induced by Si defense against S. avenae F. remain incompletely understood. In this study, we conducted experiments by treating wheat leaves with varying concentrations of Tetraethyl orthosilicate (TEOS) spray under aphid infestation. We meticulously observed and recorded the life cycle of S. avenae F. and measured the content of plant hormones, secondary metabolites, and the activity of defense enzymes in wheat leaves. Furthermore, we utilized structural equation modeling to discern the causal correlation between aphid performance and the physiological-biochemical responses of wheat under TEOS sprays. Our findings revealed that a concentration of 3 mmol/L TEOS significantly shortened the net reproductive rate, intrinsic rate and finite rate of increase, and mean generation time of S. avenae F., while simultaneously prolonging the population doubling time. Additionally, the content of lignin, total phenolics, flavonoids, alkaloids, tannin, jasmonic acid (JA), and salicylic acid in wheat leaves exhibited a substantial increase. Furthermore, the activity of phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO), catalase, and lipoxygenase in wheat leaves was significantly enhanced. Our results suggest that TEOS spray reduced the survival and population growth of S. avenae F. while enhancing the defense response of wheat against aphids by activating the activity of PAL and PPO in wheat, and increasing the content of total phenolic and JA. This work provides valuable insights for the development of appropriate Si fertilizers for effective pest management and offers robust theoretical support for wheat aphid control through agricultural fertilization strategies.

Arsenic stress management through arsenite and arsenate-tolerant growth-promoting bacteria in rice.

Arsenic (As) contamination is a major problem affecting soil and groundwater in India, harming agricultural crops and human health. Plant growth-promoting rhizobacteria (PGPR) have emerged as promising agents for reducing As toxicity in plants. This study aimed to isolate and characterize As-tolerant PGPR from rice field soils with varying As levels in five districts of West Bengal, India. A total of 663 bacterial isolates were obtained from the different soil samples, and 10 bacterial strains were selected based on their arsenite (As-III) and arsenate (As-V) tolerant ability and multiple PGP traits, including phosphate solubilization, production of siderophore, indole acetic acid, biofilm formation, alginate, and exopolysaccharide. These isolates were identified by 16S rRNA gene sequencing analysis as Staphylococcus sp. (4), Niallia sp. (2), Priestia sp. (1), Bacillus sp. (1), Pseudomonas sp. (1), and Citricoccus sp. (1). Among the selected bacterial strains, Priestia flexa NBRI4As1 and Pseudomonas chengduensis NBRI12As1 demonstrated significant improvement in rice growth by alleviating arsenic stress under greenhouse conditions. Both strains were also able to modulate photosynthetic pigments, soluble sugar content, proline concentration, and defense enzyme activity. Reduction in As-V accumulation inoculated with NBRI4As1 was recorded highest by 53.02% and 31.48%, while As-III by NBRI12As1 38.84% and 35.98% in the roots and shoots of rice plants, respectively. Overall, this study can lead to developing efficient As-tolerant bacterial strains-based bioinoculant application packages for arsenic stress management in rice.

Screening and Regulatory Mechanisms of Inter-Root Soil Nematicidal Bacteria of Pinus massoniana

Pine Wilt Disease (PWD), caused by the pathogenic nematode Bursaphelenchus xylophilus, is a systemic infectious disease commonly referred to as the “cancer” of pine trees. This devastating disease has gained this analogy due to its ability to rapidly spread within pine populations, leading to substantial losses in forest resources. The primary objective of this study is to investigate the bioprotective potential and underlying mechanisms of action exhibited by rhizosphere microorganisms associated with Masson pine (Pinus massoniana) in the context of controlling the pine wilt nematode. In this experiment, using high-throughput sequencing, significant differences were observed in the rhizosphere soil microbial communities among healthy Masson pine, standing dead trees, and diseased Masson pine. Furthermore, it was found that these microbial communities exhibited distinct community structures at different levels. This study successfully isolated and screened three strains of highly effective nematophagous bacteria from the rhizosphere soil. The identified strains were Lysinibacillus capsici, Bacillus Paramycoides, and Delftia tsuruhatensis. After applying the bacterial suspensions and fermentation extracts of these three strains to the roots of two-year-old Masson pine seedlings, followed by inoculation with pine wilt nematodes after a four-day period, distinct defense responses were observed in the Masson pine. Notably, the activities of phenylalanine ammonia-lyase (PAL) and peroxidase (POD) were significantly increased, leading to a substantial reduction in the incidence of pine wilt disease. Based on the changes in defense enzyme activities, it can be concluded that the fermentation extract of the Lysinibacillus capsici strain exhibits effective nematocidal effects and induces resistance. The significant biological control efficacy and induction of host defense activity indicate the potential application value of this strain and its metabolites as a biocontrol agent for pine wilt disease.

Rice foliar-adapted Pantoea species: Promising microbial biostimulants enhancing rice resilience against foliar pathogens, Magnaporthe oryzae and Xanthomonas oryzae pv. oryzae

Foliar fungal blast and bacterial leaf blight have significant impacts on rice production, and their management through host resistance and agrochemicals has proven inadequate. To achieve their sustainable management, innovative approaches like leveraging the foliar microbiome, which collaborates with plants and competes against pathogens, are essential. In our study, we isolated three Pantoea strains (P. agglomerans Os-Ep-PPA-1b, P. vagans Os-Ep-PPA-3b, and P. deleyi Os-Ep-VPA-9a) from the rice phylloplane. These isolates exhibited antimicrobial action through their metabolome and volatilome, while also promoting rice growth. Our analysis, using Gas Chromatography-Mass Spectrometry (GC-MS), revealed the presence of various antimicrobial compounds such as esters and fatty acids produced by these Pantoea isolates. Inoculating rice seedlings with P. agglomerans and P. vagans led to increased root and shoot growth. Additionally, bacterized seedlings displayed enhanced immunocompetence, as evidenced by upregulated expressions of defense genes (OsEDS1, OsFLS2, OsPDF2.2, OsACO4, OsICS OsPR1a, OsNPR1.3, OsPAD4, OsCERK1.1), along with heightened activities of defense enzymes like Polyphenol Oxidase and Peroxidase. These plants also exhibited elevated levels of total phenols. In field trials, the Pantoea isolates contributed to improved plant growth, exemplified by increased flag-leaf length, panicle number, and grains per panicle, while simultaneously reducing the incidence of chaffy grains. Hypersensitivity assays performed on a model plant, tobacco, confirmed the non-pathogenic nature of these Pantoea isolates. In summary, our study underscores the potential of Pantoea bacteria in combatting rice foliar diseases. Coupled with their remarkable growth-promoting and biostimulant capabilities, these findings position Pantoea as promising agents for enhancing rice cultivation.

Eco-Friendly Cinnamic Acid Derivatives Containing Glycoside Scaffolds as Potential Antiviral Agents.

Natural products are a crucial source in the development of new eco-friendly antiviral agents to control plant viral diseases. In our previous studies, some ferulic acid derivatives with good antiviral activity were obtained as an immune activator. To continue the discovery of eco-friendly antiviral agents, different monosaccharides were introduced into cinnamic acid skeletons by an activity-based strategy to obtain a series of cinnamic acid derivatives containing glycoside scaffolds, and their antiviral activities against tobacco mosaic virus (TMV) and tomato spotted wilt virus (TSWV) were evaluated. Among them, compound 8d showed the greatest protective activities against TMV and TSWV, with the EC50 values of 128.5 and 236.8 μg mL-1, respectively, which were superior to those of ningnanmycin (238.5 and 315.7 μg mL-1, respectively). Moreover, compound 8d could significantly improve the defense enzyme activities of peroxidase, chitinase, and β-1,3-glucanase. Proteomic and transcriptome analyses indicated that compound 8d regulated gene transcription and protein expression levels involved in the defense response to resist virus infection. The present study revealed that compound 8d is a potential lead candidate for the development of novel, eco-friendly, and natural-product-based antiviral agents.

Feeding-induced plant metabolite responses to a phoretic gall mite, its carrier psyllid and both, after detachment.

Phoresy is one of the most distinctive relationships between mites and insects, and the off-host interaction between phoretic mites and their carriers is the most critical factor sustaining the phoretic association. As phoretic associations commonly occur in temporary habitats, little is known about off-host interactions between phoronts and carriers. However, an off-host interaction has been reported, in which the plant-mediated competition between a phoretic gall mite, Aceria pallida, and its psyllid vector, Bactericera gobica, after detachment decreases leaf abscission caused by B. gobica and then directly facilitates their phoretic association. In this obligate phoresy, A. pallida seasonally attaches to B. gobica for overwinter survival and they share the same host plant, Lycium barbarum, during the growing season. It is unknown how the host plant responds to these two herbivores and what plant metabolites are involved in their interspecific interaction. Here, effects of A. pallida and B. gobica on the host plant's transcriptome and metabolome, and on enzymes involved in plant defence, at various infestation stages were studied by inoculating A. pallida and B. gobica either separately or simultaneously on leaves of L. barbarum. Our results showed that (a) A. pallida significantly promoted primary and secondary metabolite accumulation, (b) B. gobica markedly inhibited primary and secondary metabolite accumulation and had little influence on defence enzyme activity, and (c) under simultaneous A. pallida and B. gobica infestation, an intermediate response was predicted. These findings indicate that A. pallida and B. gobica have different effects on host plants, A. pallida inhibits B. gobica mainly by increasing the secondary metabolism of L. barbarum, whereas B. gobica inhibits A. pallida mainly by decreasing the primary metabolism of L. barbarum. In conjunction with our previous research, we speculate that this trade-off in host plant metabolite response between A. pallida and B. gobica after detachment promotes a stable phoretic association.

Induction of defense-related enzymes and enhanced disease resistance in rice against Sarocladium oryzae by Bacillus cereus RBS-57

Bacillus species have been identified as effective bioagents and plant growth boosters in rice. Currently, there is limited research on the effectiveness of Bacillus strains in managing the sheath rot disease of rice caused by Sarocladium oryzae, a significant threat to rice-cultivating areas in India. The aim of this study was to evaluate the efficacy of Bacillus spp. to control the sheath rot disease and promote growth in rice plants. We investigated the in vitro antagonistic activity and growth-promoting potential of eighty-four Bacillus spp. against S. oryzae. Ten efficient strains were carefully selected and analyzed at the molecular level based on their capacity for antagonism and growth promotion. A PCR study of the potential strains has revealed the presence of lipopeptide genes that produce bacilysin, bacillomycin, iturin, surfactin, subtilin, subtilosin and fengycin. Among the strains, RBS-57 had the highest mycelial growth inhibition (74.44 %) of the pathogen as well as the highest number of antibiotic genes (6). The efficacy of talc and liquid formulations of Bacillus strains BS-5, RBS-57, and RBS-3 was further tested against sheath rot disease. Results indicated that a combined application of seed treatment + seedling dip + foliar spray of RBS-57 liquid formulation under pot culture conditions, showed a considerable reduction in the incidence of sheath rot disease, followed by BS-5 and RBS-3. Similarly, a significant increase in the plant growth attributes and yield was observed with RBS-57, when compared to the other treatments. Enzymatic activities such as PO, PPO, PAL, CAT and SOD were induced in the rice sheath by B. cereus (RBS-57) treatment. Real-time expression analysis was performed to validate the fold changes in defense enzymes and reactive oxygen species. The effectiveness of RBS-57 liquid formulation in reducing disease incidence was demonstrated when applied as a combination of seed treatment @ 10 ml/l + seedling dip @ 10 ml/l + foliar spray @ 10 ml/l. Moreover, higher defense enzyme activities, maximum plant growth promotion and higher yield were reported with RBS-57 treatment. This study has the potential to be exploited to manage sheath rot disease in an eco-friendly and sustainable manner.

Synthesis and characterization of chitosan-zinc-salicylic acid nanoparticles: A plant biostimulant

The vastly expanding global population raised the demand for profuse food grain production. For food security in India, high yield and nutritional quality of grain crops, both are essential. Zinc is a crucial micronutrient generally deficient in food grains grown in India, reflecting their deteriorating nutritional quality. To address these issues, in the present study, a novel tri-component nanoparticle of chitosan‑zinc-salicylic acid (CS-Zn-SA NPs) has been synthesized by ionotropic gelation method. The average size of synthesized CS-Zn-SA NPs was recorded 13.5 nm by dynamic light scattering (DLS) spectroscopy. The presence of chitosan, zinc and salicylic acid and crosslinking among these components in synthesized nanoparticles has been demonstrated by Fourier transforms infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). Further, synthesized CS-Zn-SA NPs at various concentrations (50–200 ppm) were evaluated for seed germination via seed priming, yield, grain zinc content and defence enzyme activity through the foliar application. CS-Zn-SA NPs revealed significant seed germination activities, 19.8 % higher grain yield, 45.5 % increased grain zinc content and manyfold defence enzyme activities than the control. The obtained results exposed the potential of CS-Zn-SA NPs as a stimulant for effective seedling development, higher yield, a virtuous micronutrient fortifying agent and defence enzyme promoter.

Preservation effect of Lactobacillus plantarum O2 fermentation supernatant on postharvest pepper and its induced resistance to Phytophthora capsici

Research of lactic acid bacteria and its metabolites on biological preservatives becomes a hot topic. Lactobacillus plantarum O2, with good inhibition on Phytophthora capsici (P. capsici), was isolated from the pickle. In this study, the effects of L. plantarum O2 fermentation supernatant (FS) on pepper postharvest preservation and its induced resistance to P. capsici were studied. Results showed that weight loss rate, rot index, respiration rate, relative electrical conductivity, loss of chlorophyll content and VC of pepper in FS treatment group were decreased by 18 %, 64 %, 15 %, 26 %, 33 % and 20 % compared with blank control (BC) after 20 d storage. L* and b*-value of pepper in FS group were lower than those in the BC group. In addition, the damage-induced resistance test found that the infection rate in the FS group was reduced by 39 %, compared with CK2 after 12 d storage. Moreover, phenylalanine ammonia-lyase activity, peroxidase activity, polyphenol oxidase activity, proline content, total phenol content and flavonoid content increased by 14 %, 9 %, 30 %, 8 %, 8 % and 9 %, respectively, while malondialdehyde content decreased by 13 %. These results indicated that FS treatment showed good fresh-keeping effects on postharvest pepper. It could enhance the tolerance of pepper under stress by improving defensive enzyme activities, slowing down the damage caused by P. capsici, and inducing pepper resistance to P. capsici. Therefore, FS can be used as a microbial source bio-preservative for postharvest pepper.

Do Vermicompost Applications Improve Growth Performance, Pharmaceutically Important Alkaloids, Phenolic Content, Free Radical Scavenging Potency and Defense Enzyme Activities in Summer Snowflake (Leucojum aestivum L.)?

Leucojum aestivum L. contains galanthamine and lycorine, which are two pharmaceutically valuable alkaloids. Vermicompost (VC), an organic waste product created by earthworms enhances soil quality and can improve the medicinal quality of the plant that is crucial to the pharmaceutical industry. The aim of this study was to determine the effects of four different VC concentrations (5 %, 10 %, 25 %, and 50 %) on L. aestivum growth parameters, alkaloid levels (galanthamine and lycorine), total phenol-flavonoid content, free radical scavenging potential, and defense enzyme activities (SOD and CAT) compared to control (no VC). The width, length, and fresh weight of the leaves were improved by 10 % VC treatment. The highest total phenolic content was found in the bulbs and leaves treated with 50 % VC. HPLC-DAD analysis of alkaloids showed that 10 % and 50 % VC treatments contained the most galanthamine in the bulb and leaf extracts, respectively. The application of 25 % VC was the most efficient in terms of lycorine content in both extracts. CAT activity was elevated at 10 %, 25 %, and 50 % VC. Based on the growth performance and galanthamine content of the bulbs and leaves, it can be concluded that a 10 % VC application was the most effective in the cultivation of L. aestivum.

Effect of Boric Acid on Oxidative Damage in Immunocompetent Organs under Conditions of Potassium Bichromate and Gamma Radiation Exposure

The immune system supports antigenic homeostasis in the body and regulates the processes of proliferation and differentiation of cellular components in hemo- and immunopoiesis. Chromium compounds and ionizing radiation lead to the formation of highly reactive free radicals. Sublethal dose of gamma-irradiation is characterized by a 56% decrease in thymus cellularity and a 22% decrease in lymph nodes against the background of a 44% increase in the number of lymphoid cells in the spleen. Under the combined effect of hexavalent chromium and gamma-radiation, a decrease in the number of lymphoid cells is observed. In thymus the cellularity decreases by 70%, in spleen - by 40%, in lymph nodes - by 42% in comparison with control data. Under the influence of boric acid the number of lymphoid cells in thymus significantly increases by 47%, in lymph nodes - by 14% (p<0.05) compared to the data of irradiated animals. Boric acid administration weakens the development of oxidative stress, lipid peroxidation decreases, and the activity of antioxidant defense enzymes in immunocompetent cells is increased.

Synergistic benefits of Funneliformis mosseae and Bacillus paramycoides: Enhancing soil health and soybean tolerance to root rot disease

To explore the response of soil metabolite composition to soybean disease, the effect of the combined inoculation of arbuscular mycorrhizal fungi (AMF) and plant growth-promoting bacteria on soybean root rot caused by Fusarium oxysporum was studied. A factorial completely randomized design with three factors (AMF, Bacillus. paramycoides, and rot disease stress) was conducted, and eight treatments, including normal groups and stress groups, were performed using pot experiments. GC‒MS and enzymatic assays were used to evaluate the soil factors and soybean growth indicators. The results showed that there were significant differences in the composition of metabolites among the different treatment groups, and 23 metabolites were significantly related to soybean biomass. The combined inoculation of Funneliformis mosseae and Bacillus paramycoides resulted in a significant reduction in harmful soil metabolites associated with root rot disease, such as ethylbenzene and styrene. This reduction in metabolites contributed to improving soil health, as evidenced by enhanced soybean defence enzyme activities and microbial activity, and β-1,3-glucanase, chitinase and phenylalanine ammonia-lyase activities were improved to alleviate plant rhizosphere stress. Furthermore, soybean plants inoculated with the synergistic treatments exhibited reduced root rot disease severity and improved growth indicators compared to control plants. Plant height, root dry weight (RDW), and shoot and root fresh weight (SRFW) were improved by 4.18–53.79%, and the AM fungal colonization rate was also improved under stress. The synergistic application of Funneliformis mosseae and Bacillus paramycoides can effectively enhance soil health by inhibiting the production of harmful soil metabolites and improving soybean tolerance to root rot disease. This approach holds promise for the sustainable management of soil-borne diseases in soybean cultivation.

Rosavin thwarts amyloid-β-induced macromolecular damages and neurotoxicity, exhibiting anti-Alzheimer's disease activity in Wister rat model.

Lately, interest surrounding the utilization of plant-derived compounds as a viable beneficial approach for treating Alzheimer's disease (AD) has significantly increased. This study aimed to assess the defensive properties of rosavin against Alzheimer's disease induced by amyloid-β, utilizing experimental models. We found that rosavin exhibited anti-aggregation and disaggregation properties, suggesting its potential to prevent the gathering of Aβ-aggregates. In vitro experiments revealed that rosavin effectively mitigated the neurotoxicity induced by Aβ in Neuro-2a cells, showcasing its protective potential. Rosavin significantly improved the Aβ-induced cognitive deficits in Wistar rats, particularly in spatial memory. Which the pathophysiology of AD includes oxidative damage, which negatively impacts biological macromolecules. Triggers the apoptotic process, causing macromolecular destruction. Interestingly, rosavin attenuated Aβ-induced macromolecular damages, thereby preserving neuronal integrity. Furthermore, the activation of antioxidative defense enzymes by rosavin inhibited oxidative damage. The positive outcomes associated with rosavin were primarily attributed to its capacity to enhance acetylcholine-mediated effects. Finally, rosavin has the potential to alleviate Aβ-induced neurotoxicity and macromolecular damages, ultimately resulting in enhanced memorial and reasoning function in Wistar rats, offering promising prospects for the treatment of AD.

Comparative transcriptome analysis of the resistance mechanism of Hemerocallis citrina Baroni to Puccinia hemerocallidis infection

ABSTRACT Hemerocallis citrina Baroni (daylily) is an important cash crop in many regions of China. Daylily rust caused by Puccinia hemerocallidis (Ph) is a major disease in H. citrina. Rust infection on the leaves of two resistant and susceptible varieties of H. citrina was examined. Transcriptome sequencing and defense enzyme activity were used to analyze the differential expression of related genes after 0, 72, 144, 192, and 288 h, to reveal the response mechanism of H. citrina to rust infection and screen-related resistance genes. The results suggested that 72 h after Ph infection was the key time point for determining differences between resistant and susceptible varieties. DEGs were significantly enriched in phenylpropanoid biosynthesis, plant–pathogen interaction, plant hormone signal transduction, and the MAPK signaling pathway. TFs WRKY33 and CYP98A are key genes closely related to the disease-resistance response of H. citrina. This study is the first large-scale transcriptomic analysis of H. citrina.

Cinnamaldehyde Inhibits Postharvest Gray Mold on Pepper Fruits via Inhibiting Fungal Growth and Triggering Fruit Defense.

Gray mold infected with Botrytis cinerea frequently appears on fruits and vegetables throughout the supply chain after harvest, leading to economic losses. Biological control of postharvest disease with phytochemicals is a promising approach. CA (cinnamaldehyde) is a natural phytochemical with medicinal and antimicrobial activity. This study evaluated the effect of CA in controlling B. cinerea on fresh pepper fruit. CA inhibited B. cinerea growth in vitro significantly in a dose- (0.1-0.8 mM) and time-dependent (6-48 h) manner, with an EC50 (median effective concentration) of 0.5 mM. CA induced the collapse and breakdown of the mycelia. CA induced lipid peroxidation resulting from ROS (reactive oxygen species) accumulation in mycelia, further leading to cell leakage, evidenced by increased conductivity in mycelia. CA induced mycelial glycerol accumulation, resulting in osmotic stress possibly. CA inhibited sporulation and spore germination resulting from ROS accumulation and cell death observed in spores. Spraying CA at 0.5 mM induced a defense response in fresh pepper fruits, such as the accumulation of defense metabolites (flavonoid and total phenols) and an increase in the activity of defense enzymes (PAL, phenylalanine ammonia lyase; PPO, polyphenol oxidase; POD, peroxidase). As CA is a type of environmentally friendly compound, this study provides significant data on the activity of CA in the biocontrol of postharvest gray mold in peppers.