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Volatile organic compounds (VOCs) of antagonistic yeasts are considered as environmental safe fumigants to promote the resistance and quality of strawberry (Fragaria ananassa). By GC‐MS assays, VOCs of Hanseniaspora uvarum (H. uvarum) fumigated strawberry fruit showed increased contents of methyl caproate (5.8%), methyl octanoate (5.1%), and methyl caprylate (10.9%) in postharvest cold storage. Possible mechanisms of H. uvarum VOCs involved in regulations of the defense‐related enzymes and substances in strawberry were investigated during postharvest storage in low temperature and high humidity (2 ± 1°C, RH 90%–95%). Defense‐related enzymes assays indicated H. uvarum VOCs stimulated the accumulation of CAT, SOD, POD, APX, PPO, and PAL and inhibited biosynthesis of MDA in strawberry fruit under storage condition. Moreover, the expression levels of related key enzyme genes, such as CAT, SOD, APX42, PPO, and PAL6, were consistently increased in strawberry fruit after H. uvarum VOCs fumigation. Hanseniaspora uvarum volatile organic compounds (VOCs) increase specific esters in strawberry volatile emissions during postharvest storage. It also enhances the activity of defense‐related enzymes and inhibits the accumulation of MDA content and the production rate of superoxide anion. This study also showed that these VOCs maintain the strawberry quality via inducing the expression of defense‐related enzyme genes.

Inonotus hispidus has various health-promoting activities, such as anticancer effects and immune-stimulating activity. The commercialization of valuable plant triterpenoids faces major challenges, including low abundance in natural hosts and costly downstream purification procedures. In this work, orthogonal design was used to compound methyl jasmonate (MeJA), salicylic acid (SA), oleic acid, and Cu2+, and the effects of combinations on the total triterpenes biosynthesized were studied. The optimal combination was screened out and its effect on the activity of PAL, CAT, and SOD was studied. The optimal concentration of oleic acid was 2% when MeJA was 100 mol/L, and the total triterpenoid content and mycelia production were 3.918 g and 85.17 mg/g, respectively. MeJA treatment induced oxidative stress, and at the same time increased the activity of related defense enzymes. Oleic acid is thought to regulate cell permeability by recombining cell membranes. It promotes the material exchange process between cells and the environment without affecting cell growth. When oleic acid was used in combination with MeJA, a synergistic effect on triterpene production was observed. In conclusion, our findings provide a strategy for triterpenoid enrichment of I. hispidus.

Drought is one of the most severe environmental stressors that place major constraints on the growth of soybeans ( Glycine max L.). Graphene oxide (GO) is a nanomaterial that can promote plant growth without toxic effects. In this study, the physiological and molecular responses to drought stress with GO treatment were examined. We discovered that the relative water content (RWC) of stems and leaves treated with GO was 127 and 128% higher than that of the WT plants, respectively. The root parameters in GO-treated soybeans were increased by 33, 38, 34, and 35% than WT plants in total root length, root surface area, root diameter, and root volume, respectively. The activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX) were also increased by 29, 57, 28, and 66%, respectively. However, the relative conductivity (REC), malondialdehyde (MDA), and hydrogen peroxide (H 2 O 2 ) accumulation were remarkably decreased. Furthermore, the content of drought-related hormones JA, SA, and ABA in GO-treated soybeans increased by 32, 34, and 67% than WT plants, respectively. At the molecular level, the effects of GO treatment were manifested by relatively higher expression of four drought-related genes: GmP5CS , GmGOLS , GmDREB1 , and GmNCED1 . Taken together, our findings revealed that GO could directly increase plant defense enzymes, hormone content, and the expression of drought-related genes, thereby improving the soybean’s ability to resist drought. These findings could provide new opportunities for improving drought tolerance in soybeans through effective soil water retention agents.

Salinity has become a crucial environmental factor seriously restricting maize ( Zea mays L.) growth, development and productivity. However, how plants respond to salt stress is still poorly understood. In this study, we report that a maize brassinosteroid-signaling kinase gene ZmBSK1 plays a significant role in salt stress response. Expression pattern analysis revealed that the transcript level of ZmBSK1 was upregulated by NaCl treatment both in maize leaves, roots, and stems. Phenotypic and physiological analysis showed that overexpression of ZmBSK1 in maize improved salt tolerance by reducing the malondialdehyde (MDA) content, the percentage of electrolyte leakage, O 2 − and H 2 O 2 accumulation under salt stress, relying on the increases of antioxidant defense enzyme activities and proline content. qRT-PCR analysis showed that overexpression of ZmBSK1 also positively modulated the expression levels of reactive oxygen species (ROS)-scavenging and proline biosynthesis-related genes under salt stress. Moreover, immunoprecipitation-mass spectrometry (IP-MS) assay and firefly luciferase complementation imaging (LCI) assay showed that ZmBSK1 could associate with heat shock protein ZmHSP8 and 14-3-3-like protein ZmGF14-6, and their gene expression levels could be significantly induced by NaCl treatment in different maize tissues. Our findings unravel the new function of ZmBSK1 in salt stress response, which provides the theoretical bases for the improvement of maize salt resistance.

The phytoelicitor and phytostimulatory properties of alkaline extracts of two tropical seaweeds, Sargassum vulgare C. Agardh and Acanthophora spicifera (M.Vahl) Børgesen, collected from the coasts of Trinidad were investigated in tomato and sweet pepper crops. Foliar applications of seaweed extracts (SWE), at 0.5% concentration, resulted in substantial reductions in disease severity by the pathogens, Xanthomonas campestris pv. vesicatoria and Alternaria solani under greenhouse and field conditions. The effects of SWE on disease suppression were significantly improved when integrated with a minimum dose of fungicide. SWE-treated plants also showed enhanced plant growth and yield parameters. Investigations into the modes of action for disease suppressive effects revealed that SWE-treated plants had sustainably augmented defense enzyme activities and phenolic levels. The activation of defense pathways was validated by confirming the upregulation of marker gene transcripts (PR-1a, PinII, and ETR-1) which are involved in defense signalling pathways. The SWE-treated plants also showed significant upregulation of genes involved in auxin (IAA), gibberellin (Ga2Ox), and cytokinin (IPT) biosynthesis. Multiple applications of SWE in crop plants have minimized the need for chemical fungicide sprays. The current study demonstrates the applicability of tropical SWE for use in vegetable plants for achieving environmental-friendly and sustainable crop production.

Oxidative stress plays a key role in many physiological and pathological conditions. The intracellular oxidative homeostasis is tightly regulated by the reactive oxygen species production and the intracellular defense mechanisms. Increased oxidative stress could alter lipid, DNA, and protein, resulting in cellular inflammation and programmed cell death. Evidences show that oxidative stress plays an important role in the progression of various cardiovascular diseases, such as atherosclerosis, heart failure, cardiac arrhythmia, and ischemia-reperfusion injury. There are a number of therapeutic options to treat oxidative stress-associated cardiovascular diseases. Well known antioxidants, such as nutritional supplements, as well as more novel antioxidants have been studied. In addition, novel therapeutic strategies using miRNA and nanomedicine are also being developed to treat various cardiovascular diseases. In this article, we provide a detailed description of oxidative stress. Then, we will introduce the relationship between oxidative stress and several cardiovascular diseases. Finally, we will focus on the clinical implications of oxidative stress in cardiovascular diseases.

Background Juglans regia L. is an important nut tree that has a wide range of distribution in temperate regions of the world. In some walnut orchards, walnut blight can become a problematic disease that affects the growth of walnut trees. To explore the correlation between biochemical response and walnut resistance, we inoculated four walnut cultivars with Xanthomonas arboricola pv. juglandis (Xaj). The walnut cultivars were, namely, ‘Xiangling’, ‘Xiluo 2’, ‘Yuanfeng’ and ‘Xifu 2’. Total phenol content (TPC) and total flavonoid content (TFC) were measured, whereby nine major phenolic compounds and several relevant enzymes were identified. Results The results showed that the most resistant and susceptible walnut varieties were ‘Xiluo 2’ and ‘Xifu 2’ respectively. The reaction of walnut to Xaj was characterized by the early accumulation of phenolic compounds in the infected site. After inoculation with Xaj, we found that the resistant variety ‘Xiluo 2’ show the significant differences with other varieties at different time points through the determination of related antioxidant enzymes such as catalase (CAT) and peroxidase (POD). Meanwhile, the phenylalanine ammonia lyase (PAL) of ‘Xiluo 2’ increased significantly at 8 day post infection (dpi) and made differences from the control samples, while other varieties changed little. And the polyphenol oxidase (PPO) was significantly higher than in the control at 16 dpi, maintaining the highest and the lowest activity in ‘Xiluo 2’ and ‘Xifu 2’ respectively. It was also found that the content of protocatechuic acid in all cultivars increased significantly at 4 dpi, and ‘Xiluo 2’ was significantly higher than that of the control. In the early stage of the disease, ferulic acid content increased significantly in ‘Xiluo 2’. Conclusion Our findings confirmed that the metabolism of phenolic compounds and related defense enzymes are of great significance in the response of walnut to Xaj.

Endophytic fungi can promote host plant growth, enhance antioxidant defense enzyme activity, and induce the biosynthesis and accumulation of secondarymetabolites. Therefore, using endophytic fungi to improve the quality and yield of medicinal plants or important crops is an effective means of regulation. Colletotrichum sp. AP12 has been reported to produce andrographolide compounds (ADCs). This study aimed to investigate the effects of AP12 and its elicitors on the growth, defense enzyme activity, accumulation, and transcription levels of key genes in Andrographis paniculata (Burm. f.) Nees ( A. paniculata ). Using fermentation method to prepare AP12 into the inactivated fermentation solution (IFS), fermentation solution (FS), inactivated mycelium solution (IMS), and mycelium solution (MS), and the results showed that all four fungal elicitor components (ECs) could promote A. paniculata growth, enhance antioxidant defense enzymes, and increase ADC content and yield, especially the IMS group that had the highest leaf area, whole plant dry weight, superoxide dismutase (SOD), catalase (CAT) enzyme activities, total lactone contents, and yields, which were 2.37-, 1.60-, 2.20-, 3.27-, 1.59-, and 2.65-fold of the control, respectively. The 14-deoxyandrographolide (NAD) in the host irrigated with MS was 3.35-fold that of the control. In addition, AP12-infected A. paniculata sterile seedlings could significantly increase ADC content and expression levels of key enzyme genes, especially on day 12, when the total lactone content of the host reached 88.881± 5.793 mg/g DW, while on day 6, CPS gene expression level reached 10.79-fold that of the control, in turn promoting the biosynthesis and accumulation of andrographolide. In conclusion, the endophytic fungus AP12 is beneficial to the growth and secondary metabolism of A. paniculata , which is helpful for the cultivation and application of the biological bacterial fertilizer in A. paniculata , providing a theoretical and research basis for the use of endophytic fungi as a microbial resource to improve the quality and yield of medicinal plants.

Fungal infections are a significant global public health challenge because of their widespread occurrence, morbidity, and profound social and economic consequences. Antifungal resistance is also an increasing concern, posing a substantial risk to public health. There is a growing interest in searching for new antifungal drugs isolated from natural sources. This study aimed to evaluate the antifungal activity of novel mollusk fractions against fungal strains resistant to nystatin and amphotericin B. In addition, the role of oxidative stress in the mechanism of damage was determined. The mucus from the garden snail Cornu aspersum (MCa/1-20) and the hemolymph fraction from the marine snail Rapana venosa (HLRv/3-100) were obtained and characterized via 12% sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) and mass spectrometric -analyses. The results demonstrate that the spores and biomass of both mollusk fractions have a significant fungicidal effect against Penicillium griseofulvum, and Aspergillus niger. Compared to the control group, the release of intracellular proteins and reducing sugars was significantly increased in the treated groups. The data showed increased levels of oxidative stress biomarkers (lipid peroxidation and oxidatively damaged proteins) and a downregulated antioxidant enzyme defense, corresponding to increased antifungal activity. To our knowledge, this is the first study evaluating oxidative stress as a factor in mollusk fractions’ antifungal activity.

Tomato yellow leaf curl virus disease (TYLCV) is a devastating disease in tomato industry development. Due to the lack of efficient chemical control agents, the prevention and control of this disease has become a major challenge in the industry. This study used the self-bred tomato variety “Nongbo Fen 18109” as experimental material. Through determination of endogenous hormone contents, defense enzyme activities, and viral load in tomato leaves as core indicators, screening experiments of plant immune elicitors were conducted, and further evaluation of the selected elicitors’ field control effects on TYLCV was performed. The results showed that 5% amino-oligosaccharin aqueous solution and 6% oligosaccharin-chain protein wettable powder could significantly regulate the balance of tomato endogenous hormones, increase indole-3-acetic acid (IAA), salicylic acid (SA) contents and peroxidase (POD) activity, reduce jasmonic acid (JA) and abscisic acid (ABA) levels, and effectively enhance plant resistance to TYLCV. When used in combination, these two elicitors achieved the best control effect, with only 6 diseased plants during the experimental period and an average CT value of 14.34 in virus detection, significantly superior to single elicitor treatments and the chemical agent moroxydine hydrochloride-copper treatment. This study identified an efficient TYLCV immune elicitor combination and its application effects, providing theoretical basis and practical technical support for constructing a green prevention and control system for tomato yellow leaf curl virus disease.