Effects of Dufulin on Oxidative Stress and Metabolomic Profile of Tubifex

Bacillus velezensis HN-2: a potent antiviral agent against pepper veinal mottle virus

Background

Pepper veinal mottle virus (PVMV) belongs to the genus Potyvirus within the family Potyviridae and is a major threat to pepper production, causing reduction in yield and fruit quality; however, efficient pesticides and chemical treatments for plant protection against viral infections are lacking. Hence, there is a critical need to discover highly active and environment-friendly antiviral agents derived from natural sources. Bacillus spp. are widely utilized as biocontrol agents to manage fungal, bacterial, and viral plant diseases. Particularly, Bacillus velezensis HN-2 exhibits a strong antibiotic activity against plant pathogens and can also induce plant resistance.

Methods

The experimental subjects employed in this study were Bacillus velezensis HN-2, benzothiadiazole, and dufulin, aiming to evaluate their impact on antioxidant activity, levels of reactive oxygen species, activity of defense enzymes, and expression of defense-related genes in Nicotiana benthamiana. Furthermore, the colonization ability of Bacillus velezensis HN-2 in Capsicum chinense was investigated.

Results

The results of bioassays revealed the robust colonization capability of Bacillus velezensis HN-2, particularly in intercellular spaces, leading to delayed infection and enhanced protection against PVMV through multiple plant defense mechanisms, thereby promoting plant growth. Furthermore, Bacillus velezensis HN-2 increased the activities of antioxidant enzymes, thereby mitigating the PVMV-induced ROS production in Nicotiana benthamiana. Moreover, the application of Bacillus velezensis HN-2 at 5 dpi significantly increased the expression of JA-responsive genes, whereas the expression of salicylic acid-responsive genes remained unchanged, implying the activation of the JA signaling pathway as a crucial mechanism underlying Bacillus velezensis HN-2-induced anti-PVMV activity. Immunoblot analysis revealed that HN-2 treatment delayed PVMV infection at 15 dpi, further highlighting its role in inducing plant resistance and promoting growth and development.

Conclusions

These findings underscore the potential of Bacillus velezensis HN-2 for field application in managing viral plant diseases effectively.

Dufulin enhances salt resistance of rice

Dufulin is a newly developed plant antiviral agent, which is widely used in the control of many viral crop diseases. Existing research mainly focuses on its antiviral effect, but research in relation to resistance to abiotic stress is unclear. This study was based on the treatment of rice with salt (NaCl), and exogenous application of Dufulin as a stress-resistant agent. The effect of Dufulin on salt stress of rice was revealed. There were 1997 differential genes detected, including 1449 up-regulated and 548 down-regulated. After the application of Dufulin to rice, when salt stress was applied, peroxidase activity was increased and superoxide dismutase activity was reduced; GO and KEGG analyses indicated that the stimulated genes are related to the stress resistance pathway, thus improving the ability of rice to resist salt stress. Quantitative real-time PCR analysis was used to verify the dynamic changes of growth- and stress-resistance-related genes, among which integral membrane protein DUF6 containing protein, OsHKT1;4 (Na⁺ transporter) and zinc-finger protein were verified to increase by more than three times, and OsIAA1 and OsIAA9 were verified as down-regulated. Measuring the length of root, stem and leaf, and OsIAA1 and OsIAA9 expression showed that Dufulin promoted rice growth. After that, Dufulin could enhance the salt resistance of rice by regulating the expression of integral membrane protein DUF6 containing protein, OsHKT1;4, zinc-finger protein and other related genes under salt stress. The results elucidated the mechanism of Dufulin action during salt stress in rice at the transcriptional level.

Metabolomic Studies for the Evaluation of Toxicity Induced by Environmental Toxicants on Model Organisms

Environmental pollution causes significant toxicity to ecosystems. Thus, acquiring a deeper understanding of the concentration of environmental pollutants in ecosystems and, clarifying their potential toxicities is of great significance. Environmental metabolomics is a powerful technique in investigating the effects of pollutants on living organisms in the environment. In this review, we cover the different aspects of the environmental metabolomics approach, which allows the acquisition of reliable data. A step-by-step procedure from sample preparation to data interpretation is also discussed. Additionally, other factors, including model organisms and various types of emerging environmental toxicants are discussed. Moreover, we cover the considerations for successful environmental metabolomics as well as the identification of toxic effects based on data interpretation in combination with phenotype assays. Finally, the effects induced by various types of environmental toxicants in model organisms based on the application of environmental metabolomics are also discussed.