Halotolerant Pseudomonas koreensis S4T10 mitigate salt and drought stress in Arabidopsis thaliana.

Salt and drought are documented among the most detrimental and persistent abiotic stresses for crop production. Here, we investigated the impact of Pseudomonas koreensis strain S4T10 on plant performance under salt and drought stress. Arabidopsis thaliana Col-0 wild type and atnced3 mutant plants were inoculated with P. koreensis or tap water and exposed to NaCl (100 mM) for five days and drought stress by withholding water for seven days. P. koreensis significantly enhanced plant biomass and photosynthetic pigments under salt and drought stress conditions. Moreover, P. koreensis activated the antioxidant defence by modulating glutathione (GSH), superoxide dismutase (SOD), peroxidase (POD), and polyphenol oxidase (PPO) activities to scavenge the reactive oxygen species produced due to the stress. In addition, the application of P. koreensis upregulated the expression of genes associated with antioxidant responses, such as AtCAT1, AtCAT3, and AtSOD. Similarly, genes linked to salt stress, such as AtSOS1, AtSOS2, AtSOS3, AtNHX1, and AtHKT1, were also upregulated, affirming the positive role of P. koreensis S4T10 in streamlining the cellular influx and efflux transport systems during salt stress. Likewise, the PGPB inoculation was observed to regulate the expression of drought-responsive genes AtDREB2A, AtDREB2B, and ABA-responsive genes AtAO3, AtABA3 indicating that S4T10 enhanced drought tolerance via modulation of the ABA pathway. The results of this study affirm that P. koreensis S4T10 could be further developed as a biofertilizer to mitigate salt and drought stress at the same time.

Plant-Entomopathogenic Fungi Interaction: Recent Progress and Future Prospects on Endophytism-Mediated Growth Promotion and Biocontrol.

Entomopathogenic fungi, often acknowledged primarily for their insecticidal properties, fulfill diverse roles within ecosystems. These roles encompass endophytism, antagonism against plant diseases, promotion of the growth of plants, and inhabitation of the rhizosphere, occurring both naturally and upon artificial inoculation, as substantiated by a growing body of contemporary research. Numerous studies have highlighted the beneficial aspects of endophytic colonization. This review aims to systematically organize information concerning the direct (nutrient acquisition and production of phytohormones) and indirect (resistance induction, antibiotic and secondary metabolite production, siderophore production, and mitigation of abiotic and biotic stresses) implications of endophytic colonization. Furthermore, a thorough discussion of these mechanisms is provided. Several challenges, including isolation complexities, classification of novel strains, and the impact of terrestrial location, vegetation type, and anthropogenic reluctance to use fungal entomopathogens, have been recognized as hurdles. However, recent advancements in biotechnology within microbial research hold promising solutions to many of these challenges. Ultimately, the current constraints delineate potential future avenues for leveraging endophytic fungal entomopathogens as dual microbial control agents.

Role of salicylic acid in improving the yield of two mung bean genotypes under waterlogging stress through the modulation of antioxidant defense and osmoprotectant levels.

Waterlogging (WL) is a major hindrance to the growth and development of leguminous crops, including mung bean. Here, we explored the effect of salicylic acid (SA) pretreatment on growth and yield output of two elite mung bean genotypes (BU Mung bean-4 and BU Mung bean-6) subjected to WL stress. SA pretreatment significantly improved shoot dry weight, individual leaf area, and photosynthetic pigment contents in both genotypes, while those improvements were higher in BU Mung bean-6 when compared with BU Mung bean-4. We also found that SA pretreatment significantly reduced the reactive oxygen species-induced oxidative burden in both BU Mung bean-6 and BU Mung bean-4 by enhancing peroxidase, glutathione S-transferase, catalase, and ascorbate peroxidase activities, as well as total flavonoid contents. SA pretreatment further improved the accumulation of proline and free amino acids in both genotypes, indicating that SA employed these osmoprotectants to enhance osmotic balance. These results were particularly corroborated with the elevated levels of leaf water status and leaf succulence in BU Mung bean-6. SA-mediated improvement in physiological and biochemical mechanisms led to a greater yield-associated feature in BU Mung bean-6 under WL conditions. Collectively, these findings shed light on the positive roles of SA in alleviating WL stress, contributing to yield improvement in mung bean crop.

Salicylic Acid Priming Improves Cotton Seedling Heat Tolerance through Photosynthetic Pigment Preservation, Enhanced Antioxidant Activity, and Osmoprotectant Levels.

The escalating global temperatures associated with climate change are detrimental to plant growth and development, leading to significant reductions in crop yields worldwide. Our research demonstrates that salicylic acid (SA), a phytohormone known for its growth-promoting properties, is crucial in enhancing heat tolerance in cotton (Gossypium hirsutum). This enhancement is achieved through modifications in various biochemical, physiological, and growth parameters. Under heat stress, cotton plants typically show significant growth disturbances, including leaf wilting, stunted growth, and reduced biomass. However, priming cotton plants with 1 mM SA significantly mitigated these adverse effects, evidenced by increases in shoot dry mass, leaf-water content, and chlorophyll concentrations in the heat-stressed plants. Heat stress also prompted an increase in hydrogen peroxide levels-a key reactive oxygen species-resulting in heightened electrolyte leakage and elevated malondialdehyde concentrations, which indicate severe impacts on cellular membrane integrity and oxidative stress. Remarkably, SA treatment significantly reduced these oxidative stresses by enhancing the activities of critical antioxidant enzymes, such as catalase, glutathione S-transferase, and ascorbate peroxidase. Additionally, the elevated levels of total soluble sugars in SA-treated plants enhanced osmotic regulation under heat stress. Overall, our findings reveal that SA-triggered protective mechanisms not only preserve photosynthetic pigments but also ameliorate oxidative stress and boost plant resilience in the face of elevated temperatures. In conclusion, the application of 1 mM SA is highly effective in enhancing heat tolerance in cotton and is recommended for field trials before being commercially used to improve crop resilience under increasing global temperatures.