Among abiotic stresses, heat stress is described as one of the major limiting factors of crop growth worldwide, as high temperatures elicit a series of physiological, molecular, and biochemical cascade events that ultimately result in reduced crop yield. There is growing interest among researchers in the use of beneficial microorganisms. Intricate and highly complex interactions between plants and microbes result in the alleviation of heat stress. Plant–microbe interactions are mediated by the production of phytohormones, siderophores, gene expression, osmolytes, and volatile compounds in plants. Their interaction improves antioxidant activity and accumulation of compatible osmolytes such as proline, glycine betaine, soluble sugar, and trehalose, and enriches the nutrient status of stressed plants. Therefore, this review aims to discuss the heat response of plants and to understand the mechanisms of microbe-mediated stress alleviation on a physio-molecular basis. This review indicates that microbes have a great potential to enhance the protection of plants from heat stress and enhance plant growth and yield. Owing to the metabolic diversity of microorganisms, they can be useful in mitigating heat stress in crop plants. In this regard, microorganisms do not present new threats to ecological systems. Overall, it is expected that continued research on microbe-mediated heat stress tolerance in plants will enable this technology to be used as an ecofriendly tool for sustainable agronomy.

Drought is one of the most detrimental factors that causes significant effects on crop development and yield. However, the negative effects of drought stress may be alleviated with the aid of exogenous melatonin (MET) and the use of plant-growth-promoting bacteria (PGPB). The present investigation aimed to validate the effects of co-inoculation of MET and Lysinibacillus fusiformis on hormonal, antioxidant, and physio-molecular regulation in soybean plants to reduce the effects of drought stress. Therefore, ten randomly selected isolates were subjected to various plant-growth-promoting rhizobacteria (PGPR) traits and a polyethylene-glycol (PEG)-resistance test. Among these, PLT16 tested positive for the production of exopolysaccharide (EPS), siderophore, and indole-3-acetic acid (IAA), along with higher PEG tolerance, in vitro IAA, and organic-acid production. Therefore, PLT16 was further used in combination with MET to visualize the role in drought-stress mitigation in soybean plant. Furthermore, drought stress significantly damages photosynthesis, enhances ROS production, and reduces water stats, hormonal signaling and antioxidant enzymes, and plant growth and development. However, the co-application of MET and PLT16 enhanced plant growth and development and improved photosynthesis pigments (chlorophyll a and b and carotenoids) under both normal conditions and drought stress. This may be because hydrogen-peroxide (H₂O₂), superoxide-anion (O²⁻), and malondialdehyde (MDA) levels were reduced and antioxidant activities were enhanced to maintain redox homeostasis and reduce the abscisic-acid (ABA) level and its biosynthesis gene NCED3 while improving the synthesis of jasmonic acid (JA) and salicylic acid (SA) to mitigate drought stress and balance the stomata activity to maintain the relative water states. This may be possible due to a significant increase in endo-melatonin content, regulation of organic acids, and enhancement of nutrient uptake (calcium, potassium, and magnesium) by co-inoculated PLT16 and MET under normal conditions and drought stress. In addition, co-inoculated PLT16 and MET modulated the relative expression of DREB2 and TFs bZIP while enhancing the expression level of ERD1 under drought stress. In conclusion, the current study found that the combined application of melatonin and Lysinibacillus fusiformis inoculation increased plant growth and could be used to regulate plant function during drought stress as an eco-friendly and low-cost approach.

Background: A renewed focus on medicinal mushrooms has brought forth a sustainable health dimension. Conventional health strategies are insufficiently integrated with sustainable health promotion. The health-promoting outcome of mushrooms has fascinated many groups during the past few years because of various primary and secondary metabolites in different cellular components. They contain many bioactive metabolites, including proteins (cytokines, ergothioneine), fibers, moisture, carbohydrates (uronic acid), folate, thiamine, ascorbic acid, vitamin D, calcium, potassium, polysaccharides (G. lucidum polysaccharides, alpha and beta glucans, and lentinan) polyketides, polyphenols (Protocatechuic acid, inonoblins A–vanillic acid, phelligridins D, E, and G, hydroxybenzoic acid, gallic acid, tannic acid, hispidine, gentisic acid, and tocopherol), nucleotides (adenosine, cordycepin), lovastatin, steroids, alkaloids, and sesquiterpenes. Objective: This study was conducted to gather information on the current knowledge of medicinal mushrooms, with respect to their antioxidant properties. Conclusions: The results indicated that mushrooms are a promising source of natural antioxidants. Of all mushrooms, the Ganoderma tsugae Murill exhibited an excellent antioxidant potential of 93.7–100% at 20 mg/mL.

Light is crucial for higher plants, driving photosynthesis and serving as a powerful sensory signal that profoundly modulates growth, development, physiological functions, hormone activation, and biochemical pathways. Various light parameters—quality, intensity, composition, and photoperiod—exert a tremendous influence on plant growth and development, particularly in industrial hemp (Cannabis sativa L.). C. sativa, a crop of historical significance and unparalleled versatility, holds immense value in the food, fiber, and medicinal industries. The cultivation of medicinal cannabis is burgeoning in controlled environments due to evolving healthcare regulations. Optimal light conditions significantly enhance both yield and harvest quality, notably increasing the density of apical inflorescences and the ratio of inflorescence to total aboveground biomass. C. sativa metabolites, especially phenolic and terpene compounds and Phytocannabinoids like CBD (cannabidiol), THC (tetrahydrocannabinol), and CBG (cannabigerol), possess immense medicinal value. Secondary metabolites in C. sativa predominantly accumulate in the trichomes of female flowers and surrounding sugar leaves, underscoring the critical need to boost inflorescence weight and metabolite concentrations while ensuring product consistency. Different light parameters distinctly impact C. sativa’s metabolic profile, providing a robust foundation for understanding the optimal conditions for synthesizing specific secondary metabolites. While the effects of light measurement on various crops are well-established, scientific evidence specifically relating to light quality effects on C. sativa morphology and secondary metabolite accumulation remains scarce. In this review, we critically summarized how different light properties can alter cannabis growth (vegetative and reproductive), physiology and metabolism. Furthermore, the mechanisms by which specific wavelengths influence growth, development, and secondary metabolite biosynthesis in C. sativa are not fully elucidated, which could be a prospective task for future researchers. Our review paves the way for a profound understanding of light’s influence on C. sativa growth and advancements in greenhouse settings to maximize metabolite production for commercial use.

Maize is the third most common cereal crop worldwide, after rice and wheat, and plays a vital role in preventing global hunger crises. Approximately 50% of global crop yields are reduced by drought stress. Bacteria as biostimulants for biopriming can improve yield and enhance sustainable food production. Further, seed biopriming stimulates plant defense mechanisms. In this study, we isolated bacteria from the rhizosphere of Artemisia plants from Pohang beach, Daegu, South Korea. Twenty-three isolates were isolated and screened for growth promoting potential. Among them, bacterial isolate SH-6 was selected based on maximum induced tolerance to polyethylene glycol-simulated drought. SH-6 showed ABA concentration = 1.06 ± 0.04 ng/mL, phosphate solubilizing index = 3.7, and sucrose concentration = 0.51 ± 0.13 mg/mL. The novel isolate SH-6 markedly enhanced maize seedling tolerance to oxidative stress owing to the presence of superoxide dismutase, catalase, and ascorbate peroxidase activities in the culture media. Additionally, we quantified and standardized the biopriming effect of SH-6 on maize seeds. SH-6 significantly increased maize seedling drought tolerance by up to 20%, resulting in 80% germination potential. We concluded that the novel bacterium isolate SH-6 (gene accession number (OM757882) is a biostimulant that can improve germination performance under drought stress.

Drought stress significantly retards the plant production. Melatonin is a vital hormone, signaling molecule, and bio-regulator of diverse physiological growth and development processes. Its role in boosting agronomic traits under diverse stress conditions has received considerable attention. However, the underlying molecular mechanism of action and how they increase drought stress tolerance has not been fully interpreted. The current study aimed to ascertain the protective role of melatonin in fortifying the antioxidant defense system, modulating the phytohormone profile, and improving agronomic traits of tomato seedlings under drought stress. After the V1 stage (1st leaf fully emerged), tomato seedlings were exposed to PEG-6000 to mimic drought-induced stress (DR 10% and DR 20%), followed by exogenous application of 100 µM soil drench. Drought-induced stress negatively impacted tomato seedlings by reducing growth and development and biomass accumulation, diminishing salicylic acid (SA) and chlorophyll levels, and dramatically lowering the antioxidant defense ability. However, melatonin protected them by activating the defense system, which decreased the oxidative burst and increased the activities of SOD, CAT, and APX. Administration of 100 µM melatonin by soil drench most remarkably downregulated the transcription factors of SlDREB3 and SlNCED3. This study has validated the moderating potential of melatonin against drought-induced stress by maintaining plant growth and development, enhancing hormone levels, elevating antioxidant enzyme activities, and suppressing the relative expression of drought-responsive genes. These findings also provide a basis for the potential use of MT in agricultural research and other relevant fields of study.