This review delves into the role of plant growth-promoting microbes (PGPMs) in sustainable agriculture by enhancing soil health, improving plant stress tolerance, and controlling diseases. PGPMs, which include bacteria, fungi, and other microorganisms, are increasingly recognized as important contributors to promoting eco-friendly agricultural practices. Their ability to improve nutrient availability, stimulate plant growth, and protect crops from environmental stressors makes them a cornerstone for resilient and efficient farming systems. By reducing dependency on synthetic fertilizers and pesticides, PGPMs play a vital role in preserving environmental resources, minimizing greenhouse gas (GHG) emissions, and combating climate change’s negative impacts. This article thoroughly explores the complex interactions between PGPMs, soil nutrients, plant pathogens, and abiotic stressors. It also examines how these interactions influence phytohormone production and signaling pathways, ultimately impacting crop growth and development. Furthermore, this review discusses how PGPMs enhance nutrient uptake, modulate plant immune responses, and improve stress resilience, offering a holistic understanding of their multifaceted contributions to farming. By synthesizing current research and highlighting future directions, this review underscores the potential of PGPMs to revolutionize agricultural activities, ensuring food security and environmental sustainability in the face of global challenges.

Melatonin was found in plants in the late 1990s, but its function, signaling, and interaction with other phytohormones still unclear. Melatonin research in plants has increased substantially in recent years, including reports on the impact of this putative plant hormone under biotic and abiotic stress situations. Temperature extremes, salt, drought, hypoxia or anoxia, nutrient deficiency, herbicides, UV radiation stress, and heavy metal toxicity are all important obstacles to horticulture crop production worldwide. To deal with these environmental challenges, plants have evolved complex signaling networks. Phytohormones are essential for controlling plant growth, development, and stress responses. Melatonin, a pleiotropic chemical present in a variety of species, has recently emerged as a powerful regulator of plant abiotic stress tolerance. The purpose of this review is to investigate the interplay between melatonin and phytohormones in the control of abiotic stress responses in horticultural crops. We explore the interactions of melatonin with several phytohormones under various abiotic stresses.

This study aims to determine the influence of grafting and nano-silicon fertilizer on the growth and production of tomatoes (Solanumlycopersicum L.) under salinity conditions. A commercial tomato hybrid (cv. Strain B) was used as a scion and two tomato phenotypes were used as rootstocks: S. pimpinellifolium and Edkawy. The rootstock effect was evaluated by growing plants at two NaCl concentrations plus the control (0, 4000, and 8000 ppm NaCl). Nano-silicon foliar application (0.5 ppm) after 20, 28, and 36 days from transplanting was also used to mitigate salinity stress. Antioxidants, hormones, and proline were evaluated for a better understanding of the physiological changes induced by salinity and grafting. The results showed that grafting either on S. pimpinellifolium or Edkawy combined with nano-silicon application enhanced shoot and root growth, fruit yield, and fruit quality. The Edkawy rootstock was more effective than the S. pimpinellifolium rootstock in terms of counteracting the negative effect of salinity. Higher levels of mineral contents, GA3, ABA, and proline were detected in shoots that were subjected to grafting and nano-silicon application compared to the control treatment. This study indicates that grafting and nano-silicon application hold potential as alternative techniques to mitigate salt stress in commercial tomato cultivars.

Silicon plays a crucial role in enhancing plant tolerance to various abiotic and biotic stresses, including drought, salinity, heavy metals, and pathogen/pest attacks. Its application has shown promising results in improving stress tolerance and productivity in medicinal plants. This review synthesizes findings from numerous studies investigating the mechanisms by which silicon confers stress tolerance, including the regulation of antioxidant systems, water relations, nutrient homeostasis, phytohormone signaling, and stress-responsive gene expression. Additionally, it examines the effects of silicon supplementation on the production of valuable secondary metabolites and essential oils in medicinal plants. Silicon application can significantly mitigate stress-induced damage in plants, including medicinally important species such as borage, honeysuckle, licorice, Damask rose, savory, basil, and eucalyptus. The deposition of silicon in cell walls provides physical reinforcement and acts as a barrier against pathogen invasion and insect herbivory. Furthermore, silicon fertilization can enhance the production of valuable secondary metabolites in medicinal crops under stress conditions. The findings underscore the potential of silicon fertilization as a sustainable strategy for improving the productivity and quality of medicinal crops under changing environmental conditions, highlighting the need for further research to elucidate the molecular mechanisms underlying silicon-mediated stress tolerance and practical applications in medicinal plant cultivation.

The primary worldwide variables limiting plant development and agricultural output are the ever-present threat that environmental stressors such as salt (may trigger osmotic stress plus ions toxicity, which impact on growth and yield of the plants), drought (provokes water stress, resulting in lowering photosynthesis process and growth rate), heavy metals (induced toxicity, hindering physiological processes also lowering crop quantity and quality), and pathogens (induce diseases that may significantly affect plant health beside productivity). This review explores the integrated effects of these stressors on plant productivity and growth rate, emphasizing how each stressor exceptionally plays a role in physiological responses. Owing to developments in technology that outclass traditional breeding methods and genetic engineering techniques, powerful alleviation strategies are vital. New findings have demonstrated the remarkable role of nanoparticles in regulating responses to these environmental stressors. In this review, we summarize the roles and various applications of nanomaterials in regulating abiotic and biotic stress responses. This review discusses and explores the relationship between various types of nanoparticles (metal, carbon-based, and biogenic) and their impact on plant physiology. Furthermore, we assess how nanoparticle technology may play a role in practices of sustainable agriculture by reducing the amount of compounds used, providing them with a larger surface area, highly efficient mass transfer abilities, and controlled, targeted delivery of lower nutrient or pesticide amounts. A review of data from several published studies leads to the conclusion that nanoparticles may act as a synergistic effect, which can effectively increase plant stress tolerance and their nutritional role.

Phenolic compounds are proving to be increasingly important for human health and in crop development, defense and adaptation. In spite of the economical importance of Brassica crops in agriculture, the mechanisms involved in the biosynthesis of phenolic compounds presents in these species remain unknown. The genetic and metabolic basis of phenolics accumulation was dissected through analysis of total phenolics concentration and its individual components in leaves, flower buds and seeds of a double haploid (DH) mapping population of Brassica oleracea. The quantitative trait loci (QTL) that had an effect on phenolics concentration in each organ were integrated, resulting in 33 consensus QTLs controlling phenolics traits. Most of the studied compounds had organ-specific genomic regulation. Moreover, this information allowed us to propose candidate genes and to predict the function of genes underlying the QTL. A number of previously unknown potential regulatory regions involved in phenylpropanoid metabolism were identified and this study illustrates how plant ontogeny can affect a biochemical pathway.