Review on synergistic interactions of dark septate endophyte in promoting plant growth and drought resilience in the era of climate change

Abstract The phenomenon of global climate change has increased the frequency and intensity of extreme environmental events, including higher temperatures and irregular precipitation. Among the major abiotic stressors, drought represents one of the most critical threats to plant growth and crop productivity. A promising strategy to improve plant resilience and productivity under drought is the application of beneficial endophytic fungi. Microbial technologies, which are crucial for nutrient cycling and plant health, have garnered increasing attention over the past decade. Dark septate endophytes (DSEs) are a group of root-associated fungi that frequently inhabit environments with limited nutrients or high levels of stress. Through their symbiotic relationships with host plants, these fungi promote plant growth and modulate stress tolerance, including drought. Morphologically, DSE colonization results in increased root and shoot biomass, enhanced branching, and more vigorous leaf development. Physiologically, they stimulate the activity of antioxidant enzymes such as superoxide dismutase and peroxidase, while simultaneously enhancing the accumulation of osmoprotec5ants such as soluble sugars, and promoting the synthesis of extracellular polymeric substances (EPS). Co-inoculation with DSEs has also improves nutrient uptake, particularly nitrogen, phosphorus, and potassium. Although these findings are promising, most studies have been conducted in vitro or greenhouse conditions, which limits the understanding of DSE performance under actual field environtments. Therefore, future research should prioritize field-based investigations aimed at developing reliable, cost-effective, and scalable DSE-based bioinoculants. Such advancements are crucial for fully understanding the potential of DSEs as biological tools in sustainable agriculture and to contribute to global food security in the era of climate change.