Bio-stimulants enhance cold tolerance in tobacco through antioxidant defense and photosynthetic regulation.

Cold stress (CS) is a significant obstacle in tobacco (Nicotiana tabacum L.) farming, significantly affecting plant development, photosynthetic activity, and cellular redox balance. In recent decades, bio-stimulants have created environmentally friendly substances that make the plant resistant to abiotic stresses, such as cold stress. The recent developments highlight bio-stimulants as a sustainable solution to improve cold stress tolerance in tobacco production. These substances promote plant growth, thereby increasing plant resilience to unfavorable temperature conditions. This review assesses the role of bio-stimulants in improving cold stress tolerance in tobacco, focusing on physiological, biochemical, and molecular responses. It summarizes the effects of various bio-stimulants on plant growth, antioxidant defense systems, and photosynthetic performance under low-temperature conditions. The enhancement of enzymatic antioxidants and non-enzymatic antioxidants by bio-stimulants helps overcome oxidative damage. Evidence in molecular biology studies to understand bio-stimulant-mediated regulation of stress responsive genes is also critically discussed in order to understand the role bio-stimulants play in enhancing the genetic potential of tobacco to cold stress. This review presents an integrated scheme of the multifarious functions of bio-stimulants in improving cold stress tolerance of tobacco. It also highlights existing knowledge gaps and provides research directions on how to explore efficient, sustainable, and climate resilient tobacco production systems in the future.