Role of silica nanoparticles in enhancing drought tolerance of cereal crops

Cereal crops are essential for providing essential nutrients and energy in the daily human diet. Additionally, they have a crucial role as a significant constituent of cattle feed, hence enhancing meat production. Drought, being an abiotic stressor, adversely affects the growth and yield of numerous crops on a global scale. This issue poses a significant and pressing obstacle to maintaining global cereal crop production and ensuring food security. Nanoparticles have become a valuable resource for improving cereal crop yield and productivity under ongoing rapid climate change and escalating drought conditions. Among these, silica nanoparticles (SiNPs) have demonstrated their potential for agricultural applications in regions with limited water availability. Drought stress has detrimental effects on cereal crops, impacting their growth, metabolic, and physiological processes, hampering water and nutrient absorption, disrupting cellular membranes, damaging the photosynthetic apparatus, and reducing antioxidant activities by altering gene expression. SiNPs help preserve cellular membranes, regulate water balance, and improve water and nutrient absorption, resulting in a substantial enhancement in plant growth under water-deficit conditions. SiNPs also protect the photosynthetic system and enhance its efficiency, facilitate the accumulation of phenolics, hormones, osmolytes, antioxidant activities, and gene expression, thus empowering plants with increased resistance to drought stress. Moreover, SiNPs decrease leaf water loss by promoting stomatal closure, primarily by fostering the accumulation of abscisic acid (ABA) and mitigating oxidative stress damage by activating the antioxidant defence system and reducing reactive oxygen species (ROS). However, a limited number of studies examine the role of SiNPs in cereal crops under drought stress conditions. In this review, we highlighted the promising potential of SiNPs to improve cereal crop resilience by changing morpho-histological traits, antioxidant properties, and gene expression to maintain food security in drought-prone areas. This study will aid researchers in using SiNPs as an environmentally benign way to improving drought resistance in cereal crops in order to fulfill global food supply needs.