Differential drought responses in deep and shallow-rooted rice genotypes: enzymatic and non-enzymatic insights

This study was undertaken to understand the root-driven differential response of enzymatic and non-enzymatic adaptive systems to drought in rice using 30 contrasting deep and shallow-rooted rice genotypes from the temperate rice diversity of Western Himalayan Kashmir under drought stress conditions. Our analysis focused on root and shoot traits and the assessment of 12 biochemical parameters encompassing both enzymatic and non-enzymatic responses. Under drought stress, deep-rooted genotypes exhibited significantly higher mean root depths, root biomass, and root-to-shoot ratios than their shallow-rooted counterparts. Interestingly, most of the biochemical parameters displayed an increasing trend in deep-rooted genotypes but decreased or showed non-significant increases in shallow-rooted genotypes under drought stress. Drought stress induced substantial changes in root and shoot parameters, with more pronounced effects observed in root traits. Deep-rooted genotypes demonstrated a remarkable 176.7% increase in root depth under drought conditions, compared to a modest 25.7% increase in irrigated conditions. Moreover, both enzymatic and non-enzymatic parameters exhibited higher increases in deep-rooted genotypes than shallow-rooted ones under drought stress. Our study unveiled significant associations among root and shoot traits and biochemical parameters, emphasizing the crucial role of roots in maintaining cellular homeostasis under stress conditions. These findings provide insights into the root-driven modulation of differential biochemical response of rice under drought stress, providing a foundation for further investigations into the molecular mechanisms through a multi-omics approach.