Unraveling the mysteriescomplexities: Morpho-physiological and proteomic responses of Pearl millet (Pennisetum glaucum) to dual drought and salt stress

Charlie Sithole Rotondwa Rabelani Sinthumule Joseph Gaorongwe Oziniel Ruzvidzo Tshegofatso Bridget Dikobe ^*

• Department of Botany, School of Biological Sciences, North West University, Mmabatho, South Africa

Agriculture is crucial for sustaining the world's growing population, however various abiotic and biotic stressors, such as drought and salt, significantly impact crop yields. Pearl millet, a highnutrient-rich cropand, is known for its drought-tolerant crop, ce and is importanceessential as a food source in arid regions. Understanding its response mechanisms to drought and salt stress can helpis important for devising e strategies for improved crop performance under water deficit and saline environments. This study investigated the morphological, physiological, and molecular responses of pearl millet pearl millet's morphological, physiological, and molecular responses induced subjected to by individual and combined drought and salt stresses for 25 days. Significant reductions in Various morphological traits, such as plant height, shoot and root fresh weights and lengths, and leaf numbers were affectedobserved. Furthermore, key physiological parameters, includingwere mostly inhibited, such as relative water content, chlorophyll content, stomatal conductance, photosynthesis, and transpiration rates notably declined, indicating a complex interaction between stress factors and water regulation mechanisms. Protein expression profile analysis showed similar bandingdifferential upregulation and downregulation patterns between the control and treated stressed pearl millet plants., suggesting upregulation/downregulation of various proteins. Gene ontology mapping identified key biological processes, molecular functions, and cellular components of differentially expressed proteins associated with individual and combined stresses. Notably, a high number of unclassified proteins were identified, indicating the presence of potentially novel proteins involved in stress adaptation. Catalytic and binding activities were the predominant molecular functions detected across treatments suggesting their central role in stress response. Moreover, differentially expressed proteins highlighted potential mechanismsThese highlighted potential mechanisms of tolerance and adaptation in pearl millet. Overall, this study provides a comprehensive understanding of the detrimental effects of drought and salinity on pearl millet at the morphological, physiological, and proteomic levels, uncovering previously unexplored proteomic responses. These insights offering valuable molecular marker targetsinsights for breeding programs aimend at enhancing stress response strategiestolerance in pearl millet and related crops.