Harnessing Setaria as a Model for C₄ Plant Adaptation to Abiotic Stress

Climate change and the resulting abiotic stresses that emerge due to anthropogenic activities are the main causes of agricultural losses worldwide. Abiotic stresses such as water scarcity, extreme temperatures, high irradiance, saline soils, nutrient deprivation and heavy metal contamination compromise the development and productivity of crops on a global scale. In this scenario, understanding the response of C₄ plants to different abiotic stresses is of utmost importance, as they constitute major pillars of the global economy. To further our understanding of the response of C₄ monocots, Setaria viridis and Setaria italica have gradually emerged as powerful model species for elucidating the physiological, biochemical, and molecular mechanisms of plant adaptation to abiotic stresses. This review integrates recent findings on the morphophysiological, transcriptomic, and metabolic responses of S. viridis and S. italica to drought, elevated heat and light, saline soils, nutrient deficiencies and heavy metal contamination. Comparative analyses highlight conserved and divergent stress-response pathways between the domesticated S. italica and its wild progenitor S. viridis. Together, these findings reinforce Setaria as a versatile C₄ model for unraveling mechanisms of abiotic stress tolerance and highlight its potential as a genetic resource for developing climate-resilient cereal and bioenergy crops.