Abiotic Stress Tolerance in Foxtail Millet (Setaria italica L.): From Molecular Mechanisms to Climate-Resilient Breeding

Abiotic stresses caused by climate change pose a significant challenge to global food security, making it necessary to develop stress-resistant crops. Foxtail millet (Setaria italica (L.) P. Beauv.) is a drought-tolerant C4 cereal and serves as a model crop for elucidating stress adaptation mechanisms and promoting climate-resilient agricultural solutions. This paper reviews the tolerance mechanisms of foxtail millet to abiotic stresses. Physiologically, the species exhibits excellent water-use efficiency, requiring 75% less irrigation than traditional cereals, achieved through enhanced osmotic adjustment via soluble substance accumulation and the maintenance of ion homeostasis. Morphological adaptations include reduced leaf area, adjusted stomatal density, well-developed root systems, and specialized anatomical features that optimize water conservation. At the molecular level, stress tolerance involves complex transcriptional networks mediated by multiple transcription factor family members, including those (NF-Y, DREB, NAC, WRKY, MYB) that coordinate stress-responsive gene expression, antioxidant defense systems, and osmotic adjustment pathways. Furthermore, this review summarizes multi-omics characteristics, including genomics (such as QTL mapping and GWAS), proteomics, transcriptomics, metabolomics, and regulatory networks, for foxtail millet under abiotic stress tolerance. Additionally, reproductive resilience is maintained through efficient mobilization of stem reserves to panicles, phenological plasticity in flowering timing, and preserved gametic viability under thermal stress. Combining advanced molecular breeding with the inherent tolerance of foxtail millet positions this crop as both a solution to climate change and a genetic resource for enhancing the stress resistance of other cereals. These findings establish foxtail millet as a valuable model for developing sustainable agricultural technologies essential for food security under projected climate scenarios.