Abiotic Stress, Crop Resilience and Food Security: A Comprehensive Review

Abiotic stress response mechanisms, molecular mitigation, and future strategies in millets

Abiotic stresses, such as drought, salinity, temperature extremes, heavy metals, and pesticide toxicity, severely impact plant growth and productivity, primarily through the accumulation of reactive oxygen species (ROS) and metabolic imbalances. In the era of climate change and declining agricultural sustainability, the development of stress-resilient crops has become essential for ensuring global food and nutritional security. Millets, also known as ‘super grain’ or ‘miracle grain’ due to their nutritional value, are recognized for their inherent resilience and exhibit superior adaptability in arid and semi-arid ecosystems towards these abiotic stresses. It is due to their C4 photosynthetic efficiency, rapid life cycles, and deep root architecture. These cereals deploy integrated morphological, physiological, biochemical, and molecular mechanisms, including antioxidant defense systems, osmolyte accumulation, stress-responsive gene expression, and hormonal regulation to maintain homeostasis under stress. Despite these traits, millet improvement lags behind that of major cereals due to limited breeding efforts and underdeveloped molecular resources. This review focuses on recent advances in stress tolerance mechanisms, highlighting omics-driven insights, microbial and phytohormonal mitigation strategies, and exploring genome editing and modern breeding tools, such as CRISPR/Cas9 and genome-wide association studies (GWAS), for developing climate-resilient millet cultivars suitable for sustainable agriculture and future food security. The article explores the development of climate-resilient millet varieties by integrating molecular innovations into traditional agronomic practices, which will provide future benefits framework for developing new varieties. Overall, the article will deepen understanding of the molecular processes underlying stress responses and provide targeted solutions to enhance stress tolerance in millets.

Plant Physiological Responses to Abiotic Stress for Climate-Resilient Agriculture: An Integrative Review

Climate change is increasing the frequency, intensity, and co-occurrence of drought, salinity, heat, cold, flooding, and other abiotic constraints that destabilize crop productivity. Because crop failure emerges from physiological dysfunction before it becomes visible as yield loss, understanding plant physiological responses provides a critical bridge between basic stress biology and climate-resilient agriculture. This study used a qualitative library-research design with an integrative thematic synthesis of 35 peer-reviewed references, emphasizing recent literature while retaining foundational studies required to explain core mechanisms. Literature was organized around five analytical themes: stress perception and signaling, water relations and gas exchange, photosynthetic and metabolic stability, ionic and redox homeostasis, and recovery/acclimation under single and combined stresses. The synthesis shows that abiotic stresses differ in their primary injuries but converge on a limited set of physiological bottlenecks: loss of cellular water status, stomatal and mesophyll limitations to CO₂ diffusion, disruption of photosystems and respiration, membrane destabilization, ion imbalance, excessive reactive oxygen species, and altered source–sink relations. Resilient plants avoid catastrophic failure through coordinated stomatal regulation, root-system plasticity, osmotic adjustment, ion exclusion and compartmentation, antioxidant defense, heat-shock and cold-acclimation programs, hypoxia responses, hormonal crosstalk, and stress memory. Importantly, responses to combined stresses cannot be predicted by simply adding single-stress responses; the dominant stressor, stress sequence, developmental stage, and genotype can change both the direction and magnitude of acclimation. For climate-resilient agriculture, the most promising translation is therefore not selection for a single stress marker, but physiology-informed breeding and management that target yield stability, water-use efficiency, photosynthetic persistence, recovery capacity, and multi-stress tolerance. Integration of high-throughput phenotyping, genomic breeding, CRISPR-based editing, beneficial microorganisms, biostimulants, priming, and climate-smart crop management can accelerate the conversion of physiological knowledge into field resilience. The review concludes that future research should prioritize realistic stress combinations, recovery dynamics, reproductive-stage sensitivity, genotype-by-environment interactions, and field validation of mechanistic traits.

RELATIONSHIPS BETWEEN PHYSIOLOGY, GROWTH, AND YIELD OF CEREAL CROPS UNDER WATERLOGGING STRESS

Global food security is increasingly threatened by abiotic stresses, particularly waterlogging, which poses significant challenges to cereal crop production. Waterlogging is one of the primary abiotic stresses that significantly influence the interrelationships among plant physiology, growth, and yield. This review aims to examine the relationships among these three aspects in cereal crops, with an emphasis on the response mechanisms to waterlogging stress. Findings from the reviewed literature indicate that waterlogged conditions induce hypoxia in the root zone, leading to reduced photosynthetic rates, impaired nutrient uptake, and increased production of reactive oxygen species (ROS), which trigger cellular damage. These effects result in reduced plant growth and yield. Nevertheless, plants exhibit various adaptive mechanisms, such as aerenchyma formation, adventitious root development, and proline accumulation, which enhance tolerance to stress. Variations in tolerance levels among cereal species also influence the extent of yield reduction. Overall, improving plant tolerance to waterlogging stress requires an integrated approach through physiological understanding, genetic improvement, and the application of appropriate agronomic management.

Negative regulators that mitigate abiotic stress sensitivity of rice: insights and future perspectives

Deciphering abiotic stress resilience in crop plants through multiomics insights and CRISPR Cas9 mediated genome editing

Abiotic factors, such as drought, salt, severe temperatures, and heavy metal toxicity, persistently threaten global agricultural production, contributing to an estimated 40–70% of yield losses in primary food crops globally. Drought diminishes yields by as much as 50% in rice, 42% in soybean, 40% in maize, 21% in wheat, and 27–40% in chickpea, while soil salinity, impacting almost 20% of irrigated agricultural area, induces similar productivity declines. In a similar vein, temperature extremes and heavy metal toxicity worsen oxidative stress, hinder nutrient uptake, and upset cellular homeostasis, all of which impede plant growth and development. Genomics and proteomics profiling have enabled the systematic identification and functional characterization of stress-responsive genes (e.g., OsPYL9, AtWRKY8) and regulatory proteins, including heat shock protein 70 (HSP70) and glutathione transferase, which mediate stress perception and downstream adaptive signaling cascades. CRISPR-based genome editing provides a precise and promising approach for developing climate-resilient crops by targeting key gene (cytokinins oxidase gene (OsCKX2)) involved in abiotic stress tolerance, offering potential for sustainable crop improvement under changing environmental conditions.This study assesses the state of CRISPR/Cas9-based genome editing for stress tolerance, highlights the molecular and regulatory underpinnings of abiotic variables in agricultural plants. Additionally, it is expected that advancements in genome editing technologies (such as CRISPR-Cas9) and high-resolution proteomic methods would provide new options for precision agricultural trait alteration, enhancing breeding programs and aiding global efforts to assure food security. Plant survival is impacted by cellular alterations brought on by abiotic stress. Proteomics and genomics are dynamic fields of study that examine genes and proteins involved in stress tolerance. Identification of genes involved in combating abiotic stress and the understanding of their functions aid scientists in developing varieties that are resistant to various types of stress.

Crop Resilience to Combined Drought and Salinity Stress in Drylands: From Soil Processes to Genomic Solutions.

A unified framework that merges mechanistic discovery, microbiome-assisted breeding, soil and water management and systems-level predictive modelling is proposed, essential for developing climate-resilient crops to sustain dryland agriculture.