Confronting Heat Stress in Crops Amid Global Warming: Impacts, Defense Mechanisms, and Strategies for Enhancing Thermotolerance

Crops constantly face a range of biotic and abiotic stresses that negatively affect their growth and productivity. Among these, temperature-related stress, exacerbated by global climate change, poses a significant threat to crop production worldwide. Heat stress, in particular, leads to a cascade of detrimental effects, including impaired photosynthesis, increased respiration rates, membrane damage, protein denaturation, inhibited cell division and elongation, and reduced reproductive success, ultimately resulting in yield loss. In response, plants activate several defense mechanisms such as the biosynthesis of heat shock proteins, antioxidants, and reactive oxygen species scavengers, alongside the activation of heat stress-responsive transcription factors. Enhancing thermotolerance in crop plants is thus crucial for sustaining global food security. Key approaches include breeding, transgenic technologies, and the exogenous application of thermos-protectants. This review explores the different impacts of heat stress, plant responses, and the latest strategies to strengthen heat stress tolerance in major crop species.