Stem strength represents one of the most critical agronomic traits, as it enables plants to resist lodging and bending, thereby contributing to their overall yield and quality. Various transcription factors have been shown to regulate stem strength in crops; however, the mechanisms underlying stem strength formation and regulation remain largely unexplored, particularly in ornamental plants. This study identified a group IIe WRKY transcription factor PlWRKY29 in herbaceous peony. Tobacco plants overexpressing PlWRKY29 exhibited significantly enhanced stems, expanded xylem, thickened cell walls and elevated lignin content compared to wild-type specimens. Conversely, PlWRKY29-silenced herbaceous peony demonstrated opposite characteristics. Further investigation of the regulatory mechanism revealed that PlWRKY29 bound to the promoter of PlLAC15, which encodes a monolignol polymerization gene that facilitates lignin deposition. These findings demonstrate that PlWRKY29 positively regulates lignin biosynthesis and stem strength, advancing our understanding of lignin biosynthetic regulation in plants.

Global population pressures have necessitated increased focus on protecting and developing resilient plant species that can maintain productivity despite environmental challenges. Environmental degradation, driven by climate change and anthropogenic activities, poses significant threats to global food security through various forms of physical stress. Major environmental constraints affecting agricultural yields worldwide include salinity, water scarcity, nutritional imbalances (encompassing mineral toxicity and deficiencies), and extreme temperatures. Crop yield is influenced by multiple abiotic factors, including agronomic conditions, climatic variables, and soil nutrient availability. Plants develop various survival mechanisms at molecular, cellular, and physiological levels in response to stress. Abiotic stress, whether occurring individually or in combination, significantly impacts crop growth and productivity. For instance, drought stress reduces leaf area, plant height, and overall crop development. Cold stress inhibits plant development and crop efficiency, leading to diminished productivity. Salinity stress not only induces water stress in plants but also negatively affects cytosolic metabolism, cell development, membrane function, and increases reactive oxygen species (ROS) production. Elevated CO₂ concentrations may enhance global precipitation patterns, potentially resulting in increased rainfall that can adversely affect crop development. Plants under excessive water stress exhibit reduced amylose content but increased crude protein levels. This affects both quality and quantity of crop production by inhibiting seed germination and causing growth impairment through combined effects of elevated osmotic potential and ion toxicity. Plants have evolved various escape-avoidance and tolerance mechanisms in response to abiotic stress, including physiological adaptations and integrated cellular or molecular responses. This review paper examines the impact of abiotic stress on morpho-physiological, biochemical, and molecular activities across various crops. Additionally, it analyzes crop interactions with abiotic stress regarding response and adaptation mechanisms, providing a fundamental framework for species selection and development of stress-tolerant varieties in the future.