Responses and adaptations of plants to abiotic stress: transcriptional regulation of secondary metabolic pathways, metabolomics, and nanobiological approaches.

Plants are continuously exposed to diverse abiotic stresses such as drought, salinity, extreme temperatures, and heavy metal toxicity, each of which disrupts cellular homeostasis and reactive oxygen species (ROS) generation and impairs development. To survive under these adverse conditions, plants activate a complex network of transcriptional regulators that remodel primary and secondary metabolic pathways. These regulatory cascades, involving transcription factors such as AP2, WUSCHEL, MYB, bHLH, WRKY, and NAC, orchestrate the biosynthesis of key secondary metabolites, including phenolics, flavonoids, terpenoids, and alkaloids, that function as antioxidants, osmoprotectants, and signaling molecules. Advances in metabolomics have provided deeper insights into stress-induced metabolic reconfigurations, enabling high-resolution profiling of pathway metabolic fluxes and revealing novel metabolites associated with adaptive resilience and tolerance. Alongside engineering abiotic stress resistance, nanobiological approaches have emerged as innovative strategies to modulate and remediate transcriptional responses and secondary metabolite production. This review comprehends current understanding of transcriptional regulation of secondary metabolism under abiotic stress, integrates metabolomics-driven discoveries, and highlights the potential of metabolites and metabolomics-based tools to augment plant adaptive mechanisms. Together, these interconnected perspectives offer a comprehensive framework for developing stress-resilient crops in the era of climate change.