ABSTRACT
Plants are exposed to various kinds of biotic and abiotic stresses in their day-to-day life. Biotic stress majorly results from attack by bacteria, viruses, fungi, nematodes, and insects, and abiotic stresses are caused by higher salinity, temperature, metal toxicity, and drought. Under stressed situation plants’ growth and productivity decreases as the energy is siphoned toward the defense process as elucidated in earlier research work. These stresses are sensed by plants using various sensors and receptors and then the resultant stress is countered by the production of various defense compounds and enzymes through the activation of different defense pathways. Biomolecules such as phenolics, flavonoids, antioxidative metabolites, and enzymes counter the induced stress. Hormone signaling plays a key role in plant defense mechanism activation, wherein different hormones act synergistically or in opposition to one another. These are resultant of molecular activities involving different kinds of molecular entities such as downregulation or upregulation of transcription factors, reactive oxygen species, kinase cascades, and small RNA, which alter the expression of genes having a key role in stress regulation. Different biochemical and next-generation sequencing techniques ushered into the recognition of different transcription factors, small RNAs, and their regulatory role in stress tolerance. This chapter will help in understanding the molecular basis of stress tolerance in plants, which could find applications in the development of stress-tolerant varieties of crop plants with enhanced yield using genetic engineering or through selective breeding.
Keywords
Abiotic; Antioxidative Enzymes; Biotic; RNAi; Transcription Factors; Phytohormones
