Agriculture using genetically modified crops is emerging as an effective measure to counteract the
negative impact of abiotic stresses on crop production. Abiotic stresses mainly salt, drought, cold and heavy
metals are the major cause of crop failure which restrict crops to reach their full genetic potential. Salt, drought
and heavy metals exert their negative impact essentially by disrupting the ionic and osmotic equilibrium of the
cell, whereas, cold causes mechanical constraint to the membrane. Plants respond to abiotic stresses through
multifaceted molecular signaling pathways. Therefore, understanding of molecular signaling pathways and
identification of key molecules and their specific roles is important for crop improvement. Several genes
responsible for abiotic stress tolerance have been identified which code for antioxidants, enzymes that modify
lipids in the cell membrane, stress-response transcription factors, proteins that maintain ion homeostasis, heat
shock proteins, or enzymes that synthesize important stress-response compounds. Transgenic plants having some
of these genes have been produced and found to be abiotic stress tolerant. Present chapter reviews the plant
responses to abiotic stresses such as salinity, drought, cold and heavy metal stresses and tolerance mechanisms
through omics approaches.