Chapter 14 - Current approaches in horticultural crops to mitigate the effect of cold stress

Abstract

Cold stress is a significant threat that causes great loss to crop yields. Various responses to cold temperature in plants include low germination rate, stunted seedlings growth, chlorosis, wilting in plants, and necrotic tissues. Reproductive growth of plants is also affected by cold and chilling temperature. Cold stress severely affects plant-cell membrane by rupturing it and damaging the cell of plant. The reason for such damage is the high level of dehydration that occurs due to freezing conditions during cold stress. The receptors that are present on the cell membrane initially recognize the cold stress and initiate the signal transduction that directs to switch on cold response–related genes as well as transcription factors. These genes and transcription factors mediate the stress tolerance in plants against cold. Crop-improvement program in horticulture is based on understanding the physiological mechanisms that are directly involved in imparting tolerance against cold stress and about the networking of genes and transcription factors responsible for signaling the cold stress. Freezing tolerance efficiently develops in temperate region horticulture plants when they are subjected to very low temperatures (nonfreezing). Exclusive changes in the pattern of metabolism and gene expression impart tolerance in plants against a freezing condition or cold stress. Recent developments and availability of a complete profile of transcripts along with mutation studies and transgenic studies in horticultural crops have given a direction to investigate the network of transcription factors that operates during cold stress. Cold stress leads to alter the expression of several important genes that ultimately increase the production of secondary metabolites, which protect the plant cells from cold stress–related damage. The significant role of cellular level metabolic signaling process, RNA splicing its export, and unwinding of the secondary structure in plants has been explained by molecular genetic analysis that regulates the expression pattern of cold stress–related genes and leads to freezing and chilling tolerance. To minimize the productivity loss of horticulture crops, it is essential to understand the physiological, biochemical, and molecular mechanisms that plants have evolved to survive under freezing or extremely cold conditions.