Plant Heat Stress Response and Thermotolerance

Climate change and global warming are considered to be major threats for agricultural production and food safety. Decreased yield of several important crops has already been related to frequently occurring extreme environmental conditions such as heat waves. Since most of the economically and dietary important crops are sensitive to high temperatures, the development of cultivars that can withstand adverse temperatures is a prerequisite for meeting the demands for increased food production. The processes of sensing and responding to heat are complex phenomena in plants which comprise the activation of numerous regulatory and signaling pathways that eventually lead to a fine metabolic adjustment to ensure cell survival. Currently, our knowledge of heat stress response is greatly advanced by the massive production of datasets derived from -omics studies which supplement the current models with new genes, proteins, and metabolites or even introduce whole new pathways. This information is essential for the improvement of plant thermotolerance either through breeding programs or approaches using genetic engineering. This chapter contains an assembly of several aspects regarding heat stress response and thermotolerance. The effects of high temperatures on major aspects of plant growth and development are described, and different methods for thermotolerance screening are presented. In addition, putative heat sensing mechanisms are discussed and the most important metabolic changes are elaborated. Last, a summary of efforts and strategies to improve thermotolerance by breeding or genetic engineering is given.