The Role of Plant Hormones in Fruit Response to Photooxidative and Heat Stress

Abstract

Climate change and global warming are causing extreme and unpredictable weather during the growing season. Heat waves are more frequent and extreme in many parts of the globe, causing heat stress (HS) on top of other abiotic stress such as photooxidative stress (POS) in plant tissues including the growing fruit. Defense mechanisms and acclimation are key for these tissues to survive, for which plant hormones play a pivotal role in engaging biochemical mechanisms to accomplish this. Consequently, fruit can either grow and mature normally or develop sun-related disorders such as sunscald or sunburn. Either way, sun-exposed fruit tissue has a unique phenotype involving metabolites, physiological traits, and textural characteristics. This chapter reviews some of the biochemical events in fruit under those environmental conditions, focused on the role of phytohormones as key elements in signal transduction and gene expression in response to oxidative stress derived from exposition to high light (HL) combined with heat stress (HS), which finally implies the modulation of defense mechanisms. In addition, we discuss the role of exogenous plant growth regulators as a tool to manage adverse abiotic stresses under the current and future climate change scenario.