ROS and MAPK Cascades in the Post-harvest Senescence of Horticultural Products

Plants are naturally sessile and cannot move away from adverse environmental conditions. Environmental stress may induce loss of membrane integrity, which is a seminal feature of premature senescence. Therefore, plants must respond in other ways to protect themselves from abiotic and biotic stresses that involve protein kinases, which are crucial to signal transduction pathways. Protein kinases are involved in the phosphorylation of serine/threonine and tyrosine side chains of proteins. Among these protein kinases, mitogen-activated protein kinase (MAPK) cascade genes are key components of signal transduction pathways that help transduce extracellular signals to intracellular responses in animals, plants, and fungi. Interestingly, reactive oxygen species (ROS) are important and common messengers that are produced in various biotic and abiotic stresses; ROS are known to activate many of the MAPKs. In this review, we highlight the mechanisms of crosstalk between ROS and MAPK cascades in the post-harvest senescence of horticultural products and summarize recent findings about MAPK regulation and functioning in various cellular processes.