Safeguarding genome integrity under heat stress in plants

Abstract

Heat stress adversely affects an array of molecular and cellular events in plant cells, such as denaturation of protein and lipid molecules and malformation of cellular membranes and cytoskeleton networks. Genome organization and DNA integrity are also disturbed under heat stress and, accordingly, plants have evolved sophisticated adaptive mechanisms that either protect their genomes from deleterious heat-induced damage or stimulate genome restoration responses. In particular, it is emerging that DNA damage responses are a critical defense process that underlies the acquisition of thermotolerance in plants, during which molecular players constituting the DNA repair machinery are rapidly activated. In recent years, thermotolerance genes that mediate the maintenance of genome integrity or trigger DNA repair responses have been functionally characterized in various plant species. Furthermore, accumulating evidence supports that genome integrity is safeguarded through multiple layers of thermoinduced protection routes in plant cells, including transcriptome adjustment, orchestration of RNA metabolism, protein homeostasis, and chromatin reorganization. In this review, we summarize topical progress and research trends in understanding how plants cope with heat stress to secure genome intactness. We focus on molecular regulatory mechanisms by which plant genomes are secured against the DNA-damaging effects of heat stress and DNA damage is effectively repaired. We also explore the practical interface between heat stress response and securing genome integrity in view of developing biotechnological ways of improving thermotolerance in crop species under global climate change, a worldwide ecological concern in agriculture.