Genetic and molecular mechanisms underlying root architecture and function under heat stress-A hidden story

Heat stress events are resulting in a significant negative impact on global food production. The dynamics of cellular, molecular and physiological homoeostasis in aboveground parts under heat stress are extensively deciphered. However, root responses to higher soil/air temperature or stress signalling from shoot to root are limited. Therefore, this review presents a holistic view of root physio-morphological and molecular responses to adapt under hotter environments. Heat stress reprogrammes root cellular machinery, including crosstalk between genes, phytohormones, reactive oxygen species (ROS) and antioxidants. Spatio-temporal regulation and long-distance transport of phytohormones, such as auxin, cytokinin and abscisic acid (ABA) determine the root growth and development under heat stress. ABA cardinally integrates a signalling pathway involving heat shock factors, heat shock proteins and ROS to govern heat stress responses. Additionally, epigenetic modifications by transposable elements, DNA methylation and acetylation also regulate root growth under heat stress. Exogenous application of chemical compounds or biological agents such as ascorbic acid, metal ion chelators, fungi and bacteria can alleviate heat stress-induced reduction in root biomass. Future research should focus on the systemic effect of heat stress from shoot to root with more detailed investigations to decipher the molecular cues underlying the roots architecture and function.

Automated summary

Heat stress has a significant negative impact on global food production, but limited research has been done on root responses to this stress. The review discusses the physiological, morphological, and molecular responses of roots to heat stress, including the interaction between genes, phytohormones, reactive oxygen species, and antioxidants. The regulation and transport of phytohormones, as well as epigenetic modifications, play important roles in root growth under heat stress. Furthermore, exogenous application of chemical compounds or biological agents can alleviate the reduction in root biomass caused by heat stress. Future research should focus on understanding the systemic effect of heat stress from shoot to root and unraveling the molecular cues underlying root architecture and function.