Getting to the root of belowground high temperature responses in plants

The environment is continually challenging plants, and in response they use various coping strategies, such as adaptation of their growth. Thermomorphogenesis is a specific growth adaptation that promotes organ growth in response to moderately high temperature. This would eventually enable plants to cool down by dissipating heat. Although well understood for shoot organs, the thermomorphogenesis response in roots has only recently received increased research attention. Accordingly, in the past few years, the hormonal responses and underlying molecular players important for root thermomorphogenesis have been revealed. Other responses triggered by high temperature in the root encompass modifications of overall root architecture and interactions with the soil environment, with consequences for the whole plant. Here, we review scientific knowledge and highlight current understanding of root responses to moderately high and extreme temperature.