THERMO-ROOT - A mechanistic analysis of root thermomorphogenesis in Arabidopsis thaliana

• Applicant: Professor Dr. Marcel Quint
• Subject Area: Plant Physiology ; Plant Cell and Developmental Biology
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 520299173

Thermomorphogenesis describes the effect of ambient temperature on plant morphogenesis. Moderately elevated temperatures tend to stimulate growth across species and tissues. While thermomorphogenesis in above-ground shoot tissues is meanwhile fairly well understood on the physiological and the mechanistic level, root thermomorphogenesis lacks a comprehensive understanding. From an ecophysiological perspective, shoot thermomorphogenesis enhances evaporative leaf cooling which enable plants to keep photosynthetic activity within a reasonable endogenous temperature range, also in elevated ambient temperatures. Thermomorphogenic promotion of root growth may go hand in hand with drought responses and enable the plant to reach deeper soil layers with presumably better water access faster. Our preliminary data show that roots are able to sense temperature changes independent of the shoot. In contrast to the shoot, growth promotion is not achieved by temperature-induced activation of cell elongation but rather by increasing cell proliferation. We have evidence suggesting that auxin relays temperature information to the cell cycle, which increases cell division rates at elevated temperature, resulting in the production of more root cells and thereby promotion of primary root growth. In this proposal we suggest to investigate in mechanistic detail how auxin increases cell proliferation at high temperatures. This includes a) the generation of a single cell RNA-seq data set of root tips of 20°C vs. 28°C grown seedlings, b) cell biological dissection of auxin fluxes and the behavior of the polar auxin transport machinery in response to temperature changes, and c) identification of thermosensitive components that regulate entry of meristematic cells into the cell cycle. Together, this project may enable a mechanistic understanding of root thermomorphogenesis signaling downstream of a yet unknown root temperature sensor.

• DFG Programme: Research Grants