PILS-dependent adaptive control of the root system architecture in Arabidopsis thaliana

• Applicant: Professor Dr. Jürgen Kleine-Vehn
• Subject Area: Plant Cell and Developmental Biology
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 470007283

Understanding how the environment modulates development is a key challenge, both from a fundamental and translational point of view. The phytohormone auxin is a key regulator of plant development and integrates internal and external signals. We have previously shown that PILS intracellular auxin transport facilitators determine auxin responses and appear to have fundamental roles in adaptive plant growth (Barbez et al., 2012; Beziat et al., 2017). Notably, brassinosteroid signalling defines nucelar auxin responses in a PILS-dependent manner (Sun et al., 2020) and this auxin/brassinosteroid cross-talk mechanism contributes to high temperature responses in roots (Feraru et al., 2019; Sun et al., 2020). Our computational modelling suggested that PILS proteins could define temporal auxin signalling dynamics, by integrating brassinosteroid with nuclear auxin signalling (Sun et al., 2020). Here we propose that PILS proteins indeed define auxin response oscillation in the basal meristem and thereby define lateral root branching. We will further define the mechanistic role of PILS proteins in periodic, auxin-dependent de novo organogenesis, using lateral root primordia development in Arabidopsis as a model. Considering that auxin and brassinosteroid (BR) jointly define the root growth rate of lateral root primordia development by a largely unknown mechanism (Bao et al., 2004), we will assess whether PILS proteins are involved in this coordinated interaction. Finally, we will assess whether the PILS-dependent crosstalk of auxin and BR signalling allows for plant adaptational responses, such as ambient temperature dependent control of lateral rooting.Accordingly, our upcoming work will fill the knowledge gap between the interplay of auxin and brassinosteroid during de novo organogenesis (Bao et al., 2004) and the oscillatory role of auxin in the basal meristem (Moreno-Risueno et al., 2010). The proposed work will lead to mechanistic information on de novo organogenesis in plants and will link intracellular auxin transport with the temporal and spatial oscillation of auxin signalling.

• DFG Programme: Research Grants