Rapid transporter regulation prevents substrate flow traffic jams in boron transport

Researchers at the John Innes Centre collaborated with colleagues from the University of Tokyo to understand the regulation of boron transport in Arabidopsis. Nutrient uptake relies on both a regulatory circuit within cells, and a coordinated behaviour across tissues. This work used both computational and molecular biology tools to model the effects of slowing boron uptake, discovering that this peturbation of the system leads to traffic-jam like behaviour of nutrient flow. Read more about it in this JIC news article. Experiments were partly funded through the OpenPlant Fund.

Sotta, N., Duncan, S., Tanaka, M., Takafumi, S., Marée, A.F., Fujiwara, T., Grieneisen, V.A., 2017. Rapid transporter regulation prevents substrate flow traffic jams in boron transport. eLife 2017;6: e27038.


Nutrient uptake by roots often involves substrate-dependent regulated nutrient transporters. For robust uptake, the system requires a regulatory circuit within cells and a collective, coordinated behaviour across the tissue. A paradigm for such systems is boron uptake, known for its directional transport and homeostasis, as boron is essential for plant growth but toxic at high concentrations. In Arabidopsis thaliana Boron up-take occurs via diffusion facilitators (NIPs) and exporters (BORs), each presenting distinct polarity. Intriguingly, although boron soil concentrations are homogenous and stable, both transporters manifest strikingly swift boron-dependent regulation. Through mathematical modelling, we demonstrate that slower regulation of these transporters leads to physiologically detrimental oscillatory behaviour. Cells become periodically exposed to potentially cytotoxic boron levels, and nutrient throughput to the xylem becomes hampered. We conclude that, while maintaining homeostasis, swift transporter regulation within a polarised tissue context is critical to prevent intrinsic traffic-jam like behaviour of nutrient flow.