Core mechanism of root growth identified

Plant root systems continuously explore their surrounding environments while searching for nutrients and water in the soil. The exploratory behaviour results from the ability of the growing root tips to change their growth direction as guided by environmental cues. Changes of growth direction are controlled by rapid alterations in the levels of the plant hormone auxin within the root tip.

HFSP Long-Term Fellow Ari Pekka Mähönen and colleagues
authored on Mon, 22 December 2014

How roots maintain a stable organogenesis while the same root tissue bends towards a new environmental cue has remained unknown. We demonstrate that gradients of PLETHORA transcription factors which drive root organogenesis are stable towards rapid fluctuations of auxin levels. Even though auxin regulates PLETHORA expression, the regulation is indirect and requires high levels of auxin, making the PLETHORA expression immune to auxin fluctuations.

For the full story see the press release from the Univesity of Helsinki

Reference

PLETHORA gradient formation mechanism separates auxin responses. Ari Pekka Mähönen, Kirsten ten Tusscher, Riccardo Siligato, Ondřej Smetana, Sara Díaz-Triviño, Jarkko Salojärvi, Guy Wachsman, Kalika Prasad, Renze Heidstra & Ben Scheres.Nature (2014) doi:10.1038/nature13663.

Pubmed link