Plant roots constantly grow to provide the plant with water and minerals, while also giving it a firm anchor in the ground. Pluripotent stem cells, responsible for these functions, depend on signals from neighboring cells to avoid differentiation and remain pluripotent. These signals are generated by only a small group of slowly dividing cells in the so-called quiescent center inside the root.

An international research consortium led by Prof. Dr. Thomas Laux, a biologist from the University of Freiburg in Germany, has identified the transcription factor WUSCHEL HOMEOBOX (WOX) 5 as the signal molecule, showing that it moves through pores from the cells inside the quiescent center into the stem cells. When the signal WOX5 enters the stem cells through pores, it binds at specific DNA sequences, the promoters, of target genes and recruits an enzyme via a so-called adaptor protein. This enzyme changes the DNA's protein shell, the chromatin, causing the respective gene to be no longer effectively readable.

Professor Laux said that the results of their research will allow scientists to study how plant growth adjusts to different environmental conditions, adding that "this is a fascinating field of research in the era of climate change."

For more details, read the news release at the University of Freiburg website.

Figure: The quiescent centre in the root of the rock cress generates signals, thanks to which stem cells remain pluripotent and only certain daughter cells differentiate. Photograph by: Working Group Laux