A plausible mechanism, based upon SHORT-ROOT movement, for regulating the number of cortex cell layers in roots

Abstract

Significance In nature, nearly all plants have only a single layer of endodermis. The number of cortex cell layers often varies between species and between roots on the same plant. Here we show that the expression of conserved SHORT-ROOT (SHR) protein, in the context of the root of Arabidopsis thaliana, is responsible for determining the number of cortex cell layers and that the number of cell layers is a function of the extent of SHR movement. These results provide a plausible model for regulating the number of cortex cell layers in plant roots that relies upon controlled intercellular movement of the SHR transcription factor.