Abstract
Phosphate is essential for plant growth and development. Root
architecture alternations induced by phosphate starvation (-Pi),
including primary root and lateral root growth, are mediated by iron
(Fe). However, whether and how Fe participates in the -Pi-induced root
hair growth (RHG) remains unclear. Here, with morphological, proteomic,
and pharmacological analysis, we investigate the impacts of Fe on RHG
under -Pi and the underlying mechanisms. We found that -Pi-induced RHG
was affected by the local Fe availability. Reduced sensitivity to Fe was
found in aux1-7, arf10arf16, and phr1 under -Pi, indicating auxin and
phosphate starvation-induced responses were required for the
Fe-triggered RHG under -Pi. Fe availability was then found to affect the
auxin distribution and expression of phosphate starvation-responsive
(PSR) genes. Proteomic analysis indicated vesicle trafficking was
affected by Fe under -Pi. With the application of brefeldin A, we found
the vesicle trafficking was affected by Fe, and root hairs displayed
reduced sensitivity to Fe, indicating the vesicle trafficking is
critical for Fe-triggered RHG under -Pi. Our data suggested that Fe is
involved in RHG under -Pi by integrating the vesicle trafficking, auxin
distribution, and PSR. It further enriches the understanding of the
interplay between phosphate and iron on RHG.