MLO-Mediated Ca2+ Influx Regulates Root Hair Tip Growth in Arabidopsis

This study explores the role of MLO proteins, particularly MLO15, in regulating calcium (Ca²⁺) influx during root hair tip growth in Arabidopsis. MLO15 is expressed in growing root hairs and is crucial for their elongation by modulating cytoplasmic calcium oscillations. The study shows that expressing a constitutively active MLO channel, faNTA, in fer mutants restores normal calcium oscillations, root hair integrity, and elongation, as well as reactive oxygen species (ROS) levels to wild-type conditions. The research involved analyzing root hairs from various lines, with sample sizes ranging from 99 to 148 root hairs per group. The findings suggest that MLO15 and faNTA are essential for maintaining root hair polarity and growth by regulating Ca²⁺ dynamics and ROS production, highlighting a new function for MLO proteins in plant cell growth.