The 30th International Conference on Arabidopsis Research (ICAR 2019)

667 / 2019-04-30 14:58:23

Root hair is an idea system to study tip growth mechanism. In the past two decades, key factors have been identified to regulate different growth stages of root hair. In this study, we carried out a c

root hairs, chemical genetics, tip growth, membrane order

Plenary track > Cell Biology

Root hair is an idea system to study tip growth mechanism. In the past two decades, key factors have been identified to regulate different growth stages of root hair. In this study, we carried out a chemical genetics screen, aiming to identify novel modulators of root hair growth. After three rounds of screening from a 2000 compound library, we found one chemical which specifically promoted root hair growth without affecting other developmental processes. The compound was designated as RHP1 (ROOT HAIR PROMOTER 1). RHP1 facilitated root hair growth by almost 3 folds at nanomolar concentration. We further proved that RHP1 did not interfere with cell fate, initiation or planar polarity but specifically enhanced tip growth. We also showed that the major regulators of root hair tip growth, including the ROP signaling, cytoskeleton organization and phosphoinositide distribution, were not changed after RHP1 treatment. However, RHP1 treatment altered the concentration of sterol and the plant specific sphingolipid GIPC. As the result of the change of lipid profile, we also observed increased lipid order in both root hair tip as well as the post-Golgi vesicles underneath the tip region, indicating that lipid order could determine the post-Golgi sorting specifically for tip growth. Therefore, by using chemical genetics screening, we have uncovered a novel mechanism in the regulation of root hair tip growth, which may shed bright application perspective in the future.