Nitric oxide is essential for vesicle formation and trafficking in Arabidopsis root hair growth

Abstract

The functions of Nitric Oxide (NO) in processes associated to root hair growth in Arabidopsis were analyzed. NO is located at high concentrations in the root hair cell files at any stage of development. NO is detected inside of the vacuole in immature actively growing root hairs and later, NO is localized in cytoplasm when they become mature. Experiments performed by depleting NO in Arabidopsis root hairs indicate that NO is required for endocytosis process, vesicle formation and trafficking, and it is not involved in nucleus migration, vacuolar development and transvacuolar strands. The Arabidopsis G?4,3 mutant (double mutant nia1/nia2) is severely impaired in NO production and generates smaller root hairs than wt. Root hairs from Arabidopsis G?4,3 mutant show altered vesicular trafficking and are reminiscent of NO-depleted root hairs from Arabidopsis wt. Interestingly, normal vesicle formation and trafficking as well as root hair growth is restored by exogenous NO application in Arabidopsis G?4,3 mutant. All together, these results firmly support the essential role played by NO in Arabidopsis root hair growing process.