The auxin-nitric oxide highway: A right direction in determining the plant root system

Abstract

Nitric oxide (NO) appeared as a novel signal molecule in plants at theend of the twentieth century. Since then, new discoveries on the participation of NOin the regulation of plant biology have not stopped. One of the most yet intriguingaspects that are under strong investigation is the extension and scope of the NOinvolvement in the control of cell redox balance and hormone-regulated processes.In this chapter, we addressed both issues connecting root growth with theNO-mediated posttranslational modification S-nitrosylation on the auxin receptortransport inhibitor response 1 (TIR1) and on the antioxidant enzyme ascorbateperoxidase 1 (APX1). Auxin is probably the best studied plant hormone influencingroot growth and development. Even if the components of the signaling cascadeleading to the induction of auxin-responsive genes have been elucidated