Nitric oxide: a key driver of signaling in plants

Abstract

The colorless gaseous compound nitric oxide (NO) is a lipophilic free radical that diffuses readily through the plasma membrane. These attributes make nitric oxide ideal for a transient paracrine (between adjacent cells) and autocrine (within a single cell) signaling molecule. The half–life of NO in biological tissues is estimated to be < 6 Sec. This short half–life reflects the highly reactive nature of NO. It reacts directly with metal complexes and other radicals and indirectly as a reactive nitrogen oxide species with DNA, protein, and lipids. NO was first described in 1772 as nitrous air by Joseph Priestly the English theologian chemist and by co–educators. He was also the first to describe nitrous oxide (N2O), which he named nitrous air diminished. Priestly’ nitrous air induced a sensation of mild drunkenness, often coupled with bouts of uncontrollable laughter.