Cross-talk of NO and phytohormones in the regulation of plant development

Nitric oxide (NO) is a small gaseous signaling molecule that plays an important role in plant growth and development as well as in biotic and abiotic stress responses. Accumulating evidence indicates interaction of NO with different phytohormones and other endogenous signal molecules in the regulation of developmental processes. Most of the main class of hormones was already identified as interaction partner of NO, at least in the regulation of one developmental phase. NO can affects plant growth regulators negatively and positively; their interaction may be antagonistic or synergistic. Its effect on the regulation of plant hormones depends on its concentration, developmental phases, and environmental conditions. Although involvement of NO and its interaction with other molecules during plant developmental phases is well known, NO modulated hormone homeostasis, perception, or signal transduction, and its underlying molecular mechanism in the background is poorly characterized.