Cross-talk between nitric oxide and hydrogen peroxide in plant responses to abiotic stresses

• Overview cross-talk between NO and H2O2 in plant stress responses.
• Discuss how NO and H2O2 interact with each other at two levels.
• Discuss cross-talk between NO and H2O2 with other signaling pathways.

Nitric oxide (NO) and hydrogen peroxide (H2O2) are two signaling molecules, which play roles in diverse organisms. In the past two decades, evidence has been accumulating to address their involvements in stress responses in plants, but how these two molecules interact with each other and how the signals are integrated in biological processes remain fragmentary and far from clear in the literature. This review brings together the knowledge obtained so far on these two molecules and their cross-talk in plant stress responses, particularly abiotic stresses including drought, salinity, extreme temperatures, UV light, and heavy metals. We tentatively discuss, in the context of abiotic stresses, how NO and H2O2 interact with each other at two levels, biosynthesis, and regulation of gene expression or protein activities. The cross-talk between NO and H2O2 with other signaling pathways in the regulation of abiotic stress responses in plants is also discussed.