Ricerc@Sapienza

Oryza sativa L. is a worldwide food-crop frequently growing in cadmium (Cd) polluted soils. High Cd concentrations alter plant development and, in particular, the root-system, both by affecting auxin metabolism and by triggering reactive oxygen/nitrogen species (ROS/RNS), thereby affecting rice yield. In addition, Cd2+ easily enters in the rice root cells through passive transport, reaching the grains after xylem-tophloem transfer, thus becoming a threat to food security.

Oryza sativa L. is a worldwide food-crop frequently growing in cadmium (Cd)/arsenic (As) polluted soils, with its root-system as the first target of the pollutants. Root-system development involves the establishment of optimal indole-3-acetic acid (IAA) levels, also requiring the conversion of the IAA natural precursor indole-3-butyric acid (IBA) into IAA, causing nitric oxide (NO) formation. Nitric oxide is a stress-signaling molecule. In rice, a negative interaction of Cd or As with endogenous auxin has been demonstrated, as some NO protective effects.

In plant cells, cadmium (Cd) and arsenic (As) exert toxicity mainly by inducing oxidative stress through an imbalance between the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS), and their detoxification. Nitric oxide (NO) is a RNS acting as signalling molecule coordinating plant development and stress responses, but also as oxidative stress inducer, depending on its cellular concentration.