Calcium and nitric oxide signaling in plant cadmium stress tolerance: A cross talk
Iqbal R. Mir, Harsha Gautam, Naser A. Anjum, Asim Masood, Nafees A. Khan
Abstract
Despite its known phytotoxicity, cadmium (Cd) is being added in most arable soils via different agricultural activities. Additionally, information is meager on the Cd-phytotoxicity mitigation strategies employing sustainable approaches. Essential plant nutrient calcium (Ca2+) and signaling molecule nitric oxide (NO) are known as the key regulators of plant biochemical and physiological processes under stress conditions. Though there exists a close functional synergism between Ca2+ and NO in plant stress tolerance, the role of either Ca2+ and/or NO has been explored in plant stress tolerance in isolated reports. Given this, in addition to briefly overviewing the availability, uptake, transport and toxicity (including impact on morpho-physiological traits, photosynthesis, oxidative stress, and genotoxicity), this paper aimed to highlight the general roles, transport, and signaling of Ca2+ and/or NO in plants, and appraises the literature available on their significance in improvements of plant growth, photosynthesis and control of oxidative stress under Cd stress. Effort was also made to present a crosstalk on Ca2+ and NO signaling, and the significance of its outcome in plant Cd-tolerance.