title: Importance of nitric oxide in cadmium stress tolerance in crop plants.
abstract: Cadmium (Cd(2+)) is a widespread heavy metal pollutant in the environment with a long biological half-life, originating mainly from industrial processes and phosphate fertilizers. It is easily taken up by plants, resulting in toxicity symptoms, such as chlorosis, wilting, growth reduction, and cell death. This cellular toxicity might result from interactions with vital metabolic pathways, carboxyl or thiol groups of proteins and reactive oxygen species (ROS) burst in plants. Plant exposure even to low concentrations of Cd may lead to cell death but the mechanism of its toxicity is still debatable. Therefore, exploring various ways to improve crop productivity and/or alleviate Cd stress effects is one of the major areas of concern. Nitric oxide (NO) is a hydrophobic gaseous molecule involved in various physiological processes such as germination, root growth, stomatal closure, control of the flowering timing etc. NO also functions as cell signaling molecule in plants and play important roles in the regulation of plant responses to both abiotic and biotic stress conditions. At the molecular level, NO signaling includes protein modification by binding to critical cysteine residues, heme or iron-sulfur centers and tyrosine residue nitration via peroxynitrite formation (ONOO(-)), mobilization of secondary messengers (Ca(2+), cyclic GMP and cyclic ADP-Rib) and modulation of protein kinase activities. Significant research had been done to understand the NO biosynthesis and signaling in plants under stress, but several questions still need to be answered. The present review is focused specifically on the importance of NO as Cd stress modulator in crop plants.
authors: Stress Physiology and Molecular Biology Lab, Centre for Biotechnology, Faculty of Life Sciences, MD University, Rohtak 124 001, India. ssgill14@yahoo.co.in
authors: Sarvajeet Singh
authors: SS
authors: Gill
authors: Mirza
authors: M
authors: Hasanuzzaman
authors: Kamrun
authors: K
authors: Nahar
authors: Anca
authors: A
authors: Macovei
authors: Narendra
authors: N
authors: Tuteja
mesh_terms: D002104:Cadmium / Q000633:toxicity*; D008954:Models, Biological; D009569:Nitric Oxide / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects*; D010944:Plants / Q000187:drug effects* / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D017382:Reactive Oxygen Species; D002104:Cadmium; D009569:Nitric Oxide