A modified method of total RNA isolation and quantitative analysis of superoxide dismutase gene expression from different organs of Ipomoea carnea

Ipomoea carnea (I. carnea) has unique biological features for the study of cellular and molecular adaptation mechanisms due to presence of diverse alkaloid and its cadmium tolerance capacity. The present study was directed to quantify total SOD content in different organs of the plant and further extended to relative quantification of cytosolic CuZn-SOD, Fe-SOD and Mn-SOD mRNA. A modified method of total RNA isolation from the plant I. carnea which is rich in alkaloids has been described. Total SOD content of apical and lateral bud was highest, but transcript abundance of cytosolic CuZn-SOD was much lower as compared to root and leaves. In these cases Mn- and Fe-SOD mRNA was relatively higher and perhaps that was contributing to the high SOD activity. However, less photosynthetically active organs like root and petal show less SOD activity but mRNA level of cytosolic CuZn-SOD was competitive in these cases. The results showed that SODs in different compartments are differently regulated and each SOD isoenzyme must be performing specific function related to its cellular localization and expression of the protein isoforms depend upon local accumulation of superoxide

Superoxide dismutase-mentor of abiotic stress tolerance in crop plants

Abiotic stresses impact growth, development, and productivity, and significantly limit the global agricultural productivity mainly by impairing cellular physiology/biochemistry via elevating reactive oxygen species (ROS) generation. If not metabolized, ROS (such as O2 •−, OH•, H2O2, or 1O2) exceeds the status of antioxidants and cause damage to DNA, proteins, lipids, and other macromolecules, and finally cellular metabolism arrest. Plants are endowed with a family of enzymes called superoxide dismutases (SODs) that protects cells against potential consequences caused by cytotoxic O2 •− by catalyzing its conversion to O2 and H2O2. Hence, SODs constitute the first line of defense against abiotic stress-accrued enhanced ROS and its reaction products. In the light of recent reports, the present effort: (a) overviews abiotic stresses, ROS, and their metabolism; (b) introduces and discusses SODs and their types, significance, and appraises abiotic stressmediated modulation in plants; (c) analyzes major reports available on genetic engineering of SODs in plants; and finally, (d) highlights major aspects so far least studied in the current context. Literature appraised herein reflects clear information paucity in context with the molecular/genetic insights into the major functions (and underlying mechanisms) performed by SODs, and also with the regulation of SODs by post-translational modifications. If the previous aspects are considered in the future works, the outcome can be significant in sustainably improving plant abiotic stress tolerance and efficiently managing agricultural challenges under changing climatic conditions