Cloning and comparative modeling identifies a highly stress tolerant Cu/Zn cytosolic super oxide dismutase 2 from a drought tolerant maize inbred line

PeerJ. 2023 Mar 13:11:e14845. doi: 10.7717/peerj.14845. eCollection 2023.

Abstract

Plants have a complex system of stress response that deals with different types of stresses. Maize (Zea mays L.), one of the most important crops grown throughout the world, across a range of agro-ecological environments, employs complex mechanisms of gene regulation in response to drought stress. HKI 335 is a tropical maize inbred line showing remarkable adaptation to drought stress. Abiotic stresses, like drought, trigger the production of reactive oxygen species (ROS) due to the incomplete reduction or excitation of molecular oxygen, eventually leading to cell damage. Superoxide dismutase (SOD, EC 1.15.1.1) is a metalloenzyme that acts as the first line of defense against ROS. We cloned the Sod2 gene from HKI 335 inbred line and analyzed its protein through detailed in silico characterization. Our comparative modeling revealed that at the level of tertiary structure, the HKI 335 SOD2 protein is highly similar to Potentilla atrosanguinea SOD2, which had been previously identified as highly thermostable SOD that can tolerate autoclaving as well as sub-zero temperatures. We performed phylogenetic analysis, estimated physicochemical properties, post-translational modifications, protein-protein interactions, and domain composition of this SOD2. The phylogenetic analysis showed that orthologous sequences of SOD from different species were clustered into two clusters. Secondary structure prediction indicates that SOD2 is a soluble protein and no transmembrane domains have been found. Most of the beta sheets have RSA value greater than 2. The Ramachandran plot from PDBsum revealed that most of the residues fall in the highly favored region. It was estimated that the value of the instability index was less than 40, the value of the aliphatic index was extremely high and the GRAVY value lies between -2 and +2. We could identify only one phosphorylation site, located at position 20 with a score of 0.692. Overall, the unique stress-tolerant properties of the HKI 335 SOD2, may be one of the reasons contributing to the high drought tolerance trait exhibited by HKI 335 maize inbred line. Further research may reveal more insights into the drought adaptation mechanism in maize and the eventual deployment of the trait in maize hybrids.

Keywords: Bioinformatic analysis; Drought stress; SOD2; Superoxide dismutase; Zea mays L..

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cloning, Molecular
  • Droughts*
  • Oxides / metabolism
  • Phylogeny
  • Reactive Oxygen Species / metabolism
  • Seedlings / genetics
  • Superoxide Dismutase / genetics
  • Superoxide Dismutase-1 / genetics
  • Zea mays* / genetics
  • Zinc / metabolism

Substances

  • Reactive Oxygen Species
  • Superoxide Dismutase-1
  • Superoxide Dismutase
  • Oxides
  • Zinc

Grants and funding

This work was supported by a research grant from the National Agricultural Science Fund of Indian Council of Agricultural Research (ICAR) (NASF/GTR-5004/2015-16/204) to Pranjal Yadava and Tanushri Kaul. Fatima Nazish Khan is supported by the Junior Research Fellowship from Core Research Grant project of the Science and Engineering Research Board (CRG/2019/005451) to Pranjal Yadava. Anuradha Gautam was supported by a Senior Research Fellowship from ICAR (NPTC 3015). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.