The potential of selenium to induce salt stress tolerance in Brassica rapa: Evaluation of biochemical, physiological and molecular phenomenon

Abstract

The efficacy of selenium (Se) to ameliorate salinity stress in Brassica rapa was elucidated using an in-vitro and in-silico hybrid approach. Selenium was applied as a seed priming agent on the seeds grown in salt-spiked soils. The priming treatment facilitated all the growth indicators and physiological parameters, including chlorophyll synthesis, sugar contents, gas exchange attributes, etc. The advantageous effects of Se were accredited to the alleviation of salinity stress through reducing the malondialdehyde (MDA), proline, electrolyte leakage, and hydrogen peroxide (H2O2) level. Similarly, modulations in the expression of genes encoding antioxidative enzymes enhanced reactive oxygen species (ROS) scavenging capacity along with a decrease in sodium (Na+) ions, reciprocally enhancing potassium (K+) ions and resulting in a higher K+/Na+ ratio. Additionally, based on in silico studies, a significant difference in the surface overlap of the stress-responsive proteins, including DREB, SOS3, and STXBP1 of B. rapa, was observed, indicating the involvement of Se in the foiling interaction of NaCl with the enzymes. In the case of the CAT macromolecule, ligands NaCl exhibited a -1.9-fold lower docking score as compared to sodium selenite -4.9-fold, indicating a more overlapped interactive surface than sodium chloride. The binding energies analysis recorded -3.3 kcal/mol of binding energy for the best pose of sodium selenite in the case of DREB, while it was -3.5 and -3.5 kcal.mol-1 for SOS3 and 1 STXBP1, respectively. Ligand analysis revealed a frequent existence of hydrogen bonds besides the hydrophobic interactions, salt bridges, and pi–pi interactions representing high structural and functional stability. Results of the current study unveiled an in-vitro and in-silico hybrid bioinformatics system to unveil the biochemical, physiological and molecular phenomenon behind selenium-driven salt resilience in B. rapa.