Nuclear Proteomics to Understand the Promotive Effect of Plant-Derived Smoke Solution on Wheat Under Salt Stress

Background: Salinity, which hampers wheat growth and development, is one of the major abiotic stresses. Plant-derived smoke (PDS) solution alleviates salt stress and promotes wheat growth and development; however, the underlying molecular mechanisms have not been completely clarified. Methods: In this study, nuclear proteomics was employed to reveal the promotive effect of PDS solution on salt-stressed wheat. Nuclear fractions were isolated from wheat roots, and their purity was confirmed via enrichment of histone H3 and reduction of cytosolic ascorbate peroxidase. Using this nuclear purification technique, label-free nano LC–MS/MS-based nuclear proteomics was performed to identify differentially abundant nuclear proteins in salt-stressed wheat with or without PDS solution treatment. Results: Salt stress decreased histone H2A and DNA polymerase levels, whereas PDS solution treatment of salt-stressed wheat increased levels of histone variants (H2A, H2B, H3, and H4), DNA polymerase, and DNA topoisomerase II. In addition, the PDS solution increased the levels of pre-mRNA cleavage factor Im 25 kDa subunit and RNA helicase in salt-stressed wheat. Immunoblot analysis further validated the increase in histone deacetylase levels triggered by the PDS solution treatment in the salt-stressed wheat. Conclusions: These results suggest that PDS solution alters nuclear proteins in a way that contributes to chromatin remodeling and transcription during salt stress.