Early Foliar Proteome Response to Root Exposure to the Rhizobacterium WCS417.

WCS417 is a plant growth-promoting rhizobacterium that improves plant health and development. In this study, we investigate the early leaf responses of to WCS417 exposure and the possible involvement of formate dehydrogenase (FDH) in such responses. In vitro-grown seedlings expressing an FDH::GUS reporter show a significant increase in FDH promoter activity in their roots and shoots after 7 days of indirect exposure (without contact) to WCS417. After root exposure to WCS417, the leaves of FDH::GUS plants grown in the soil also show an increased FDH promoter activity in hydathodes. To elucidate early foliar responses to WCS417 as well as FDH involvement, the roots of wild-type Col and knock-out mutant plants grown in soil were exposed to WCS417, and proteins from rosette leaves were subjected to proteomic analysis. The results reveal that chloroplasts, in particular several components of the photosystems PSI and PSII, as well as members of the glutathione -transferase family, are among the early targets of the metabolic changes induced by WCS417. Taken together, the alterations in the foliar proteome, as observed in the - mutant, especially after exposure to WCS417 and involving stress-responsive genes, suggest that FDH is a node in the early events triggered by the interactions between and the rhizobacterium WCS417. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.