Ginseng γ-thionin is localized to cell wall-bound extracellular spaces and responsive to biotic and abiotic stresses

Genomic DNA sequence of a γ-thionin in the Panax ginseng plant, termed Pgγ-thionin, contains 2 exons coding a 225-bp open reading frame with its deduced 75 amino acid sequence interrupted by 1 internal intron. The mRNA transcript level of Pgγ-thionin was ubiquitously expressed in the leaf, flower bud, stem, root and rhizome, with its highest expression in the roots. Pgγ-thionin was responsive to both biotic and abiotic stresses, such as an 18-fold increase after exposure to ABA. Fluorescent tagged-Pgγ-thionin protein was localized to cell wall-bound extracellular spaces. Our finding indicates that Pgγ-thionin might be involved in cellular defense responses.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► We found the genomic DNA of γ-thionins from P. ginseng encodes 225 bp ORF. ► The 3-D structure of Pgγ-thionin is similar to the previously reported γ-thionin. ► Pgγ-thionin was responsive to sets of biotic and abiotic stresses. ► Pgγ-thionin was found to be localized to cell wall-bound extracellular spaces.