Phloem-specific overexpression of AtOPT6 in Arabidopsis enhances Zn transport into shoots. (August 2019)

• Record Type: Journal Article
• Authors: Wongkaew, Arunee; Nakamura, Shin-ichi; Sekimoto, Hitoshi; Yokoyama, Tadashi; Ohkama-Ohtsu, Naoko
• Is Part Of: Plant science. Volume 285(2019)
• Page Start: 91
• Page End: 98
• Publication Date: 2019-08
• Subjects: GCS γ-glutamylcysteine synthetase -- GS glutathione synthetase -- OPT oligopeptide transporter -- pSUC2 promoter of sucrose-proton symporter 2 -- Zn Zinc; Arabidopsis thaliana -- Glutathione -- Oligopeptide transporter -- Phloem -- Shoot Zn content -- Zn; Botany -- Periodicals; Botanique -- Périodiques; 580
• DOI: 10.1016/j.plantsci.2019.04.022
• Languages: English
• ISSNs: 0168-9452

Abstract

Highlights: Overexpression of AtOPT6 in phloem tissues affected Zn behaviors in Arabidopsis. AtOPT6 -overexpressing lines showed increased foliar glutathione contents. Enhanced GSH transport in phloem tissues increased Zn translocation into shoots. Abstract: The Arabidopsis oligopeptide transporter AtOPT6 is membrane transport protein that mediated transport of glutathione in both the reduced (GSH) and oxidized (GSSG) forms. In this study, the role of AtOPT6 in glutathione distribution throughout the plant was investigated. We found that transgenic Arabidopsis overexpressing AtOPT6 under the control of a phloem-specific promoter of sucrose-proton symporter 2 ( pSUC2 ), remarkably increased AtOPT6 transcript levels, ranging from 30- to 40-fold in shoots and 6- to 10-fold in roots, relative to the wild type. AtOPT6 -overexpressing lines could elevate the foliar glutathione content; however, glutathione content in the phloem did not change. We observed that the ratio of shoot glutathione content to total glutathione content increased in AtOPT6 -overexpressing lines, but not in transgenic Arabidopsis with elevated foliar GSH synthesis. These results indicate the possibility that loading and unloading of glutathione in phloem tissues are enhanced in AtOPT6 -overexpressing lines under the control of pSUC2 . The results of heavy metal analysis revealed that transgenic Arabidopsis overexpressing AtOPT6 under the control of pSUC2 could promote the transport of Zn into shoots as effectively as transgenic Arabidopsis with elevated foliar GSH synthesis, or wild-type plants with exogenous foliar application of GSH.