The Redox-Sensitive Chloroplast Trehalose-6-Phosphate Phosphatase AtTPPD Regulates Salt Stress Tolerance

作者：Julia Krasensky-Wrzaczek, Caroline Broyart, Fernando A. Rabanal, Claudia Jonak · 发表于：Antioxidants and Redox Signaling · 年份：2014 · DOI：10.1089/ars.2013.5693 · 被引用次数：119 · 研究领域：Plant nutrient uptake and metabolism、Plant Stress Responses and Tolerance、Nitrogen and Sulfur Effects on Brassica

AIMS: High salinity stress impairs plant growth and development. Trehalose metabolism has been implicated in sugar signaling, and enhanced trehalose metabolism can positively regulate abiotic stress tolerance. However, the molecular mechanism(s) of the stress-related trehalose pathway and the role of individual trehalose biosynthetic enzymes for stress tolerance remain unclear. RESULTS: Trehalose-6-phosphate phosphatase (TPP) catalyzes the final step of trehalose metabolism. Investigating the subcellular localization of the Arabidopsis thaliana TPP family members, we identified AtTPPD as a chloroplast-localized enzyme. Plants deficient in AtTPPD were hypersensitive, whereas plants overexpressing AtTPPD were more tolerant to high salinity stress. Elevated stress tolerance of AtTPPD overexpressors correlated with high starch levels and increased accumulation of soluble sugars, suggesting a role for AtTPPD in regulating sugar metabolism under salinity conditions. Biochemical analyses indicate that AtTPPD is a target of post-translational redox regulation and can be reversibly inactivated by oxidizing conditions. Two cysteine residues were identified as the redox-sensitive sites. Structural and mutation analyses suggest that the formation of an intramolecular disulfide bridge regulates AtTPPD activity. INNOVATION: The activity of different AtTPP isoforms, located in the cytosol, nucleus, and chloroplasts, can be redox regulated, suggesting that the trehalose metabolism might rela...