Overexpression of tomato thioredoxin h (SlTrxh) enhances excess nitrate stress tolerance in transgenic tobacco interacting with SlPrx protein. (February 2022)

• Record Type: Journal Article
• Authors: Zhai, Jiali; Qi, Qi; Wang, Manqi; Yan, Jinping; Li, Kunzhi; Xu, Huini
• Is Part Of: Plant science. Volume 315(2022)
• Publication Date: 2022-02
• Subjects: Tomato -- Thioredoxin -- Excess nitrate -- Reactive oxygen species; Botany -- Periodicals; Botanique -- Périodiques; 580
• DOI: 10.1016/j.plantsci.2021.111137
• Languages: English
• ISSNs: 0168-9452

Abstract

Highlights: Cys54 is important for SlTrxh activity. SlTrxh overexpression tobacco enhance nitrate stress tolerance. SlTrxh interacte with SlPrx. Abstract: The thioredoxin (Trx) system plays a vital function in cellular antioxidative defense. However, little is known about Trx in tomato under excess nitrate. In this study, we isolated the tomato gene encoding h-type Trx gene ( SlTrxh ). The mRNA transcript of SlTrxh in roots and leaves of tomato was induced incrementally under excess nitrate for 24 h. Subcellular localization showed that SlTrxh might localize in the cytoplasm, nucleus and plasma membrane. Enzymatic activity characterization revealed that SlTrxh protein possesses the disulfide reductase function and Cysteine (Cys) 54 is important for its activity. Overexpressing SlTrxh in tobacco resulted in increasing seed germination rate, root length and decreasing H2 O2 and O2 − accumulation, compared with the wild type (WT) tobacco under nitrate stress. While overexpressing SlTrxhC54S (Cysteine 54 mutated to Serine) in tobacco showed decreased germination rate and root length compared with the WT after nitrate treatment. After nitrate stress treatment, SlTrxh overexpressing transgenic tobacco plants have lower malonaldehyde (MDA), H2 O2 contents and Reactive Oxygen Species (ROS) accumulation, and higher mRNA transcript level of NtP5CS, NtDREB2, higher ratio of ASA/DHA and GSH/GSSG, higher activities of ascorbate peroxidase and NADP thioredoxin reductase. Besides, SlTrxh overexpressing plants showed higher tolerance to Methyl Viologen (MV) in the seed germination and seedling stage. The yeast two-hybrid, pull-down, Co-immunoprecipitation and Bimolecular luciferase complementation assay confirmed that SlTrxh physically interacted with tomato peroxiredoxin (SlPrx). These results suggest that SlTrxh contributes to maintaining ROS homeostasis under excess nitrate stress interacting with SlPrx and Cys54 is important for its enzyme activity.