Functional Characterization of the Tau Class Glutathione-S-Transferases Gene (SbGSTU) Promoter of Salicornia brachiata under Salinity and Osmotic Stress.

Vivekanand Tiwari,Amit Kumar Chaturvedi,Avinash Mishra,Bhavanath Jha,Manish Kumar Patel,Haitao Shi

doi:10.1371/journal.pone.0148494

Vivekanand Tiwari, Amit Kumar Chaturvedi + Show 4 more

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https://doi.org/10.1371/journal.pone.0148494

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Journal: PloS one	Publication Date: Feb 17, 2016
Citations: 66	License type: CC BY 4.0

Affiliation: Central Salt and Marine Chemicals Research Institute

Abstract

Reactive oxygen or nitrogen species are generated in the plant cell during the extreme stress condition, which produces toxic compounds after reacting with the organic molecules. The glutathione-S-transferase (GST) enzymes play a significant role to detoxify these toxins and help in excretion or sequestration of them. In the present study, we have cloned 1023 bp long promoter region of tau class GST from an extreme halophyte Salicornia brachiata and functionally characterized using the transgenic approach in tobacco. Computational analysis revealed the presence of abiotic stress responsive cis-elements like ABRE, MYB, MYC, GATA, GT1 etc., phytohormones, pathogen and wound responsive motifs. Three 5’-deletion constructs of 730 (GP2), 509 (GP3) and 348 bp (GP4) were made from 1023 (GP1) promoter fragment and used for tobacco transformation. The single event transgenic plants showed notable GUS reporter protein expression in the leaf tissues of control as well as treated plants. The expression level of the GUS gradually decreases from GP1 to GP4 in leaf tissues, whereas the highest level of expression was detected with the GP2 construct in root and stem under control condition. The GUS expression was found higher in leaves and stems of salinity or osmotic stress treated transgenic plants than that of the control plants, but, lower in roots. An efficient expression level of GUS in transgenic plants suggests that this promoter can be used for both constitutive as well as stress inducible expression of gene(s). And this property, make it as a potential candidate to be used as an alternative promoter for crop genetic engineering.

Highlights

Abiotic stresses are deteriorating for crop productivity as well as quality and are major challenge for sustainable agriculture
The nearest predicted TATA box on the promoter sequence starts from 172nd base pair upstream to the ATG codon (Table 1)
Out of different predicted TATA boxes on the promoter region, the motif identified at 172nd base pair upstream of the ATG was ABA, Dehydration & salinity stress responsive

Summary

Introduction

Abiotic stresses are deteriorating for crop productivity as well as quality and are major challenge for sustainable agriculture. Almost all stresses lead to the generation of secondary stressors within the plants, the reactive oxygen species (ROS) which cause oxidative damages to cellular macromolecules and organelles structures. Functional Validation of the SbGSTU Gene Promoter superoxide radical (OÁ-2), singlet oxygen (1O2), hydrogen peroxide (H2O2) and hydroxyl radical (OHÁ) [1]. These ROS molecules act as a homeostatic signal initiator in plants when accumulated at the lower concentration, but are lethal to the cells if crossed above the homeostatic level. The oxidation-reduction state of members of the ascorbate-glutathione cycle or some specific enzymes such as glutathione-S-transferases involve in the maintenance of cellular redox state and in stress acclimations [3]

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