The Recretohalophyte Tamarix TrSOS1 Gene Confers Enhanced Salt Tolerance to Transgenic Hairy Root Composite Cotton Seedlings Exhibiting Virus-Induced Gene Silencing of GhSOS1

Abstract

The salt overly sensitive 1 (SOS1) gene encodes the plasma membrane Na+/H+ antiporter, SOS1, that is mainly responsible for extruding Na+ from the cytoplasm and reducing the Na+ content in plants under salt stress and is considered a vital determinant in conferring salt tolerance to the plant. However, studies on the salt tolerance function of the TrSOS1 gene of recretohalophytes, such as Tamarix, are limited. In this work, the effects of salt stress on cotton seedlings transformed with tobacco-rattle-virus-based virus-induced gene silencing (VIGS) of the endogenous GhSOS1 gene, or Agrobacterium rhizogenes strain K599-mediated TrSOS1-transgenic hairy root composite cotton plants exhibiting VIGS of GhSOS1 were first investigated. Then, with Arabidopsis thaliana AtSOS1 as a reference, differences in the complementation effect of TrSOS1 or GhSOS1 in a yeast mutant were compared under salt treatment. Results showed that compared to empty-vector-transformed plants, GhSOS1-VIGS-transformed cotton plants were more sensitive to salt stress and had reduced growth, insufficient root vigor, and increased Na+ content and Na+/K+ ratio in roots, stems, and leaves. Overexpression of TrSOS1 enhanced the salt tolerance of hairy root composite cotton seedlings exhibiting GhSOS1-VIGS by maintaining higher root vigor and leaf relative water content (RWC), and lower Na+ content and Na+/K+ ratio in roots, stems, and leaves. Transformations of TrSOS1, GhSOS1, or AtSOS1 into yeast NHA1 (Na+/H+ antiporter 1) mutant reduced cellular Na+ content and Na+/K+ ratio, increased K+ level under salt stress, and had good growth complementation in saline conditions. In particular, the ability of TrSOS1 or GhSOS1 to complement the yeast mutant was better than that of AtSOS1. This may indicate that TrSOS1 is an effective substitute and confers enhanced salt tolerance to transgenic hairy root composite cotton seedlings, and even the SOS1 gene from salt-tolerant Tamarix or cotton may have higher efficiency than salt-sensitive Arabidopsis in regulating Na+ efflux, maintaining Na+ and K+ homeostasis, and therefore contributing to stronger salt tolerance.

The ThSOS3 Gene Improves the Salt Tolerance of Transgenic Tamarix hispida and Arabidopsis thaliana

“…The SOS gene plays an important role in plants, and its function has been studied in A. thaliana ( Qiu et al, 2004 ; Yang et al, 2009 ; Wang et al, 2019 ), Nicotiana tabacum ( Yue et al, 2012 ), Oryza sativa ( El Mahi et al, 2019 ), Gossypium raimondii ( Che et al, 2019 ), Lycopersicon esculentum ( Olias et al, 2009 ), Zea mays ( Zörb et al, 2005 ), and P. trichocarpa ( Tang et al, 2010 ; Zhou et al, 2014 ). However, few studies have investigated the salt tolerance function of ThSOS in T. hispida .…”

Comparative metabolomic profiling in the roots of salt-tolerant and salt-intolerant maize cultivars treated with NaCl stress

“…Salt stress often induces oxidative damage, impaires membrane integrity, and causes apoptosis (Che et al 2019, Zhang et al 2019b. NaCl stress causes dehydration of the root cells as well as it damage membranes which may lead to cell death, as it was determined by Evans staining in this study.…”

Overexpression of ThSOS from Tamarix hispida improves salt tolerance

“…The SOS gene plays a significant role in plants. SOS gene function has been studied in Arabidopsis thaliana [30][31][32], Nicotiana tabacum [33], Oryza sativa [1], Gossypium raimondii [34], Lycopersicon esculentum [35], Zea mays [36], P. trichocarpa [19,37] and other plants, especially Arabidopsis [38].…”