Overexpression of SbSI-1, A Nuclear Protein from Salicornia brachiata Confers Drought and Salt Stress Tolerance and Maintains Photosynthetic Efficiency in Transgenic Tobacco

Abstract

A novel Salicornia brachiata Salt Inducible (SbSI-1) gene was isolated and overexpressed in tobacco for in planta functional validation subjected to drought and salt stress. SbSI-1 is a nuclear protein. The transgenic tobacco overexpressing SbSI-1 gene exhibited better seed germination, growth performances, pigment contents, cell viability, starch accumulation, and tolerance index under drought and salt stress. Overexpression of SbSI-1 gene alleviated the build-up of reactive oxygen species (ROS) and curtailed the ROS-induced oxidative damages thus improved the physiological health of transgenic tobacco under stressed conditions. The higher activities of antioxidant enzymes, lower accumulation of ROS, higher membrane stability, relative water content, and polyphenol contents indicated the better survival of the transgenic tobacco than wild-type (WT) tobacco under stressed conditions. Transgenic tobacco had a higher net photosynthetic rate, PSII operating efficiency, and performance index under drought and salt stress. Higher accumulation of compatible solutes and K+/Na+ ratio in transgenic tobacco than WT showed the better osmotic and redox homeostasis under stressed conditions. The up-regulation of genes encoding antioxidant enzymes (NtSOD, NtAPX, and NtCAT) and transcription factors (NtDREB2 and NtAP2) in transgenic tobacco under stressed conditions showed the role of SbSI-1 in ROS alleviation and involvement of this gene in abiotic stress tolerance. Multivariate data analysis exhibited statistical distinction among growth responses, physiological health, osmotic adjustment, and photosynthetic responses of WT and transgenic tobacco under stressed conditions. The overexpression of SbSI-1 gene curtailed the ROS-induced oxidative damages and maintained the osmotic homeostasis under stress conditions thus improved physiological health and photosynthetic efficiencies of the transgenic tobacco overexpressing SbSI-1 gene.

Engineering of a novel gene from a halophyte: Potential for agriculture in degraded coastal saline soil

“…These observations also give support to our results for better seed germination. The earlier reports also demonstrated better performance of tobacco overexpressing the SbSI ‐ 2 and SbSI ‐ 1 genes under stresses (Kumari et al, ; Yadav et al, ). Longer roots help in more water absorption resulting into higher water content during osmotic stress (Singh et al, ).…”

“…Previously, we have developed transgenics using genes from S . brachiata and demonstrated their potential in mitigating abiotic stresses for alternative land uses (Jha, Joshi, Yadav, Agarwal, & Jha, ; Kumari et al, ; Singh, Yadav, Tiwari, Agarwal, & Jha, ).…”

“…This makes S. brachiata an important higher plant model for unique genetic resources, which can be further used for improvement of agricultural production through crop genetic engineering approach. Previously, we have developed transgenics using genes from S. brachiata and demonstrated their potential in mitigating abiotic stresses for alternative land uses (Jha, Joshi, Yadav, Agarwal, & Jha, 2011;Kumari et al, 2017;Singh, Yadav, Tiwari, Agarwal, & Jha, 2016).…”

Analysis of the Role of the Drought-Induced Gene DRI15 and Salinity-Induced Gene SI1 in Alternanthera philoxeroides Plasticity Using a Virus-Based Gene Silencing Tool

“…Up-to-now, there were many researches involved in salt-induced genes. For instance, Salicornia brachiata SI-1 and SI-2 genes were overexpressed in tobacco, conferring salinity tolerance ( Yadav et al, 2014 ; Kumari et al, 2017 ). A salt-responsive gene in wheat, TaDi19A , was identified to play a vital role in the plant salt-tolerance ( Li et al, 2010 ).…”

Population structure and developmental stage‐associated ecophysiological responses of Salicornia brachiata

“…There is the potential to develop S. brachiata as a model system for studies on the mechanisms of salt acclimation and for gene functional analyses (M. S. Rathore et al, ; Tai et al, ). The results of such studies would be useful for the development of salt‐tolerant crop plants (Kumari et al, ).…”