Ectopic overexpression of a mungbean vacuolar Na+/H+ antiporter gene (VrNHX1) leads to increased salinity stress tolerance in transgenic Vigna unguiculata L. Walp

Overexpression of Iris lactea tonoplast Na⁺/H⁺ antiporter gene IlNHX confers improved salt tolerance in tobacco

“…6A). The similar results are also observed in transgenic A. thaliana expressing VrNHX1 (Mishra et al 2014), and sweet potato expressing AtNHX1 (Fan et al 2015) and tomato expressing TNHXS1 (Gouiaa and Khoudi 2015). In addition to this, MDA content as indicators of lipid peroxidation assessed the oxidative stress induced by salt stress (Wu et al 2013).…”

Enhanced Growth Performance and Salinity Tolerance in Transgenic Switchgrass via Overexpressing Vacuolar Na+ (K+)/H+ Antiporter Gene (PvNHX1)

“…However, transgenic switchgrass accumulated significantly higher K + and lower Na + in all tissues compared with control plants (Figure 7), which failed to detect the significant correlation between enhanced salt tolerance and increased accumulation of Na + . The presence of lower Na + in transgenic plants overexpressing NHXs genes was also reported in rice (Islam et al, 2010), soybean (Li et al, 2010), and cowpea (Mishra et al, 2014), These resules challenged the widely accepted notion that NHXs convey salt tolerance by enhancing Na + sequestration into vacuoles, indicating a different regulatory pathways of NHXs in salt tolerance might exist. This speculation was supported by the evidence from recent reverse genetics, in which the critical role of NHXs in K + homeostasis to withstand salt shock was confirmed (Bassil et al, 2011; Barragán et al, 2012; Andrés et al, 2014).…”

“…However, previous studies in various plant species have demonstrated that overexpressing the single gene, vacuolar Na + (K + )/H + antiporter gene, is a feasible way to create transgenic plants with enhanced salt tolerance (Mishra et al, 2014; Chen et al, 2015; Zhang et al, 2015; Sahoo et al, 2016). Consistent with these studies, transgenic switchgrass overexpressing PvNHX1 exhibited better growth performance (Figure 5) and maintained an improved physiological capacity (Figures 6, Figure S4) comparing to control plants under high salinity stress.…”

“…In plants, the sequestration of Na + in vacuole had been identified as an important mechanism to salt tolerance (Apse et al, 1999). However, recent studies have found the opposite result in transgenic rice (Islam et al, 2010), soybean (Li et al, 2010), and cowpea (Mishra et al, 2014), that greater K + , rather than Na + contents were observed under salinity stress. Emerging new reverse genetics evidence has also implicated that NHXs were not indispensable for Na + uptake into vacuoles of Arabidopsis , and confirmed their main role in the regulation of K + homeostasis (Bassil et al, 2011; Barragán et al, 2012; Andrés et al, 2014).…”

“…The successful expressions of the key enzyme genes related to the NHXs were proved to be valid to enhance the capacity for salt tolerance in diverse species, such as and cowpea (Mishra et al, 2014), tobacco (Chen et al, 2015), alfalfa (Zhang et al, 2015), and mungbean (Sahoo et al, 2016). In spite of numerous work has focused on use of NHXs in salt tolerance, the mechanism underlying the enhancement of salinity tolerance by NHXs remained unclear (Sahoo et al, 2016; Wang et al, 2016).…”