Expression of OsNHX1 gene in maize confers salt tolerance and promotes plant growth in the field

Abstract

Maize yield is severely affected by soil salinity. In an effort to engineer maize for improved salt tolerance, embryogenic calli of maize were co-bombarded with plasmids containing Oryza sativa Na + /H + antiporter gene (OsNHX1) and bar genes. For the molecular analysis of putative transgenic samples, PCR, Southern and Northern blots were carried out. The maize plants over-expressing OsNHX1 accumulated more biomass when grown in the presence of 200mM NaCl in greenhouse conditions. Higher Na + and K + content was observed in transgenic leaves than in wildtype leaves when treated with 100~200mM NaCl, while the osmotic potential and the proline content in transgenic leaves was lower than in wild-type maize. A field trial revealed that the transgenic maize plants produced higher grain yields than the wild-type plants at the vegetative growth stage. These results demonstrate that the OsNHX1 gene was successfully transferred into Zea mays, and the salt-tolerance of transgenic maize was improved by overexpression of the OsNHX1 gene.

Salt stress in maize: effects, resistance mechanisms, and management. A review

“…In root cells of maize, shifting sodium into vacuoles through the tonoplast appears a viable strategy to minimize sodium transport to developing shoots (Neubert et al 2005). Likewise, Chen et al (2007) reported that transgenic maize overexpressing the Oryza sativa sodium/hydrogen antiporter (OsNHX1) gene outperformed the wild-type maize at 200 mM NaCl and accumulated more sodium and potassium in leaves coupled with lower osmotic potential.…”

“…Transgenic maize equipped with the O. sativa sodium/hydrogen antiporter (OsNHX1) gene outperformed and outyielded the wild-type maize at 200 mM NaCl in greenhouse conditions. Leaves of transgenic maize had higher sodium and potassium contents coupled with lower osmotic potential than those of wildtype maize treated with 100-200 mM NaCl (Chen et al 2007). Bt transgenic lines of maize hybrid (YieldGard 2) almost maintained growth when subjected to 0, 50, 100, and 150 mM NaCl salt stress primarily due to higher chlorophyll contents and chlorophyll stability index at all salinity levels (Beltagi 2008).…”

“…The generated transgenic maize plants expressed the OsNHX1 from rice which accumulated high biomass in the presence of 200 mM NaCl (Chen et al 2007). …”

Transgenic Crops Targeting Ion Homeostasis Machinery: Bangladesh Perspective for Adaptation to Climate Change to Ensure Food Security

“…Similarly, transformation of rice with OsNHX1 and PgNHX1 (Pennisetum glaucum) conferred salt tolerance and transgenic plants showed higher shoot and root growth (Fukuda et al 2004, Chen et al 2007, Verma et al 2007). Transformation of wheat and maize with AtNHX1 showed tolerance to salt stress (Xue et al 2004 andYin et al 2004).…”

A chimeric vacuolar Na+/H+ antiporter gene evolved by DNA family shuffling confers increased salt tolerance in yeast

“…The ability to compartmentalize Na + is considered to be a salt adaptation not only conserved in halophytes but also in glycophytes (Hasegawa et al, 2000). To date, a large number of cDNAs encoding vacuolar Na + /H + antiporter have been isolated and increasing evidence has demonstrated that overexpressing vacuolar Na + /H + antiporter gene improved salt tolerance in various plant species (Chen et al, 2007a(Chen et al, , 2007bFukuda et al, 2011;Li et al, 2011;. All these studies indicate that an improved capacity for vacuolar Na + sequestration is vital to salinity tolerance and overexpression of vacuolar Na + /H + antiporters provides an approach that can contribute to the molecular breeding of salt-tolerant plants.…”