Co-expression of Pennisetum glaucum vacuolar Na+/H+ antiporter and Arabidopsis H+-pyrophosphatase enhances salt tolerance in transgenic tomato

Abstract

Salinity is one of the major abiotic stresses affecting plant productivity. Tomato (Solanum lycopersicum L.), an important and widespread crop in the world, is sensitive to moderate levels of salt in the soil. To generate tomato plants that can adapt to saline soil, AVP1, a vacuolar H(+)-pyrophosphatase gene from Arabidopsis thaliana, and PgNHX1, a vacuolar Na(+)/H(+) antiporter gene from Pennisetum glaucum, were co-expressed by Agrobacterium tumefaciens-mediated transformation. A sample of transformants was self-pollinated, and progeny were evaluated for salt tolerance in vitro and in vivo. It is reported here that co-expression of AVP1 and PgNHX1 confers enhanced salt tolerance to the transformed tomato compared with the AVP1 and PgNHX1 single gene transgenic plants and the wild-type. These transgenic plants grew well in the presence of 200 mM NaCl while wild-type plants exhibited chlorosis and died within 3 weeks. The transgenic line co-expressing AVP1 and PgNHX1 retained more chlorophyll and accumulated 1.4 times more proline as a response to stress than single gene transformants. Moreover, these transgenic plants accumulated a 1.5 times higher Na(+) content in their leaf tissue than the single gene transformants. The toxic effect of Na(+) accumulation in the cytosol is reduced by its sequestration into the vacuole. The physiological analysis of the transgenic lines clearly demonstrates that co-expression of AVP1 and PgNHX1 improved the osmoregulatory capacity of double transgenic lines by enhanced sequestration of ions into the vacuole by increasing the availability of protons and thus alleviating the toxic effect of Na(+).

Overexpression of a wheat Na+/H+ antiporter gene (TaNHX2) enhances tolerance to salt stress in transgenic tomato plants (Solanum lycopersicum L.)

“…(Bhaskaran and Savithramma 2011). In the present investigation, we observed a better germination rate and growth of TaNHX2-transgenic seeds compared to wild type (Fig.…”

“…Many reports have been published on the metabolic engineering of salt tolerance in tomato using various genes (Goel et al 2010(Goel et al , 2011Choi et al 2011). However, only a few reports have been published on genetic engineering of tomato using NHX proteins to improve salt stress tolerance Rodríguez-Rosales et al 2008;Bhaskaran and Savithramma 2011).…”

Tomato (Solanum lycopersicum L.) in the service of biotechnology

“…antiporter, which increase tolerance to salinity. The data presented by Bhaskaran and Savithramma (2011) and Yarra et al (2012) support the aforementioned hypothesis. Some research has indicated a significant role for vacuolar H ?…”

Variations in the growth, oil quantity and quality, and mineral nutrients of chamomile genotypes under salinity stress

“…against a concentration gradient) across plant cell membranes (plasmalemma and tonoplast) is usually coupled to the proton (H + ) electrochemical potential established by H + -translocating pumps. The vacuolar Na + /H + antiporter and H + -pyrophosphatase pump (H + -PPase) are genotype dependent and confer tolerance to salinity (Goel et al, 2010;Bhaskaran et al, 2011). Additionally, resistant crops benefit from the higher capacity of K + -Na + homeostasis.…”