Overexpression of a vacuolar H+-pyrophosphatase and a B subunit of H+-ATPase cloned from the halophyte Halostachys caspica improves salt tolerance in Arabidopsis thaliana

Abstract

To avoid the effects of Na ? toxicity, plants have developed mechanisms to sequester Na ? in vacuoles. This sequestration process is catalyzed by a vacuolar Na ? /H ? antiporter, with the transmembrane electrochemical potential initially established by the tonoplast H ? -ATPase and H ? -pyrophosphatase (H ? -PPase). In this study, we cloned HcVP1 and HcVHA-B encoding a vacuolar H ? -PPase and a B subunit of H ? -ATPase, respectively, from Halostachys caspica, a succulent shrub that is highly salt-tolerant and widely distributed in Central Asia. The cDNA of HcVP1 is 2,295 bp and contains an open reading frame (ORF) of 764 amino acids and the HcVHA-B cDNA is 1,467 bp with an ORF of 488 amino acids. Semi-quantitative PCR revealed that transcription of both genes in H. caspica is induced by salt stress. Additionally, increased seed germination and improved plant growth were observed in transgenic Arabidopsis thaliana plants heterologously expressing HcVP1 or HcVHA-B, relative to wild-type plants when grown in the presence of NaCl. Specifically, Na ? content in leaves of transgenic Arabidopsis plants was higher than in wild-type leaves. These results demonstrate that overexpression of a vacuolar H ? -PPase and a B subunit of H ? -ATPase from H. caspica may enhance salt tolerance in transgenic Arabidopsis through increased accumulation of Na ? in vacuoles.

Expression of wheat Na+/H+ antiporter TNHXS1 and H+- pyrophosphatase TVP1 genes in tobacco from a bicistronic transcriptional unit improves salt tolerance

“…Activation of the V-ATPase could further contribute to the enhanced stress tolerance of line TP3cl38. Indeed, many studies have demonstrated that the enhancement of V-ATPase activity contributes to the improvement of salt stress tolerance in plants (Kluge et al 2003;Padmanaban et al 2004;Guo et al 2006;Batelli et al 2007;Wang et al 2011;Zhou et al 2011;Hu et al 2012). Thus, transgenic TP3 plants, which over-expressed simultaneously TNHXS1 and TVP1 genes, exhibited the best salinity tolerance compared to control plants when challenged with salt treatment in vitro or under greenhouse conditions.…”

Salt-tolerant genes from halophytes are potential key players of salt tolerance in glycophytes

“…Halostachys caspica Arabidopsis Transgenic plants showed increased seed germination and improved growth in presence of NaCl. More Na + was accumulated in the leaves of transgenic plants Hu et al (2012) 34 SaVHAc1 Spartina alterniflora Rice SaVHAc1 improved salt tolerance and also up regulated genes involved in cation transport and ABA signaling Baisakh et al (2012) 35…”

“…The expression levels of HcVP1 and HcVHA-B transcripts were low in the absence of NaCl and significantly high with increasing salt concentrations up to 500 mM NaCl. The overexpression of the genes HcVP1 and HcVHA-B in Arabidopsis improved salt tolerance through the increased accumulation of Na + in vacuoles (Hu et al, 2012). Recently Chen et al (2015b) reported that the improved salttolerant ability in salt-sensitive yeast strain and also in Arabidopsis by inserting the Zoysia matrella vacuolar pyrophosphatase (ZmVP1).…”

Co-expression of vacuolar Na+/H+ antiporter and H+-pyrophosphatase with an IRES-mediated dicistronic vector improves salinity tolerance and enhances potassium biofortification of tomato

“…Similarly, the over-expression of AtVP1 or its homologs in transgenic plants resulted in both drought and salt tolerance (Gaxiola et al, 2001). Interestingly, the co-expression of an NHX gene and an H + -PPiase or a V-H + ATPase resulted in a better salinity tolerance than that imparted by the single expression of an NHX gene Hu et al, 2012). Based on sequence similarity and subcellular localization, the plant NHX proteins can be divided into two classes, class I and class II (Pardo et al, 2006;Rodriguez-Rosales et al, 2009;Leidi et al, 2010).…”