Effect of salt stress on the genes expression of the vacuolar H+ -pyrophosphatase and Na+/H+  antiporter in Rubia tinctorum

Salinity which covers vast areas of the world is increasing every year. But some plants like madder can grow in these areas. Madder (Rubia tinctorum) is a perennial plant species from the Rubiaceae family. In this study, madder plants were first treated by different concentration of NaCl (100, 200, 300, and 400 mM). Then gene expression of salinity stress was studied. For gene study, vacuolar H+-pyrophosphatase pump (AVP) and tonoplast Na+/H+ antiporters (NHX) from madder plant were isolated and sequenced. Analyzing protein sequences of these genes demonstrated that the protein sequences have high similarity with the same genes in other plants. Constructing phylogenetic trees based on the protein sequences of the AVP and NHX genes, we found high similarity with Coffea arabica and Capsicum annuum, respectively. Studying gene expression of the AVP and NHX under the condition of salt stress revealed that the genes were up-regulated, which continues up to 400 mM of salt concentration.