Enhanced Level of Anthocyanin Leads to Increased Salt Tolerance in Arabidopsis PAP1-D Plants upon Sucrose Treatment

Many lines of evidence indicate that the increased activity of enzymes involved in phenolic compound biosynthesis and the subsequent accumulation of these compounds correlate with plant resistance to abiotic and biotic stresses. The production of anthocyanin pigment gene (PAP!) was previously identified using an activation tagging approach in Arabidopsis thaliana. A. thaliana PAP1-Dominant (pap1-D) mutant was generated by activation tagging. Throughout development, the pap1-D plant exhibited massive and widespread activation of genes encoding enzymes involved in phenylpropanoid natural product biosynthesis. Due to increased anthocyanin levels, pap1-D showed enhanced tolerance to salt, an important abiotic stress imposed on plants. In pap1-D plants, PAP1 transcript accumulation increased significantly in response to salt stress and abscisic acid. Enhanced anthocyanin levels induced by sucrose treatment increased the chance of survival of pap1-D and wild-type plants exposed to a high salt medium. Taken together, results of the present study indicate that genetic engineering of the flavonoid biosynthetic pathway can be used for successful improvement of plant survival in arid areas.