Effect of Salinity Stress on Phenylpropanoid Genes Expression and Related Gene Expression in Wheat Sprout

Abstract

The effect of salinity (NaCl treatment) on the nutritive value of wheat sprouts was investigated by analyzing the expression of phenylpropanoid biosynthetic pathway genes and the levels of phenylpropanoid compounds. Treatment with various concentrations of NaCl (50, 100, and 200 mM) resulted in increased epicatechin levels but decreased accumulation of catechin hydrate, benzoic acid, and quercetin compounds in the sprouts compared with the control (0 mM). The trans-cinnamic acid, 4-hydroxybenzoic acid, ferulic acid, epicatechin, and total phenylpropanoid level in wheat sprout was the highest at 50 mM of NaCl treatment. Six-day-old wheat plantlets exposed to 50 mM NaCl for 6, 12, 24, 48, and 72 h, showed that the total phenylpropanoids accumulation was the highest at 48 h after the treatment and most of the treatments showed higher phenylpropanoid content than the control at the same time points. Although the shoot and root length and the fresh weight of wheat sprouts decreased with NaCl treatment, these results suggest that treatment of 50 mM NaCl improves the nutritional quality of wheat sprouts, due to increased phenylpropanoid concentrations.

The Role of Polyphenols in Abiotic Stress Response: The Influence of Molecular Structure

“…Several studies that focused on flavan-3-ols levels under drought stress reported reduced levels of flavan-3-ols in juvenal plants [ 110 , 111 ]; while in more mature plants, flavanol levels increased under drought stress [ 112 , 113 ]. Similarly, salt stress increased epicatechin levels, but decreased accumulation of catechin hydrate and quercetin compounds in wheat sprouts compared to the control [ 114 ]. This might be an indication of the crucial role of 4′, 5′-dihydroxy positions in flavonoid structures when dealing with salt stress.…”

Impact of Betaine Under Salinity on Accumulation of Phenolic Compounds in Safflower (Carthamus tinctorius L.) Sprouts

“…We observed that with increases in the concentration of NaCl, all growth parameters steadily decreased. Several previous studies have shown a significant reduction due to salinity in the growth of different plant species, including Fagopyrum tataricum, 10 Triticum aestivum, 31 Sesamum indicum, 32 Carthamus tinctorius, 7 Vigna radiata, 33 Cassia angustifolia, 34 pakchoi, 35 and Pisum sativum. 36 In C. tinctorius, the total flavonoid content was gradually increased by increasing the salinity concentration.…”

“…In another study, Cuong et al 31 asserted that NaCl, especially at concentrations of 50, 100, and 200 mM, enhanced the levels of epicatechin, but reduced the levels of catechin, benzoic acid, and quercetin in tartary buckwheat sprouts when compared with the control treatment without NaCl. The findings of this study coincide with those of Kim et al 10 and Cuong et al, 31 as we found that treatment with up to 200 mM NaCl enhanced the levels of accumulation of the following phenolic compounds: 4-hydroxybenzoic acid, catechin, ferulic acid, and benzoic acid, but decreased the amounts of caffeic acid, chlorogenic acid, and pcoumaric acid. Kim et al 10 reported a significant increase in the growth of tartary buckwheat sprouts after application of 0.1-1.0 mM betaine, which is supported by our current findings, whereas the addition of different concentrations of betaine, especially at 0.5 mM, enhanced the growth of sprouts of safflower.…”

“…10,31 Previously, it has been reported that with salinity an exogenous application of betaine showed a significant positive influence on plant growth and accumulation of secondary metabolites. The addition of betaine not only enhanced the growth of tartary buckwheat sprouts, 10 but increased it in wheat sprouts, 31 while shoot weight of Pokkali rice, and shoot and root weight of IR-28 rice that had been reduced under salinity stress, were enhanced with the application of exogenous betaine. 37 It is noteworthy that the application of betaine improved the stress tolerance of several crop species such as sorghum, spinach, and barley under salt and drought stress, as reported by Ashraf and Foolad.…”

“…They also reported that 50 mM NaCl treatment slightly increased a few phenolic compounds in comparison to others. In another study, Cuong et al 31 asserted that NaCl, especially at concentrations of 50, 100, and 200 mM, enhanced the levels of epicatechin, but reduced the levels of catechin, benzoic acid, and quercetin in tartary buckwheat sprouts when compared with the control treatment without NaCl. The findings of this study coincide with those of Kim et al 10 and Cuong et al, 31 as we found that treatment with up to 200 mM NaCl enhanced the levels of accumulation of the following phenolic compounds: 4-hydroxybenzoic acid, catechin, ferulic acid, and benzoic acid, but decreased the amounts of caffeic acid, chlorogenic acid, and p -coumaric acid.…”