Evaluation of gene expression of transcription factors involved in salinity tolerance in Barley (Hordeum vulgare L.) advanced genotypes

Salinity stress is considered as one of the most important abiotic stresses that significantly decreased crop production in the world. The development of salt-tolerant varieties is one of the most strategies against decreasing crop performance in saline conditions. Hence, assessment of expression patterns of genes responsible for the biosynthesis pathways can be very effective in creating tolerant genotypes. The main objective of this study was to compression of expression patterns of HvSOS1, HvSOS3, HvNHX3, and HvHKT3 genes in some advanced barley genotypes under salinity stress conditions.

In the present study, the effect of salt stress on relative changes expression of HvSOS1, HvSOS3, HvNHX3, and HvHKT3 genes in the six advanced barley genotypes along with Mehr cultivar (as a check) was investigated under the control (no NaCl) and salt (200 mM NaCl) treatments. All tested genotypes were planted under controlled greenhouse conditions using a hydroponic system. After salt treatment duration, all seedling plants were subjected to sampling and the relative expression of selected genes was estimated.

Based on obtained results, there are significant differences between treatments as well as among tested genotypes. Salt treatment significantly increased expression of HvSOS1, HvSOS3, HvNHX3, and HvHKT3 genes by 14.76-, 4.65-, 4-, and 4-fold compared to the control treatment, respectively. Comparison of the expression patterns of studied genes showed that two genotypes G3 and G6 had the highest transcription rate of mentioned genes and it seems that they have an acceptable tolerance to the high levels of salinity stress. A positive association between HvHKT3 and HvSOS genes was another obtained result so that two identified genotypes indicated the highest expression of these genes under salt treatment.  

It is inferred that increasing expression of studied genes is an important part of the salt tolerance mechanism because each of them has a key role in the signaling pathway and translocation of Na ions in the plant cells. Two identified genotypes, G3 and G6, with having this potential can be appreciated candidates for future research and use as salt-tolerant cultivars.