Expression analysis of lipid transfer protein gene in wheat (Triticum aestivum) under drought stress

Drought stress causes changes in morphology, physiology and gene expression profile in the plants. One of the ways to respond to this stress is to change the synthesis of specific polypeptides such as LTP (Lipid transfer proteins). For this purpose, LTP expression level was investigated under three osmotic potentials of -2, -4 and -6 bar in combination with different time courses of 0, 3, 6, 10, 24, 48 and 72 h after applying stress using RT-qPCR in DN-11 and Marvdasht genotypes. Also, the soluble sugar content in both genotypes was measured by the phenol-sulfuric acid method after each stress level. Furthermore, promoter analysis of LTP was studied using bioinformatics tools. The results showed that the highest expression level of LTP in both genotypes occurred at -6 bar osmotic potential level and 48 h after stress in DN-11 and 72 h after stress in Marvdasht. There was no significant difference between 48 h and 72 h after stress in the DN-11 genotype and between 72 h and 3 h after stress in Marvdasht genotype at P-value of ≤ 0.01, but there was a significant difference among other time courses at P-value of ≤ 0.01. Besides, the soluble sugar content increased with increasing stress levels in both genotypes, so that its amount was higher than control at -6 bar stress level. The promoter analysis showed that several domains and motifs in the LTP promoter region are activated in response to drought stress and increase its expression. Therefore, it can be concluded that LTP gene can be used as a drought resistance gene in gene transformation and genetic engineering programs.