Identification and study of changes in expression pattern of some genes involved in drought tolerance in Lentil (Lens culinaris)

The research was conducted to study changes in expression pattern of some genes involved in drought tolerance due to the problem of terminal drought stress in rainfed lentil agriculture in Iran.

In order to identify the consensus sequence of the coding sequence (CDS) of selected lentil genes; Aquaporin PIP2, Fructose bisphosphate aldolase, Oxygen-evolving enhancer protein2, WRKY1 and Xyloglucan endotransglucosylase/hydrolase, expressed sequence tag (EST) and reads were identified through similar ortholog sequences in other leguminosae plants. 90, 60 and 30 percent of field capacity were considered as control, medium and severe stress respectively. RNA was extracted from both control and severe drought stress treated plants leaf samples, cDNA was synthesized from RNA samples. Expression profiles of the genes, were determined via real time PCR technique. To represent the effect of drought stress on lentil plant, some morphological, physiological and biochemical characteristics were measured.

Characteristics like plant height, shoot fresh weight, root fresh weight, shoot dry weight, root dry weight, relative water content, leaf area index, chlorophyll and protein content decreased due to drought stress, leaf trichome density, electrolyte leakage index, proline and carbohydrate content, malondialdehyde and hydrogen peroxide increased in drought stress. Analysis of real time PCR demonstrated expression of AQUAPIP2، FBA and WRKY1 genes were increased and expression of XTH and OEE2 genes were decreased under severe drought stress condition.

The results show that AQUAPIP2, FBA and WRKY1 genes are involved in drought tolerance. Due to higher expression of AQUAPIP2 and WRKY1 genes in the tolerant genotype, reduction of RWC in this genotype is less. Less increase in hydrogen peroxide in the tolerant genotype, partly influenced by higher expression of AquaPIP2 gene and higher activity of antioxidant enzymes, which was influenced by higher expression of AquaPIP2 gene in tolerant genotype than susceptible genotype. The increase in carbohydrate content in both genotypes was partially affected by FBA gene expression.