Seed Priming with 24-Epibrassinolide Alters Growth and Phenylpropanoid Pathway in Flax in Response to Water Deficit

The aim of the present study was to determine the effects of seed priming with 24-Epibrassinolide (EBR) (10-8 M) on growth, biochemical, and molecular characteristics of Linum usitatissimum L. seedlings under Polyethylene Glycol (PEG) induced drought stress conditions. Imposition of flax seedlings to 6, 12, and 18% PEG declined germination rate, shoot length, root length, fresh and dry weights, and significantly increased phenolic content and PAL (Phenylalanine Ammonia Lyase) enzymatic activity while lowering flavonoid content. Application of EBR significantly increased the germination rate, shoot and root lengths, dry weight, fresh weight, and anthocyanin content whereas reduced phenolic content. At the molecular level, CHS (Chalcone Synthase) and PAL (Phenylalanine Ammonia Lyase) transcripts were upregulated under drought stress and even more expressed by application of EBR. In conclusion, EBR pre-sowing seed priming considerably alleviated damages caused by drought stress and improved growth parameters in Linum usitatissimum L. seedlings.