Aim of study: Non expressor of
pathogenesis related gene (NPR1) is a key regulator of the SA dependent
systemic acquired resistance (SAR) in plants. Although NPR1 is a well
known important regulator of salicylic acid to biotic stress,
researching on abiotic stress have not yet been well founded.
Materials and methods: With this aim, soybean (Glycine max L.) SA88 plants were grown with Hoagland solution for two weeks. Seedlings were treated with 200 mM NaCl, 10 % PEG 6000 and 200 mM NaCl + 10 % PEG 6000 and harvested at 2h, 4h, 6h (short term) and 7 day and 14 day (long term) of treatment.
Main results: The results showed that plants treated with NaCl showed a better defense response in physiological parameters than PEG. Additionally, PEG stress lead to more oxidative damage at long term, while combined stress at short term in soybean leaves. Otherwise, the highest accumulation of ABA, SA and proline level was with PEG treatment at both short term and long term of treatment. However, GmNPR1 gene expressions were upregulated with PEG stress significantly at 7 day and combined stress at 14 day.
Discussion: Considering the short term effects on GmNPR1 transcript levels, combined stress were more pronounced compared to NaCl and PEG stress alone.
Research highligts: Consequently, this work firstly determined that osmotic stress may role as a potential signal but not salt stress for the regulation of NPR1 in soybean leaves.