Early response of barley embryos to low- and high-dose gamma irradiation of seeds triggers changes in the transcriptional profile and an increase in hydrogen peroxide content in seedlings

摘要

At low intensity, certain stress conditions may have a positive effect on growth and development of plants (eustress). Growth stimulation of barley plants after gamma irradiation of seeds in low doses was observed as an increase in root and shoot lengths. Hydrogen peroxide concentrations in shoots of irradiated plants were significantly higher than in control, while the opposite effect was observed in the roots. To elucidate the molecular basis of growth stimulation after gamma irradiation of barley seeds, we performed the transcriptomic analysis of barley embryos at different stages of seed germination. The transcriptomic data were correlated with morphological parameters and the hydrogen peroxide levels in irradiated and control plants. These data indicate that the growth stimulation by low-dose irradiation involves the transcriptional control of genes related to phytohormones, antioxidant system, late embryogenesis abundant proteins and cell wall components, with possible involvement of jasmonate and ABA signalling. Gamma irradiation of seeds at dose 100 Gy caused significant growth inhibition and promoted expression changes in transcripts related to cell cycle arrest, DNA damage repair and antioxidant system.