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.

No abstract

Gamma (γ)-irradiation of plants at low doses can provoke a broad range of growth-stimulating effects. In order to reveal universal target genes that are involved in molecular pathways of radiation hormesis establishment, we studied nine barley cultivars for their tolerance to γ-irradiation of seeds. Four morphological traits were assessed in barley seedlings after γ-irradiation of seeds at 20 Gy. Nine cultivars were sorted according to the sensitivity to irradiation as γ-stimulated, “no morphological effect”, or γ-inhibited. Gene expression of 17 candidate genes was evaluated for the 7 most contrasting cultivars. Changes in expression of barley homologues of PM19L and CML31 were suggested as possible determinants of radiation hormesis effect. The possible role of jasmonate signaling in roots in radiation growth stimulations was revealed. Morphological analysis and gene expression study showed that the genetic background of a cultivar plays an important role in eustress responses to low-dose γ-irradiation of seeds.

No abstract