J Appl Biomed 2:101-109, 2004 | DOI: 10.32725/jab.2004.012

Morphological and molecular changes induced in the callus culture of peanut (Arachis hypogaea L.) after γ-irradiation of ¹³⁷Cs

Elena Hlinková¹, Milan Bobák²

¹ Department of Genetics, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia

² Department of Plant Physiology, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia

Calli cultures of higher plants cultivated for a long-time in vitro conditions are characterized by higher resistance to γ-irradiation. The causes of this resistance are both genetic and epigenetic induced factors including cultivation conditions and exogenous growth regulators.
The γ-irradiation of ¹³⁷Cs with the doses D=1, 5, 10, 100 and 500 Gy applied on the partially synchronized peanut calli cultures showed that small doses D∈ Gy had a slight stimulation effect on the growth processes. Inhibition of the growth began for the dose D≥100 Gy. Dose LD₅₀ reached 250±50 Gy. Necrose was not detected but cells of calli cultures changed their color. Stimulating doses D∈ Gy of γ-irradiation decreased morphological polymorphism of cells and nuclei. Gene expression was changed in the first minutes after irradiation. The spectrum of proteins and polypeptides synthesized de novo changed depending on the doses used. Protein Hsp60 was registered only for doses D=100 and 500 Gy. Proteins connected with the apoptosis pathway (p21, p27, and p53) were synthesized in two waves, the first appeared between 24-48 hours after irradiation and the second appeared in the stationary growth phase. Changes in the content of GTP-binding proteins as well as auxin and cytokinin binding proteins are indicated by their participation in post-radiation repair mechanisms. The role of rad genes is discussed.

Keywords: peanut; γ-irradiation; gene expression; protein; growth processes; reparations

Received: June 6, 2003; Revised: February 4, 2004; Published: July 31, 2004  Show citation