Association of the Stimulation of Plant Antioxidant Protection with Traits of Genome Instability

Using two genotypes of chamomile (Zhemchuzhina Lesostepi variety and its mutant), an association of the stimulation of accumulation of low molecular weight antioxidants in the pharmaceutical plant raw materials (inflorescences) with the traits of radiation-induced genome instability at the stage of plant flowering under conditions of X-ray presowing irradiation of seeds at doses of 5–15 Gy was studied. The study of rearrangements of DNA primary structure at different doses of radiation was carried out by PCR using eight ISSR and ten RAPD primers. Depending on the dose of radiation, changes in the spectra of amplicons during ISSR- RAPD-PCR were analyzed using the Jaccard similarity index. It was established that the largest rearrangement of the DNA primary structure in both genotypes, which is manifested in a decrease in the similarity with the control spectra of amplicons, is observed at radiation doses of 5–10 Gy. A trend towards the approximation of this index to the control one was revealed at the radiation dose of 15 Gy, which means an increase in the efficiency of repair processes. An association between polymorphism of DNA primary structure by ISSR and RAPD sequences in different genotypes and the nature of its rearrangement during irradiation was demonstrated. A comparison of these results with nonmonotonic dose dependences of changes in the specific content of flavonoids and phenols allows one to conclude about the stimulation of antioxidant protection at doses corresponding to the low efficiency of repair processes and, correspondingly, its decrease under conditions of the traits of restoration of the normal state of genetic material. An interpretation of the revealed phenomenon was given on the basis of known association of the effects of genome instability with an increase in the level of reactive oxygen species and general principles of antioxidant protection. The significance of the results obtained in the development of the scientific basis for the use of low doses of ionizing radiation in biotechnology (particularly, in pharmacology) is discussed.