Variation of Retrotransposon Movement in Callus Culture and Regenerated Shoots of Barley

Abstract

ABSTRACTIn this study, tissue-culture-induced BARE1 (BArley Retrotransposable Element-1) retrotransposon movements were investigated in barley calli and regenerated shoots, using the Inter-Retrotransposon Amplified Polymorphism (IRAP) technique. IRAP analysis was carried out on 30-, 60-, 90-day-old calli and shoots regenerated from them. Samples from calli and regenerated shoots originating from same embryo were accepted as a group. Two sample groups originating from two different embryos were analyzed. DNAs from three mature embryos were used as control samples. The IRAP analysis of the control samples showed identical IRAP profiles of 12 bands for all three mature embryos, suggesting a lack of natural polymorphism between the tested individuals. The IRAP profiles of the two analyzed groups were different from those of the control embryo. While the samples from the first group had 14 IRAP bands, those of the second group had 16. An important feature observed for the samples from both groups was that they possess homomorphic IRAP profiles within the group. The samples from the first group had four new and two missing bands when compared with the IRAP profile of the control embryos. Similarly, the samples from the second group had four novel bands when compared with the embryos' band profile. The similarity rates, calculated by Jaccard's coefficient, were found to be 62.5%, 75% and 86.6% between embryo-first-group, embryo—second-group and first-group-second-group, respectively. The obtained results indicated that the applied tissue culture conditions could efficiently induce BARE1 movements. The observed homomorphic IRAP profiles within the group of samples consisting of calli and regenerated shoots originating from the same embryo further suggests that BARE1 activation and movements possibly occur at early stages of callus initiation after in vitro cultivation of embryos. In addition, the difference of the IRAP detected polymorphism of BARE1 between the two analyzed groups indicates that similar tissue culture conditions could induce diverse rates of these BARE1 movements.