Stability and instability processes in the calli of Fagopyrum tataricum that have different morphogenic potentials

Abstract

The morphogenic callus (MC) of Fagopyrum tataricum contains a large amount of flavonoids, especially rutin, and exhibits a high level of antioxidant activity. A non-morphogenic callus (NC) may appear on the surface of the MC after two to three years of cultivation and is then subjected to a consistently high level of oxidative stress. The elucidation of the molecular background of this instability is essential for gaining a better understanding of the somaclonal variation mechanisms in tissue cultures that have different morphogenic potentials. Thus, in this study we show that continuous oxidative stress in a NC might be connected with a rapid senescence process and as a result, in the upregulation of the genes that are connected with the telomere complexity, ethylene biosynthesis and the expression of DNA methyltransferases. Moreover, we analysed the presence of the hydroxyproline-rich glycoproteins in the calli and demonstrated the differences between the MC and NC. The LM2 antibody can be useful as a marker of the cells in the MC that are embryogenically determined, while the MAC207 antibody seems to be a positive marker of a MC as its signal was absent in the NC. This study also provides the first report on the effect of trichostatin A on the DNA methyltransferases and demethylases in a MC.