Effect of rolB transgene on Prunus cerasus × P. canescens and Cydonia oblonga microshoot rhizogenesis

Abstract

With the aim to improve rooting ability, the dwarfing sweet cherry hybrid rootstock (Prunus cerasus × P. canescens) and pear rootstock (Cydonia oblinga P. Mill) were transformed with the rolB gene using Agrobacterium tumefaciens mediated gene transfer. The binary vectors with rolB gene (cloned from A. rhizogenes plasmid pRiA4), driven by their own and constitutive CaMV promoter, were used for transformation. More than 400 regenerants of both rootstocks were obtained in vitro within seven months. The plant regeneration and the rooting rate of regenerants were found to the depend on the vector used for transformation. The rooting rate was highest when a construct with the rolB gene under its own promoter was used for transformation. As compared with the control (untreated plants), after co-cultivation with A. Tumefaciens the rooting rate of Cydonia regenerants in vitro increased by 6–44% and of Prunus hybrid by 8–30%. DNA (PCR) analysis of regenerants was performed to prove transformation. It was shown that among 40 PCRtested regenerants 17.5% had a stabile rolB insert in their genome. All transformants had well-formed roots characteristic of rolB transgenic plants. Keywords: genetic transformation, DNA, rootstocks, pear, cherry