Genetic engineering of PPV resistance in plum rootstock 'Elita': an initial study

The present study describes an Agrobacterium-mediated transformation protocol for plum rootstock 'Elita' ((Prunus pumila L. × P. salicina Lindl.) × (P. cerasifera Ehrh.)) using leaf explants. The system enables an efficient plant regeneration with the retention of the traits of the original rootstock. The transformation experiments were conducted using a genetic construct containing the self-complementary sequences of a fragment of PPV-CP gene separated by an intron for inducing Plum pox virus (PPV) resistance through the mechanism of post-transcriptional gene silencing. Transgenic plum plants' rootstocks were produced from organogenic callus developed from leaf explants through a 6-month period culture after inoculation. PCR-analysis confirmed the transgenic status of the produced plants by amplification of the fragments of “hairpin”-PPV-CP construct and hpt gene. To our knowledge, this is the first report of a successful attempt to produce transgenic plum rootstock.