Reaction of transgenic plum cv. HoneySweet to the Plum pox virus after a severe infection of Monilinia sp. – short communication

Resistance to Plum pox virus (PPV) in transgenic Prunus domestica L., clone C5 (cv. HoneySweet) was evaluated in a regulated field in the Czech Republic for fifteen years (2002-2016). PPV mild symptoms appeared in C5 trees only in several leaves situated close to the point of inoculum grafting up to 2010. No symptoms of PPV were observed in the years 2011-2013 and results of ELISA and RT-PCR detection tests were negative. In the twelfth year (2013), there was a severe unusual natural attack of plum trees by Monilinia sp. This Monilinia sp. attack occurred only one time - in 2013. There was no Monilinia sp. infection in 2002-2012 and in 2014-2016. Mild PPV symptoms reappeared in several leaves of transgenic plum trees in the next two years (2014-2015) and the presence of PPV was proved by DAS-ELISA and confirmed by RT-PCR.