Effect of Plant Preservative Mixture TM on Endophytic Bacteria Eradication from In Vitro-Grown Apple Shoots.

Endophytic contaminants are a common problem for the in vitro propagation of woody plants and have significant economic repercussions for the conservation of plant genetic resources and commercial micropropagation. In this study, first, the microbial contamination that appeared around the base of in vitro-grown apple shoots was identified as Bacillus megaterium . Then, plant preservative mixture (PPM TM ) was used as a bactericidal agent in plant tissue culture. Its efficacy for eradicating endophytic B. megaterium in in vitro cultures of apple was tested. In vitro-contaminated shoots were grown in tissue culture medium supplemented with 0.2% v / v PPM TM for 12 weeks and then transferred to medium without any PPM TM and cultured for 24 weeks. This study showed that PPM TM is an effective agent for controlling the growth of B. megaterium . Our results highlight the species-specific response of apple shoots to PPM TM . PPM TM was effective in controlling endogenous microbial contaminations from apple varieties 'Golden Delicious', 'Landsberger Renette', 'Suislepper', and 'Aport krovavo-krasnyi'; meanwhile, in 'KG 7' and 'Gold Rush', all the plants grown in the absence of PPM TM were still bacterially contaminated, even though they were pre-treated for 12 weeks in PPM TM -supplemented medium. These results therefore suggest the essentiality of further testing of extended incubation of PPM TM in these cultivars that had outbreaks of bacterial contamination.