Preventing scattering of Tetranychus urticae in Rosa hybrida through dsCOPB2 expression

Abstract

To obtain rose plants resistant to Tetranychus urticae, which is one of the major pests of roses grown in a plastic house or greenhouse to be harvested as cut-flowers, we introduced the double-stranded RNA of the coatomer protein complex (dsCOPB2) from T. urticae (inserted into the pPZP200-Bar vector) to somatic embryos or embryogenic calluses of a rose breeding line (KR056006), using an Agrobacterium-mediated transformation method. It took 11 to 41 months to obtain eight plants, which were regenerated from the somatic embryos or embryogenic calluses through a selection procedure that uses phosphinothricin acetyltransferase (ppt; 2 mg L − 1) after co-cultivation. Validation of the transgene in pseudo-transgenic plants was verified via genomic polymerase chain reaction (PCR) and Southern Blot analyses. It was confirmed that one to six copies of the transgene were transferred to the eight dsCOPB2-transgenic lines; the levels of the transgene were analyzed via real-time quantitative PCR (RT-qPCR). In the resistance test of one transgenic line (KR056006-COPB2–13) against T. urticae, the pest showed a high mortality rate of approximately (∼89%), and egg-laying was relatively decreased by approximately 88%, compared to those for a non-transgenic (NT) rose line, KR056006. This suggests that the transgenic rose plants with high accumulated amounts of dsCOPB2 have a negative effect on the survival of T. urticae. It is expected that these results will accelerate the development of pest-resistant cultivars and may replace conventional pest control methods in general.