Establishment of an efficient genetic transformation system: A case study of RNAi-induced silencing of the transcription factor MeGI in Diospyros oleifera Cheng seedlings

Abstract

Persimmon (Diospyros) is an important genus of temperate fruit trees that originated in East Asia. High-efficiency genetic transformation in Diospyros spp. remains challenging, limiting studies of gene function and the use of modern technology, such as gene editing, in breeding programs. In this study, we established an efficient genetic transformation method based on the infection of hypocotyls and radicles obtained from immature D. oleifera seeds. In particular, we focused on optimising methods for infection and induction of calluses and adventitious buds. RNA interference vectors targeting the transcription factor MeGI, which has been reported to have a feminising effect, were transformed into the hypocotyls and radicles of D. oleifera, producing five positively transformed seedlings. Compared with the wild-type controls, the positively transformed seedlings exhibited dwarfed adventitious buds and narrower leaves. The phenotypic characteristics of the flowers of these positively transformed seedlings will be observed at a later date; this will not only confirm the function of MeGI in Diospyros spp. but also potentially induce the development of male floral buds in gynoecious species and further promote the development of breeding methods. The proposed genetic transformation protocol will be valuable for investigations into gene function and the development of persimmon breeding programs.