Agrobacterium-mediated transformation of a Dendrobium orchid with the class 1 knox gene DOH1

Abstract.

Transgenic orchid (Dendrobium Madame Thong-In) plants were regenerated by inoculating thin-section explants from protocorm-like bodies (PLBs) with Agrobacterium tumefaciens strain LBA4404 harboring a binary vector that carried the orchid DOH1 antisense gene. The transformation was performed through two consecutive stages of cocultivation, with the first stage occurring on antibiotic-free medium for 3 days and the subsequent stage on medium containing 50 mg/l carbenicillin for 3–4 weeks. Proliferated PLBs were repeatedly selected for kanamycin resistance. The presence and expression of the transgene were assessed by molecular analyses. Expression of the DOH1 antisense gene caused abnormal multiple shoot development, indicating a role for DOH1 in the basic plant architecture in orchid.