Development and evaluation of a novel experimental system to control rosette leaf initiation in Arabidopsis

A novel experimental system was developed to control rosette leaf initiation in Arabidopsis. The system has simple constituents of a sequential culture of transgenic Arabidopsis carrying a hygromycin resistance gene driven by the promoter of a nopaline synthase gene (NOS::HPT) on a medium with or without 30 mg l−1 of hygromycin B, an antibiotic. Rosette leaf initiation of NOS::HPT seedlings was severely arrested in the presence of hygromycin B. Leaves were re-initiated in more than 80% of the NOS::HPT population when relieved from antibiotic influence. Expression profiles of leaf marker genes AtEXP10, AtmybL2, and GL2 indicate that leaf re-initiation occurred in a synchronous fashion. Moreover, application of hygromycin B resulted in enlargement of the NOS::HPT cotyledonous seedlings, which allowed us to dissect and collect a large amount of shoot apical tissue for molecular analysis. Taken together, our system provides a new opportunity to study functions of vegetative meristems in Arabidopsis during leaf development with biochemical and molecular biological techniques in addition to genetic techniques.