Exploring the role of the plant cell cycle in Agrobacterium -mediated transformation of multi-shoot cultures of Zea mays L.

摘要

Multi-shoot cultures (MSCs) of Zea mays L. are ideal explants for transformation because each callus can yield a high number of transgenic plants. The plant cell cycle may play an important role in Agrobacterium-mediated transformation and synchronized MSCs were used to test this hypothesis in corn. Hydroxyurea blocks the cell cycle at the G1/S phase interface. In corn MSCs it induced a low level of synchronization. Co-cultivation of MSCs with Agrobacteria carrying the beta-glucuronidase (GUS) gene was initiated at peaks in the G0 /G1, S and G2/M phases and GUS activity was assayed fluorometrically and histochemically. GUS activity was higher in MSCs pre-treated with hydroxyurea and was strongly correlated to the S phase. Synchronization of the MSC cell cycle prior to Agrobacterium co-cultivation and timing the initiation of co-cultivation to allow T-DNA to reach the nucleus during the S phase peak results in higher transient transformation efficiency.