Establishment of a Bivector Genetic Transformation System in Recalcitrant Maize Inbred Lines

Abstract

Maize is an important grain crop with high nutritional value. An effective transformation system is crucial for the genetic improvement of maize traits, but many important maize inbred lines remained recalcitrant to transformation. In this study, we developed a bivector transformation system that worked well in two recalcitrant maize inbred lines. This system included an induction vector (ZmBBM-ZmWUS) and an indicator vector (GFP), using microprojectile bombardment technology combined with Agrobacterium-mediated transformation. We found that the Zheng58 and Mo17 recalcitrant inbred lines could be transformed with this system. The whole transformation cycle lasted only 52 days, 38 days less than the traditional transformation cycle. Additionally, it was possible to eliminate inference of the induction vector and obtained progenies with only the target gene. Our results suggested that the bivector system was an optimization of the current maize transformation methods and could potentially be used in genetic improvement of maize inbred lines.