title: Effect of Agrobacterium strain and plasmid copy number on transformation frequency, event quality and usable event quality in an elite maize cultivar.
abstract: Improving Agrobacterium -mediated transformation frequency and event quality by increasing binary plasmid copy number and appropriate strain selection is reported in an elite maize cultivar. Agrobacterium-mediated maize transformation is a well-established method for gene testing and for introducing useful traits in a commercial biotech product pipeline. To develop a highly efficient maize transformation system, we investigated the effect of two Agrobacterium tumefaciens strains and three different binary plasmid origins of replication (ORI) on transformation frequency, vector backbone insertion, single copy event frequency (percentage of events which are single copy for all transgenes), quality event frequency (percentage of single copy events with no vector backbone insertions among all events generated; QE) and usable event quality frequency (transformation frequency times QE frequency; UE) in an elite maize cultivar PHR03. Agrobacterium strain AGL0 gave a higher transformation frequency, but a reduced QE frequency than LBA4404 due to a higher number of vector backbone insertions. Higher binary plasmid copy number positively correlated with transformation frequency and usable event recovery. The above findings can be exploited to develop high-throughput transformation protocols, improve the quality of transgenic events in maize and other plants.
authors.affiliation: DuPont Agricultural Biotechnology, DuPont-Pioneer, 8305 NW 62nd Avenue, P. O. Box 7060, Johnston, IA, 50131, USA.
authors.forename: Li
authors.initials: L
authors.lastname: Zhi
authors.forename: Susan
authors.initials: S
authors.lastname: TeRonde
authors.forename: Sandra
authors.initials: S
authors.lastname: Meyer
authors.forename: Maren L
authors.initials: ML
authors.lastname: Arling
authors.forename: James C
authors.initials: JC
authors.lastname: Register
authors.forename: Zuo-Yu
authors.initials: ZY
authors.lastname: Zhao
authors.forename: Todd J
authors.initials: TJ
authors.lastname: Jones
authors.forename: Ajith
authors.initials: A
authors.lastname: Anand
mesh_terms: D016960:Agrobacterium tumefaciens / Q000235:genetics* / Q000502:physiology; D056915:DNA Copy Number Variations; D004269:DNA, Bacterial / Q000235:genetics; D005822:Genetic Vectors; D030821:Plants, Genetically Modified; D010957:Plasmids / Q000235:genetics*; D018741:Replication Origin; D013045:Species Specificity; D014170:Transformation, Genetic; D019076:Transgenes; D003313:Zea mays / Q000235:genetics*
chemical_list: D004269:DNA, Bacterial