Development of Protoporphyrinogen Oxidase as an Efficient Selection Marker for Agrobacterium tumefaciens-Mediated Transformation of Maize

• Published in: Plant physiology (Bethesda) 2003-10, Vol.133 (2), p.736-747
• Main Authors: Xianggan Li, Sandy L. Volrath, David B. G. Nicholl, Charles E. Chilcott, Marie A. Johnson, Ward, Eric R., Marcus D. Law
• Format: Article
• Language: English
• Subjects: Adaptation to environment and cultivation conditions; Agrobacterium; Agrobacterium tumefaciens - enzymology; Agronomy. Soil science and plant productions; Arabidopsis; Arabidopsis - enzymology; Arabidopsis - genetics; Biological and medical sciences; Breeding schemes. Varia; Callus; Complementary DNA; Corn; Embryos; Fundamental and applied biological sciences. Psychology; Genetic Complementation Test; Genetic mutation; Genetics and breeding of economic plants; Genetics, Genomics, and Molecular Evolution; Herbicide resistance; Herbicides; Light; Oxidases; Oxidoreductases Acting on CH-CH Group Donors - genetics; Plant breeding: fundamental aspects and methodology; Plant Proteins - genetics; Plants; Plants, Genetically Modified - genetics; Protoporphyrinogen Oxidase; Selection, Genetic; Transformation, Genetic - radiation effects; Transgenic plants; Varietal selection. Specialized plant breeding, plant breeding aims; Zea mays; Zea mays - genetics
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.103.026245

In this article, we report the isolation of plant protoporphyrinogen oxidase (PPO) genes and the isolation of herbicidetolerant mutants. Subsequently, an Arabidopsis double mutant (Y426M + S305L) was used to develop a selectable marker system for Agrobacterium tumefaciens-mediated transformation of maize (Zea mays) and to obtain multiple events tolerant to the PPO family of herbicides. Maize transformants were produced via butafenacil selection using a flexible light regime to increase selection pressure. Butafenacil selection per se did not change transgene copy number distribution relative to other selectable marker systems, but the most tolerant events identified in the greenhouse were more likely to contain multiple copies of the introduced mutant PPO gene. To date, more than 2,500 independent transgenic maize events have been produced using butafenacil selection. The high frequency of A. tumefaciens-mediated transformation via PPO selection enabled us to obtain single-copy transgenic maize lines tolerant to field levels of butafenacil.