title: Construction of rice mini-chromosomes by telomere-mediated chromosomal truncation.
abstract: Telomere truncation has been shown to be an efficient technology for the creation of mini-chromosomes that can be used as artificial chromosome platforms for genetic engineering. Artificial chromosome-based genetic engineering is considered to be superior to the existing techniques of randomized gene integration by Agrobacterium or biolistic-mediated genetic transformation. It organizes multiple transgenes as a unique genetic linkage block for subsequent manipulations in breeding. Telomere truncation technology relies on three components: the telomere sequence that mediates chromosomal truncation, a selection marker that allows the selection of transgenic events, and a site-specific recombination system that can be used to accept future genes into the mini-chromosome by gene targeting. These elements are usually pre-assembled before transformation, a process that is both time and labor consuming. We found in this research that the three elements could be mixed to transform plant cells in a biolistic transformation, and produced efficient chromosomal truncations and mini-chromosomes in rice. This system will allow rapid construction of mini-chromosomes with a flexible selection of resistant markers, site-specific recombination systems and other desirable elements. In addition, a rice telotrisomic line was used as the starting material for chromosomal truncations. Mini-chromosomes from the truncations of both the telocentric chromosome and other chromosomes were recovered. The mini-chromosomes remained stable during 2 years of subculture. The construction of mini-chromosomes in rice, an economically important crop, will provide a platform for future artificial chromosome-based genetic engineering of rice for stacking multiple genes.
authors.affiliation: State Key Laboratory for Agrobiotechnology, Institute of Plant Molecular Biology and Agricultural Biotechnology, School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong.
authors.forename: Chunhui
authors.initials: C
authors.lastname: Xu
authors.forename: Zhukuan
authors.initials: Z
authors.lastname: Cheng
authors.forename: Weichang
authors.initials: W
authors.lastname: Yu
mesh_terms: D022201:Chromosomes, Artificial / Q000235:genetics*; D032461:Chromosomes, Plant / Q000235:genetics*; D005818:Genetic Engineering / Q000379:methods*; D012275:Oryza / Q000235:genetics*; D016615:Telomere / Q000235:genetics*; D014170:Transformation, Genetic; D019076:Transgenes