Arrows point to rice minichromosomes, chromosomes are stained with DAPI, hybridized with FISH markers (red and green are different FISH markers), scar bar=5μM.
Engineered minichromosomes (artificial chromosomes) offer opportunities for better genetic engineering of crops than is possible with current plant transformation practices. They can be used as independent platforms for foreign gene expression without random integration into the normal chromosomes. Consequently, genes introduced to the minichromosomes do not mutate host genes and avoid the possibility of insertion into inactive regions of the genome. They will also allow unlimited amounts of DNA to be integrated at one site in a sequential manner. Hence, additional genes, multi-gene complexes, or even whole metabolic pathways can be added to the plant genotype.
Moreover, minichromosomes can be easily removed from a genotype by genetic crosses. Minichromosomes can be constructed through de novo assembly or engineering of existing chromosomes. Our rice minichromosomes are engineered minichromosomes, created by telomere-mediated chromosomal truncation. Engineered minichromosomes by telomere-mediated chromosomal truncation are stable because they contain natural centromeres. Rice is a main food stuff for the world, and we believe the application of this technology in rice genetic engineering will produce new varieties with multiple resistance to pathogens, high yield, improved nutrition value, good adaptation to the environment and other desirable traits. The engineered rice minichromosomes can also be used in producing pharmaceutical products, antibodies and vaccines, secondary metabolic, and biofuel.
