Artificial Chromosomes in Introducing Multiple Traits to Maize

Production of transgenic maize has relied on traditional techniques, like Agrobacterium-mediated transformation, that integrate DNA fragments into host chromosomes. Although proven to be effective, traditional techniques have certain disadvantages. The process can disrupt normal gene expression, which may result to loss of important agronomic qualities. Large numbers of transgenic plants are needed to be screened in order to find those suitable for commercial use. In addition, there is a limit to the amount of DNA that can be integrated, making it difficult to add multiple genes at a time. A discovery made by a group of US researchers may hold the solutions to these disadvantages. Using “maize mini-chromosomes” (MMC) the researchers successfully introduced entire gene cassettes to maize.

The researchers showed that MMCs behave like normal chromosomes. It is structurally stable and the genes it carries are expressed and transmitted from generation to generation. Using this technology, genes of interest can be arranged in a definite order, with each gene surrounded by their promoters or inhibitors. MMCs can be used to increase the hardiness, yield and nutritional content of crops. It can also improve biofuel production as well as enable plants to make complex compounds like medicines.

The open access article published by PLoS-Genetics is available at http://genetics.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pgen.0030179&ct=1