Submitted to: Letters in Applied Microbiology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/1/2008
Publication Date: 4/15/2008
Citation: Chang, P. 2008. A highly efficient gene-targeting system for aspergillus parasiticus. Letters in Applied Microbiology. 46:587-592. Interpretive Summary: Aspergillus parasiticus produces carcinogenic aflatoxins. Much of aflatoxin biosynthesis research has been carried out in this economically important plant pathogen. Aspergillus flavus is closely related to A. parasiticus and both share about 98-99 percent identity at the nucleotide level. The commonly obtained low gene targeting frequency (1-10 percent) is a challenge to studying functions of the large numbers of genes in A. flavus EST and whole genome databases, the majority of which encode hypothetical proteins. To facilitate functional genomics, a highly efficient gene targeting method was developed. The system uses an A. parasiticus recipient strain of which the ku70 gene responsible for nonhomologous integration was deleted. This results in an increase in the gene targeting frequency to higher than 90 percent. Knowledge on aflatoxin biosynthesis and fungus-plant interaction acquired from using this gene-targeting system would help to control aflatoxin contamination of crops.
Technical Abstract: Gene targeting via homologous recombination is often used to elucidate gene function. For filamentous fungi, the majority of transforming DNA integrates ectopically. Deletion of Aspergillus parasiticus ku70, a gene of the non-homologous end-joining pathway, drastically increased the gene targeting frequency.