Crop Biotech Update

Deletion of Smut Fungi Genes Determines Crop Protection

December 10, 2010

Scientists at the Australian National University conducted a genome-level study of two fungi Ustilago maydis and Sporisorium reilianum that infect maize, to increase understanding on how to breed more disease-resistant crop plants. Both fungi are biotrophic or feeding on living plant parts, and secrete protein effectors on maize to manipulate the host. The host's immune system reacts by forming new proteins to combat the pathogen, and the pathogen mutates as a defense.

Dr. Britta Winterberg and her team identified divergent gene clusters that code for secreted effectors in the two fungi species. Out of the 43 regions, they randomly chose six, and deleted them from the genetic code of U. maydis. Three of the deletions led to reduced virulence, one deletion increased virulence, but two deletions had no effect.

Results of this study provide additional knowledge on the mechanism of virulence of fungi and can be used in more economically important fungi, in the development of more resistant crops.

For more information, read the full text article at http://www.sciencemag.org/content/330/6010/1546.full.