DNA Technology

Powerful DNA Technology Applications for Fungal Pathogens

Researchers are utilizing DNA technology and rapid sequencing of whole genomes to study the biology of plant pathogenic fungi that cause some of the world’s most devastating plant diseases that pose a serious threat to global food security, biodiversity and ecosystem health.

Situation

To understand how a microbe attacks its host, researchers must understand the machinery within the cell and how it functions. Gaining this understanding has been the focus of researchers for decades. With the advent of genomics, there is an unprecedented opportunity to dissect the molecular underpinnings of microbial virulence. OARDC researchers are aiming their focus on fungal pathogens of rice, wheat, corn and other important crops. An important example is Magnaporthe oryzae, causal agent of rice blast, which is responsible $66 billion in annual losses worldwide.

Response

To demonstrate how genomics can provide insights into microbial attack upon a host, we attempted to sequence and analyze the entire genome of a plant pathogenic fungus in less than 2 months. Using OARDC's Molecular and Cellular Imaging Center, we submitted genomic DNA from 7 fungi representing 5 different species, including the rice blast fungus, Magnaporthe oryzae. After sequencing, we assembled the genomes and predicted the function of the thousands of genes identified.

The success of rapidly sequencing and assembling a genome for a relatively modest cost generated great interest from researchers worldwide. Within 8 months of the initial study, we sequenced the genomes of 14 fungi with requests to process many more. With funding from the Biotechnology and Biological Sciences Research Council (UK) and the Gates Foundation, we will work to sequence over 100 fungal isolates from Africa

Impact

While whole genome sequencing technologies have been around for a decade and many fungal genomes have been sequenced, the cost and difficulty in managing the data made it prohibitive to most researchers. Using this approach, we have been able to pinpoint the locations of genes that the fungal pathogens of plants use during associations with their hosts. Without the rapid and cost effective sequencing, this feat used to take decades to accomplish.

Our work to make a pipeline for processing and analyzing sequencing data has shown the research community the strength of this approach. The largest impact has been in accelerating the discovery of the fungal genes involved in host associations and virulence. These discoveries will eventually lead to novel control strategies for these and other pathogens and pests.

Thomas K. Mitchell, Guo-Liang Wang, Plant Pathology; Tea Meulia, OARDC Molecular and Cellular Imaging Center

Recent publication:
Hu, J., Chen, C., Peever, T., Dang, H., Lawrence, C., and T. Mitchell. 2012. Genomic characterization of the conditionally dispensable chromosome in Alternaria arborescens provides evidence for horizontal gene transfer.
BMC Genomics. 13:17 > 
http://www.biomedcentral.com/1471-2164/13/171