Lawrence Berkeley National Laboratory

Soybean rust is caused by two closely related fungal pathogens, Phakopsora pachyrhizi and P. meibomiae. The Asian soybean rust pathogen P. pachyrhizi (ASR) is highly aggressive and is responsible for significant losses of soybean crop in Africa, Asia, Australia and South America (Figure 1). It was discovered for the first time in the continental United States in Louisiana in November 2004. During 2005, the presence of ASR was confirmed in 138 counties across nine southern states. ASR poses a significant threat to the U.S. soybean industry (17 billion dollar anually), depending on the severity and extent of subsequent outbreaks. Currently, no commercial soybeans are resistant to ASR, and fungicides are generally recognized as the most effective means for controlling the disease. Very little is known about the molecular mechanisms involved in the soybean-rust interaction. In order to develop new strategies to control the disease, it is crucial to increase our understanding of the biology of the pathogen and the infection process. Here, we present strategies and preliminary results from the P. pachyrhizi Genome Sequencing Project, including the complete mitochondrial genome sequence and the comparative analysis of expressed sequence tags (ESTs) generated from four specific-stages of P. pachyrhizi.