Scanning electron microscopy picture of a soybean leaf infected by the rust fungus Phakopsora pachyrhizi. The leaf and the fungus were artificially painted in green and in orange, respectively. The section shows invading infection hyphae of the fungus inside the leaf mesophyll, whereas the spores are visible below the leaf breaking through the lower epidermis (Picture by U. Steffens, Bayer Crop Science).

Fungicide field trial plots close to Dourados (Mato Grosso do Sul, Brazil). Untreated control plot in the foreground, with soybean plants showing a high level of infestation with Phakopsora pachyrhizi (Picture by S. Lamprecht, Bayer Division Crop Science).

Phakopsora pachyrhizi is responsible for the Asian Soybean Rust (ASR) disease and is the major pathogen of soybean. It causes severe losses in almost all soybean-growing areas. Nearly 300 billion tons of the legume are produced annually, and used primarily as feedstock and for bioenergy production. Yield damage caused by ASR can be dramatic (reported cases from 60 percent in the US, to total losses in tropical regions). Today, the use of fungicides is the main way to control this disease. So far, breeding approaches to identify durable and race-independent disease resistant germplasm were unsuccessful. In order to sustainably protect soybean against rust disease in the future, a range of different strategies can be foreseen like chemical or biological product application or plant modification by breeding or trait approaches. In all cases, a better knowledge of the biology of P. pachyrhizi could clearly foster disease management programs.

JGI will host the genome sequences of three P. pachyrhizi isolates (K8108, MT2006 & UFV02). All three are available at the PhyloGroup page - https://mycocosm.jgi.doe.gov/Phakopsora