ARS scientists have invented a method for identifying, detecting, and discriminating between the two fungal pathogens that cause the disease soybean rust. The scientists designed a polymerase chain reaction (PCR) test that specifically amplifies DNA differences between the Phakopsora pachyrhizi (P. pachyrhizi), the Asian type pathogen and Phakopsora meibomiae (P. meibomiae), the New World type pathogen. It is important to distinguish between the two pathogens, because the Asian type is more aggressive than the New World type. Also, the recent spread of the Asian type to Africa and South America makes this disease an immediate threat to U.S. soybean production. Soybean rust is a devastating disease of soybean plants that infects plant tissue. Yield losses are due to severe infection. Heavily infected plants have fewer pods and lighter seeds. Market yields are even less due to poor seed quality. The disease is present in China, Taiwan, Thailand, India, Australia, Puerto Rico, Brazil, Columbia and Costa Rico. In Taiwan and Thailand, soybean rust has been described as the most economically important soybean fungal disease, with yield loses of up to 80 percent. In 1994, P. pachyrhizi was discovered in Oahu, Hawaii. ARS has spearheaded research to develop U.S. soybean cultivars with soybean rust resistance as a preventive strategy should the disease enter into the U.S mainland. In addition to soybeans, P. pachyrhizi naturally infects 31 legume species in 17 different genera.
Please refer to USPN 7,097,975 (Docket #0031.01), "PCR Methods for the Identification and Detection of the Soybean Rust Pathogen, Phakopsora Pachyrhizi," which issued on August 29, 2006. Foreign rights are available.
Reid D. Frederick
Foreign Disease-Weed Science Research
Fort Detrick, Maryland 21702-5023
(301) 619-7386 / Fax: (301) 619-2880