Submitted to: CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/15/2011
Publication Date: 9/19/2011
Publication URL: handle.nal.usda.gov.d2.nal.usda.gov/10113/53836
Citation: Hartman, G.L., Hill, C., Twizeyimana, M., Miles, M.R., Badnyopadhyay, R. 2011. Interaction of soybean and Phakopsora pachyrhizi, the cause of soybean rust. CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources. DOI: 10.1079/PAVSNNR20116025. Interpretive Summary: Soybean rust is a major disease limiting soybean production in many areas of the world. Although the disease is not always yield limiting, it has the potential under conditions that favor pathogen growth to cause major losses in most soybean-producing countries in the world. In this review article, the threat of this disease is and the potential of using host resistance is covered. The threat of this disease to soybean production in the Western Hemisphere began in Paraguay in 2001, where the disease was found in a limited number of soybean fields in the Parana River basin bordering Brazil. Later, in 2004, the fungus was found in the continental USA. There are approximately 150 species in 53 genera in the same legume family as soybean known to be hosts of P. pachyrhizi. Approximately 120 of the known hosts occur in North and Central America and could become important in the epidemiology of the disease, serving as a bridge or over- wintering host between soybean crops. The interaction between soybean genotypes and fungal isolates appears to follow gene-for-gene theory, with resistance genes controlling specific resistance. In addition to soybean, specific resistance has also been found in a number of perennial Glycine species. Dominant genes controlling pathotype- specific resistance to soybean rust have been identified and mapped to five regions in the soybean genome. Many of the resistance genes have become ineffective over time in different geographic areas following their deployment into soybean production. The search for more durable soybean rust resistance will include research on non-host and/or engineered resistance. This information is of interest to soybean pathologists, breeders, and other scientists that study plant resistance to pathogens and pests.
Technical Abstract: Soybean rust, caused by Phakopsora pachyrhizi H. Sydow & Sydow, is a major disease limiting soybean [Glycine max (L.) Merr.] production in many areas of the world. Yield losses of up to 80% were reported in experimental plots in Taiwan. Although the disease is not always yield limiting, it has the potential under the right conditions to cause major losses in most soybean producing countries in the world. The first detection of P. pachyrhizi in the Western Hemisphere after Hawaii was in Paraguay in February of 2001 where the disease was found on soybeans in a limited number of fields in the Parana River basin bordering Brazil. Phakopsora pachyrhizi was first reported in the continental United States in November 2004. P. pachyrhizi hosts number approximately 150 species in 53 genera of the legume family Fabaceae. Approximately 120 of the known hosts grow in North America and any one of them may play a role in the epidemiology of the disease as a bridge or over-wintering host. Studies have demonstrated that the interaction between soybean genotypes and P. pachyrhizi isolates are specific, indicating that at least in soybean, there are specific genes for resistance to given isolates of the pathogen. In addition to soybean, pathotype-specific resistance has been found in a number of perennial Glycine species. Dominant genes controlling pathotype-specific resistance to soybean rust have been identified and mapped to five loci in the soybean genome. There are known isolates of P. pachyrhizi that cause the known specific resistance genes to be ineffective. As the search for more durable soybean rust resistance continues, the future may also bring non-host and/or engineered disease resistance that also may help diminish the importance of the disease.