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ARS Home » Northeast Area » Frederick, Maryland » Foreign Disease-Weed Science Research » Research » Publications at this Location » Publication #158472
Title: PROFILING DEFENSE-RELATED GENE EXPRESSION OF GLYCINE MAX CV. KOMATA INOCULATED WITH TWO DIFFERENT SOYBEAN RUST ISOLATES

Author
item Choi, Jane
item Frederick, Reid

Submitted to: Physiological and Molecular Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/11/2003
Publication Date: 6/11/2004
Citation: Choi, J.J., Frederick, R.D. 2004. Profiling defense-related gene expression of Glycine max cv. Komata inoculated with two different soybean rust isolates. Physiological and Molecular Plant Pathology. 93:S16.

Interpretive Summary: Soybeans are the most important legume grown in the United States, used for food, feed, and fuel. A devastating soybean disease, caused by the fungus Phakopsora pachyrhizi, is found worldwide except North America and Europe. Currently, there are no resistant cultivars commercially available in the U.S. In order to prepare for the arrival of the soybean rust pathogen and to develop resistant cultivars, it is crucial to understand the molecular mechanisms involved in resistance. In this study, several known plant defense-related genes were monitored from susceptible and resistant soybean rust interaction. Using two different methods, a real-time fluorescent RT-PCR and northern blot analyses, differences were observed between the resistant and susceptible interactions. Our results demonstrated that both molecular methods were comparable in detecting the genes used; however, real-time fluorescent RT-PCR is the more powerful technique with ability to detect even subtle differences. This later technique will be extremely useful in identifying, validating, and profiling the expression of potential rust resistance genes.

Technical Abstract: Soybeans are the most important legume grown in the United States, used for food, feed, and fuel. A devastating soybean disease, caused by the fungus Phakopsora pachyrhizi, is found worldwide except North America and Europe. Currently, there are no resistant cultivars commercially available in the U.S. Four single genes (Rpp1-Rpp4) have been described in Glycine max for resistance to P. pachyrhizi. The Asian cultivar, Komata, exhibits resistance to several soybean rust isolates and contains the Rpp1 gene conferring race-specific resistance to P. pachyrhizi. In order to prepare for the arrival of the soybean rust pathogen and to develop resistant cultivars, it is crucial to understand the molecular mechanisms involved in resistance. As an initial step to assess the expression patterns of known soybean defense-related genes from susceptible and resistant soybean rust interactions, a real-time fluorescent RT-PCR and northern blot analyses were used. The defense-related genes used in this study were: acidic and basic chitinases, beta 1,4-glucanase, and phenylalanine ammonia lyase. Overall, higher transcription levels of the chitinases were observed in the resistant interaction within the first 24 hours after inoculation. Real-time fluorescent RT-PCR is a powerful tool for use in plant gene expression studies where subtle increases can be detected.