2009
Characterization of the soybean rust infection process in susceptible and resistance soybean interaction
Contributor/Checkoff:
Category:
Sustainable Production
Keywords:
GeneticsGenomics
Parent Project:
This is the first year of this project.
Lead Principal Investigator:
Steve Whitham, Iowa State University
Co-Principal Investigators:
Thomas Baum, Iowa State University
Reid Frederick, USDA-ARS-Foreign Disease Weed Science Research
+1 More
Project Code:
Contributing Organization (Checkoff):
Institution Funded:
Brief Project Summary:

The goal of this project is to acquire critical information about the Asian Soybean Rust (ASR) infection process and the accompanying responses of soybean in susceptible and resistant interactions. This information is essential to develop novel resistance against this potentially devastating fungus, since no durable resistance is currently present in U.S. commercial soybean cultivars and as previously described resistance genes have been broken in the field shortly after their release. Objectives of this research focus on providing solutions to the threat posed to soybean production by the appearance of ASR in the United States and to the improvement of disease resistance.

The research...

Unique Keywords:
#breeding & genetics
Information And Results
Project Deliverables

Final Project Results

The research team has completed the microscopic analysis of the growth of the Hawaii 94-1 and Taiwan 80-2 ASR isolates on plants carrying Rpp3. Plants containing Rpp3 are resistant to Hawaii 94-1 and susceptible to Taiwan 80-2. The samples that were collected cover a seven-day time course spanning early infection, development of lesions, and sporulation. The growth of both isolates is the same in Rpp3 plants through 48 hai. At 72 hai, there are significantly more haustoria made by the Taiwan 80-2 isolate (susceptible) when compared to the Hawaii 94-1 isolate (resistant). Haustoria are specialized cells formed in close association with soybean cells. The difference in formation of haustoria is one of the first signs that the Rpp3 resistance has become activated, and this timing suggests that something produced by the Hawaii 94-1 haustoria as they form or shortly thereafter is being recognized by the Rpp3 plant and causing disease resistance responses to be activated. This 72 hour time point coincides with the gene expression data as the point at which Rpp3-mediated defenses become strongly activated in response to the Hawaii 94-1 isolate. These defenses subsequently limit the growth of Hawaii 94-1 as compared to Taiwan 80-2. We have initiated the microscopic analyses of ASR growth and development during the Rpp4 resistance response. Preliminary analysis shows that the development of ASR and timing of resistance in Rpp4 plants is much like Rpp3 plants suggesting that they have similar mechanisms for recognizing and limiting ASR growth.

The United Soybean Research Retention policy will display final reports with the project once completed but working files will be purged after three years. And financial information after seven years. All pertinent information is in the final report or if you want more information, please contact the project lead at your state soybean organization or principal investigator listed on the project.