Engineering a Decoy Substrate in Soybean to Enable Recognition of the Soybean Mosaic Virus NIa Protease

Thumbnail Image
Helm, Matthew
Qi, Mingsheng
Sarkar, Shayan
Yu, Haiyue
Innes, Roger
Major Professor
Committee Member
Journal Title
Journal ISSN
Volume Title
Whitham, Steven
Assistant Professor
Research Projects
Organizational Units
Organizational Unit
Plant Pathology and Microbiology
The Department of Plant Pathology and Microbiology and the Department of Entomology officially merged as of September 1, 2022. The new department is known as the Department of Plant Pathology, Entomology, and Microbiology (PPEM). The overall mission of the Department is to benefit society through research, teaching, and extension activities that improve pest management and prevent disease. Collectively, the Department consists of about 100 faculty, staff, and students who are engaged in research, teaching, and extension activities that are central to the mission of the College of Agriculture and Life Sciences. The Department possesses state-of-the-art research and teaching facilities in the Advanced Research and Teaching Building and in Science II. In addition, research and extension activities are performed off-campus at the Field Extension Education Laboratory, the Horticulture Station, the Agriculture Engineering/Agronomy Farm, and several Research and Demonstration Farms located around the state. Furthermore, the Department houses the Plant and Insect Diagnostic Clinic, the Iowa Soybean Research Center, the Insect Zoo, and BugGuide. Several USDA-ARS scientists are also affiliated with the Department.
Journal Issue
Is Version Of

In Arabidopsis, recognition of the AvrPphB effector protease from Pseudomonas syringae is mediated by the disease resistance (R) protein RPS5, which is activated by AvrPphB-induced cleavage of the Arabidopsis protein kinase PBS1. The recognition specificity of RPS5 can be altered by substituting the AvrPphB cleavage site within PBS1 with cleavage sequences for other proteases, including proteases from viruses. AvrPphB also activates defense responses in soybean (Glycine max), suggesting that soybean may contain an R protein analogous to RPS5. It was unknown, however, whether this response is mediated by cleavage of a soybean PBS1-like protein. Here, we show that soybean contains three PBS1 orthologs and that their products are cleaved by AvrPphB. Further, transient expression of soybean PBS1 derivatives containing a five-alanine insertion at their AvrPphB cleavage sites activated cell death in soybean protoplasts, demonstrating that soybean likely contains an AvrPphB-specific resistance protein that is activated by a conformational change in soybean PBS1 proteins. Significantly, we show that a soybean PBS1 decoy protein modified to contain a cleavage site for the soybean mosaic virus (SMV) NIa protease triggers cell death in soybean protoplasts when cleaved by this protease, indicating that the PBS1 decoy approach will work in soybean, using endogenous PBS1 genes. Lastly, we show that activation of the AvrPphB-dependent cell death response effectively inhibits systemic spread of SMV in soybean. These data also indicate that decoy engineering may be feasible in other crop plant species that recognize AvrPphB protease activity.


This article is published as Helm, Matthew, Mingsheng Qi, Shayan Sarkar, Haiyue Yu, Steven A. Whitham, and Roger W. Innes. "Engineering a decoy substrate in soybean to enable recognition of the soybean mosaic virus NIa protease." Molecular Plant-Microbe Interactions 32, no. 6 (2019): 760-769. doi:10.1094/MPMI-12-18-0324-R. Posted with permission.

Tue Jan 01 00:00:00 UTC 2019