A Small Cysteine-Rich Protein from the Asian Soybean Rust Fungus, Phakopsora pachyrhizi, Suppresses Plant Immunity

Baum, Thomas; Link, Tobias; Whitham, Steven; Hirschburger, Daniela; Pudake, Ramesh; Pedley, Kerry; Braun, Edward; Voegele, Ralf; Whitham, Steven

A Small Cysteine-Rich Protein from the Asian Soybean Rust Fungus, Phakopsora pachyrhizi, Suppresses Plant Immunity

File

2016_Baum_SmallCysteine.PDF (14.61 MB)

Date

2016-09-27

Authors

Baum, Thomas

Link, Tobias

Whitham, Steven

Hirschburger, Daniela

Pudake, Ramesh

Pedley, Kerry

Braun, Edward

Voegele, Ralf

Baum, Thomas

Whitham, Steven

Authors

Person

Baum, Thomas

Distinguished Professor

Person

Whitham, Steven

Assistant Professor

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.

Department

Plant Pathology and MicrobiologyPlant Biology

Abstract

The Asian soybean rust fungus, Phakopsora pachyrhizi, is an obligate biotrophic pathogen causing severe soybean disease epidemics. Molecular mechanisms by which P. pachyrhizi and other rust fungi interact with their host plants are poorly understood. The genomes of all rust fungi encode many small, secreted cysteine-rich proteins (SSCRP). While these proteins are thought to function within the host, their roles are completely unknown. Here, we present the characterization of P. pachyrhizi effector candidate 23 (PpEC23), a SSCRP that we show to suppress plant immunity. Furthermore, we show that PpEC23 interacts with soybean transcription factor GmSPL12l and that soybean plants in which GmSPL12l is silenced have constitutively active immunity, thereby identifying GmSPL12l as a negative regulator of soybean defenses. Collectively, our data present evidence for a virulence function of a rust SSCRP and suggest that PpEC23 is able to suppress soybean immune responses and physically interact with soybean transcription factor GmSPL12l, a negative immune regulator.

Comments

This article is published as Qi, Mingsheng, Tobias I. Link, Manuel Müller, Daniela Hirschburger, Ramesh N. Pudake, Kerry F. Pedley, Edward Braun, Ralf T. Voegele, Thomas J. Baum, and Steven A. Whitham. "A small cysteine-rich protein from the Asian soybean rust fungus, Phakopsora pachyrhizi, suppresses plant immunity." PLoS pathogens 12, no. 9 (2016): e1005827, doi: 10.1371/journal.ppat.1005827.