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Title: Two small secreted proteins from Puccinia triticina induce reduction of ß-glucoronidase transient expression in wheat isolines containing Lr9, Lr24, and Lr26

item SEGOVIA, VANESA - Kansas State University
item Bruce, Myron
item SHOUP-RUPP, JESSICA - Kansas State University
item HUANG, LI - Montana State University
item BAKKEREN, GUUS - Agri Food - Canada
item TRICK, HAROLD - Kansas State University
item Fellers, John

Submitted to: Canadian Journal of Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/27/2016
Publication Date: 3/21/2016
Publication URL:
Citation: Segovia, V., Bruce, M.A., Shoup-Rupp, J.L., Huang, L., Bakkeren, G., Trick, H.N., Fellers, J.P. 2016. Two small secreted proteins from Puccinia triticina induce reduction of ß-glucoronidase transient expression in wheat isolines containing Lr9, Lr24, and Lr26. Canadian Journal of Plant Pathology. doi:10.1080/07060661.2016.1150884.

Interpretive Summary: Wheat farmers around the world constantly face the threat of yield losses due to fungal pathogens. One of the major diseases is leaf rust caused by the fungus Puccinia triticina. Each year, there are over seventy different races of leaf rust collected from wheat fields around the world. The fungus infects the plant and injects molecules that help overcome the plant’s defenses. However, if the plant has a gene for fungal resistance, the resistance protein may recognize one of the molecules injected by the fungus and trigger a resistant reaction and in turn, kill the cell limiting the spread of the fungus. This system also puts significant selection pressure on the fungus to select for mutations in the recognized molecule so the plant can no longer recognize a fungal infection. This research describes two proteins from P. triticina that meet the criteria for fungal molecules that trigger plant resistance responses. This information may lead to better ways of developing durable resistance.

Technical Abstract: Little is known about the molecular interaction of wheat and leaf rust (Puccinia triticina Eriks). However, genomic tools are now becoming available so that the host-pathogen interaction can be understood. In this work, a cDNA library was made from haustoria isolated from P. triticina race PBJL infected leaf tissue and clones were sequenced. One hundred and eighty-eight unigenes and singletons were characterized. Most had no assigned function, however, the remainder were involved in lipid transfer, energy production and cell wall modification. Secreted peptides are believed to be the best candidates for avirulence effectors. Ten predicted secreted proteins were found in the library. Three of the secreted proteins, Pt3, Pt12, and Pt27, were used in biolistic experiments to determine whether they could induce hypersensitive cell death, which is commonly observed in incompatible rust interactions with wheat leaf rust resistance genes. When Pt3 is co-bombarded with a ß-glucoronidase (GUS)-expressing vector into wheat isolines with resistance genes Lr9 or Lr24, a significant reduction of GUS expression is observed, presumably due to hypersensitive cell death. In other co-bombardment experiments, Pt27 induced a significant reduction in GUS expression in the isoline that contained Lr26.