Membrane trafficking in resistance gene-mediated defense against the barley powdery mildew fungus

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Surana, Priyanka
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Roger P. Wise
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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.
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Blumeria graminis f. sp. hordei (Bgh) is the causal agent of powdery mildew on barley. Bgh secretes over 700 proteins that may function to modify host processes for colonization. Differential expression analysis of Bgh genes encoding secreted proteins in an isogenic panel of host immune signaling mutants, including a novel mutation Rar3 (Required for Mla6 Resistance3), identified fungal membrane trafficking genes. Infection phenotyping and kinetics show that immune compromised mutants have similar fungal growth, thereby, attributing any differences observed in expression to mutation rather than development. Thus, we hypothesize that powdery mildew genes may be targeting the host membrane trafficking pathway to both internalize effector proteins and suppress plant defense signal relay. Next, to address the modulation of host membrane trafficking genes, we utilized differential expression analysis. This identified over 100 genes in all immune-compromised mutants, including ADP Ribosylation Factor 1 (ARF1) during host penetration by Bgh. ARF1 is a GTP-binding protein, involved in protein trafficking, ER-to-Golgi transport and Golgi-derived transport to the plasma membrane. Additionally, we utilized an expression Quantitative Trait Locus (eQTL) approach to focus on genes associated with Mla. This led to the discovery of 3,296 genes, including those in membrane trafficking pathways, that are directly or indirectly regulated by the Mla region (1HS). Taken together, these results corroborate the pivotal role membrane trafficking plays in R gene-mediated defense against powdery mildew.

Sun Jan 01 00:00:00 UTC 2017