Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 12/5/2017
Publication Date: N/A
Technical Abstract: Fusarium head blight (FHB), caused by the fungus Fusarium graminearum, is one of the most important diseases of wheat and barley worldwide. FHB not only reduces crop yield, but the fungus also contaminates grains with mycotoxins, which are harmful to humans and animals. A previous study demonstrated that F. graminearum secreted two a-L-arabinanases (Arb93A and Arb93B) which belong to the glycoside hydrolase 93(GH93) family. Members of the GH93 family, which include sialidases, share a six-bladed ß-propeller structure and play important roles in microbial pathogenesis. In this study, we investigate the role of Arb93B in wheat head blight. Arb93B deletion mutants were similar to the wild-type strain PH-1 in growth, morphology, and production of 15-ADON in liquid culture. FHB pathogenesis assays on wheat heads inoculated with deletion mutants of Arb93B exhibited about 50-60% less FHB disease and reduced DON contamination compared to heads inoculated with wild type PH-1. Gene expression studies revealed that expression of Arb93A was induced at 3 h post inoculation (hpi), reached its highest level at 12 hpi, and then was gradually reduced at 36 hpi and 7 d post inoculation. In contrast, the transcript of Arb93B was first detected at 36 hpi, and was reduced at 7 d post inoculation. Examination of Arb93B protein sequence indicated that it contains a chloroplast localization peptide, however, the fusion protein of GFP and predicted chloroplast peptide did not localize in the chloroplast via Agrobacterium-mediated transient expression. Further investigations are underway to determine the localization of the fusion protein.