title: Characterization of Triticum aestivum Abscisic Acid Receptors and a Possible Role for These in Mediating Fusairum Head Blight Susceptibility in Wheat.
abstract: Abscisic acid (ABA) is a well-characterized plant hormone, known to mediate developmental aspects as well as both abiotic and biotic stress responses. Notably, the exogenous application of ABA has recently been shown to increase susceptibility to the fungal pathogen Fusarium graminearum, the causative agent of Fusarium head blight (FHB) in wheat and other cereals. However roles and mechanisms associated with ABA's modulation of pathogen responses remain enigmatic. Here the identification of putative ABA receptors from available genomic databases for Triticum aestivum (bread wheat) and Brachypodium distachyon (a model cereal) are reported. A number of these were cloned for recombinant expression and their functionality as ABA receptors confirmed by in vitro assays against protein phosphatases Type 2Cs. Ligand selectivity profiling of one of the wheat receptors (Ta_PYL2DS_FL) highlighted unique activities compared to Arabidopsis AtPYL5. Mutagenic analysis showed Ta_PYL2DS_FL amino acid D180 as being a critical contributor to this selectivity. Subsequently, a virus induced gene silencing (VIGS) approach was used to knockdown wheat Ta_PYL4AS_A (and similar) in planta, yielding plants with increased early stage resistance to FHB progression and decreased mycotoxin accumulation. Together these results confirm the existence of a family of ABA receptors in wheat and Brachypodium and present insight into factors modulating receptor function at the molecular level. That knockdown of Ta_PYL4AS_A (and similar) leads to early stage FHB resistance highlights novel targets for investigation in the future development of disease resistant crops.
authors.affiliation: Department of Biochemistry, University of Saskatchewan, 107 Wiggins Rd., Saskatoon, SK, S7N 5E5, Canada.|National Research Council of Canada, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada.
authors.forename: Cameron S
authors.initials: CS
authors.lastname: Gordon
authors.affiliation: National Research Council of Canada, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada.
authors.forename: Nandhakishore
authors.initials: N
authors.lastname: Rajagopalan
authors.affiliation: National Research Council of Canada, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada.
authors.forename: Eddy P
authors.initials: EP
authors.lastname: Risseeuw
authors.affiliation: Valent BioSciences Corporation, 870 Technology Way, Libertyville, Illinois, 60048, United States of America.
authors.forename: Marci
authors.initials: M
authors.lastname: Surpin
authors.affiliation: National Research Council of Canada, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada.
authors.forename: Fraser J
authors.initials: FJ
authors.lastname: Ball
authors.affiliation: National Research Council of Canada, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada.
authors.forename: Carla J
authors.initials: CJ
authors.lastname: Barber
authors.affiliation: National Research Council of Canada, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada.
authors.forename: Leann M
authors.initials: LM
authors.lastname: Buhrow
authors.affiliation: National Research Council of Canada, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada.
authors.forename: Shawn M
authors.initials: SM
authors.lastname: Clark
authors.affiliation: National Research Council of Canada, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada.
authors.forename: Jonathan E
authors.initials: JE
authors.lastname: Page
authors.affiliation: Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, SK, S7N 5E2, Canada.
authors.forename: Chris D
authors.initials: CD
authors.lastname: Todd
authors.affiliation: National Research Council of Canada, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada.|Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK, S7N 5C9, Canada.
authors.forename: Suzanne R
authors.initials: SR
authors.lastname: Abrams
authors.affiliation: Department of Biochemistry, University of Saskatchewan, 107 Wiggins Rd., Saskatoon, SK, S7N 5E5, Canada.|National Research Council of Canada, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada.
authors.forename: Michele C
authors.initials: MC
authors.lastname: Loewen
mesh_terms: D000040:Abscisic Acid / Q000737:chemistry / Q000378:metabolism; D017360:Arabidopsis / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism; D060467:Disease Resistance; D004198:Disease Susceptibility; D019143:Evolution, Molecular; D005670:Fusarium / Q000472:pathogenicity*; D020868:Gene Silencing; D008024:Ligands; D056004:Molecular Dynamics Simulation; D010802:Phylogeny; D010935:Plant Diseases / Q000382:microbiology; D010937:Plant Growth Regulators / Q000737:chemistry / Q000378:metabolism; D010940:Plant Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D014908:Triticum / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D008024:Ligands; D010937:Plant Growth Regulators; D010940:Plant Proteins; D011994:Recombinant Proteins; D000040:Abscisic Acid