title: Exogenous Abscisic Acid and Gibberellic Acid Elicit Opposing Effects on Fusarium graminearum Infection in Wheat.
abstract: Although the roles of salicylate (SA) and jasmonic acid (JA) have been well-characterized in Fusarium head blight (FHB)-infected cereals, the roles of other phytohormones remain more ambiguous. Here, the association between an array of phytohormones and FHB pathogenesis in wheat is investigated. Comprehensive profiling of endogenous hormones demonstrated altered cytokinin, gibberellic acid (GA), and JA metabolism in a FHB-resistant cultivar, whereas challenge by Fusarium graminearum increased abscisic acid (ABA), JA, and SA in both FHB-susceptible and -resistant cultivars. Subsequent investigation of ABA or GA coapplication with fungal challenge increased and decreased FHB spread, respectively. These phytohormones-induced effects may be attributed to alteration of the F. graminearum transcriptome because ABA promoted expression of early-infection genes, including hydrolases and cytoskeletal reorganization genes, while GA suppressed nitrogen metabolic gene expression. Neither ABA nor GA elicited significant effects on F. graminearum fungal growth or sporulation in axenic conditions, nor do these phytohormones affect trichothecene gene expression, deoxynivalenol mycotoxin accumulation, or SA/JA biosynthesis in F. graminearum-challenged wheat spikes. Finally, the combined application of GA and paclobutrazol, a Fusarium fungicide, provided additive effects on reducing FHB severity, highlighting the potential for combining fungicidal agents with select phytohormone-related treatments for management of FHB infection in wheat.
authors.affiliation: First, second, and fifth authors: National Research Council of Canada, Aquatic and Crop Resources Development, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9 Canada; third author: National Research Council of Canada, Information and Communication Technologies, 100 des Aboiteaux Street, Moncton, NB, E1A 7R1 Canada; fourth author: Agriculture and Agri-Food Canada, 5403 1st Ave S., Lethbridge, AB, T1J 4B1 Canada; and fifth author: Department of Biochemistry, University of Saskatchewan, 107 Wiggins Rd. Saskatoon, SK, S7N 5E5 Canada.
authors.forename: Leann M
authors.initials: LM
authors.lastname: Buhrow
authors.affiliation: First, second, and fifth authors: National Research Council of Canada, Aquatic and Crop Resources Development, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9 Canada; third author: National Research Council of Canada, Information and Communication Technologies, 100 des Aboiteaux Street, Moncton, NB, E1A 7R1 Canada; fourth author: Agriculture and Agri-Food Canada, 5403 1st Ave S., Lethbridge, AB, T1J 4B1 Canada; and fifth author: Department of Biochemistry, University of Saskatchewan, 107 Wiggins Rd. Saskatoon, SK, S7N 5E5 Canada.
authors.forename: Dustin
authors.initials: D
authors.lastname: Cram
authors.affiliation: First, second, and fifth authors: National Research Council of Canada, Aquatic and Crop Resources Development, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9 Canada; third author: National Research Council of Canada, Information and Communication Technologies, 100 des Aboiteaux Street, Moncton, NB, E1A 7R1 Canada; fourth author: Agriculture and Agri-Food Canada, 5403 1st Ave S., Lethbridge, AB, T1J 4B1 Canada; and fifth author: Department of Biochemistry, University of Saskatchewan, 107 Wiggins Rd. Saskatoon, SK, S7N 5E5 Canada.
authors.forename: Dan
authors.initials: D
authors.lastname: Tulpan
authors.affiliation: First, second, and fifth authors: National Research Council of Canada, Aquatic and Crop Resources Development, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9 Canada; third author: National Research Council of Canada, Information and Communication Technologies, 100 des Aboiteaux Street, Moncton, NB, E1A 7R1 Canada; fourth author: Agriculture and Agri-Food Canada, 5403 1st Ave S., Lethbridge, AB, T1J 4B1 Canada; and fifth author: Department of Biochemistry, University of Saskatchewan, 107 Wiggins Rd. Saskatoon, SK, S7N 5E5 Canada.
authors.forename: Nora A
authors.initials: NA
authors.lastname: Foroud
authors.affiliation: First, second, and fifth authors: National Research Council of Canada, Aquatic and Crop Resources Development, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9 Canada; third author: National Research Council of Canada, Information and Communication Technologies, 100 des Aboiteaux Street, Moncton, NB, E1A 7R1 Canada; fourth author: Agriculture and Agri-Food Canada, 5403 1st Ave S., Lethbridge, AB, T1J 4B1 Canada; and fifth author: Department of Biochemistry, University of Saskatchewan, 107 Wiggins Rd. Saskatoon, SK, S7N 5E5 Canada.
authors.forename: Michele C
authors.initials: MC
authors.lastname: Loewen
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology*; D003517:Cyclopentanes / Q000378:metabolism; D002523:Edible Grain / Q000187:drug effects / Q000235:genetics / Q000382:microbiology; D005670:Fusarium / Q000187:drug effects* / Q000472:pathogenicity / Q000502:physiology; D018506:Gene Expression Regulation, Plant; D005875:Gibberellins / Q000494:pharmacology*; D009183:Mycotoxins / Q000378:metabolism; D054883:Oxylipins / Q000378:metabolism; D010641:Phenotype; D010935:Plant Diseases / Q000382:microbiology / Q000517:prevention & control*; D010937:Plant Growth Regulators / Q000378:metabolism / Q000494:pharmacology*; D020156:Salicylic Acid / Q000378:metabolism; D014255:Trichothecenes / Q000378:metabolism; D014908:Triticum / Q000187:drug effects* / Q000235:genetics / Q000382:microbiology
chemical_list: D003517:Cyclopentanes; D005875:Gibberellins; D009183:Mycotoxins; D054883:Oxylipins; D010937:Plant Growth Regulators; D014255:Trichothecenes; C011006:jasmonic acid; D000040:Abscisic Acid; C007842:gibberellic acid; C007262:deoxynivalenol; D020156:Salicylic Acid
keywords: grain yield