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Aetiology and toxigenicity of F usarium graminearum and F . pseudograminearum causing crown rot and head blight in A ustralia under natural and artificial infection
Author(s) -
Obanor F.,
Chakraborty S.
Publication year - 2014
Publication title -
plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.928
H-Index - 85
eISSN - 1365-3059
pISSN - 0032-0862
DOI - 10.1111/ppa.12200
Subject(s) - biology , fusarium , crown (dentistry) , pathogen , inoculation , veterinary medicine , botany , horticulture , microbiology and biotechnology , medicine , dentistry
Globally fusarium head blight ( FHB ) of wheat is predominantly caused by F usarium graminearum ( FG ) and crown rot ( FCR ) by F . pseudograminearum ( FP ). While both FG and FP can cause FHB in A ustralia, the reasons why the morphologically and culturally similar FG is not a major FCR pathogen has remained elusive. Using aetiology and toxigenicity, this study clarifies the contrasting roles of FG and FP in FCR and FHB in A ustralia. Naturally infected wheat from 42 sites during 2010 FHB epidemics, and wheat inoculated with either pathogen to induce FCR or FHB at three field plantings in 2011, were used to determine pathogen prevalence and deoxynivalenol ( DON ) content of the crown, stem base, stem top, rachis and grain. As the primary aetiological agent, FP prevalence in the crown correlated with FCR severity while FG in grain and/or the rachis correlated with FHB severity. FG was an effective colonizer of the crown and stem base but colonization was symptomless. DON content was linked to FG biomass in all tissues except the crown, where FP biomass was the main contributor. Of the 30 measures derived to analyse pathogen fitness in 2011, 10 described the superior fitness of FG for FHB ; six defined FP fitness for FHB including inoculum dispersal; and eight defined FCR fitness of both FP and FG . FG had superior FHB fitness but weak saprophytic survival may have undermined its FCR fitness.