Comparative pathogenicity of Fusarium graminearum isolates from China revealed by wheat coleoptile and floret inoculations

Fusarium head blight (FHB) or scab caused by Fusarium species is an economically important disease on small grain cereal crops worldwide. Accurate assessments of the pathogenicity of fungal isolates is a key obstacle toward a better understanding of the Fusarium-wheat scab system. In this study, a n...

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Bibliographic Details
Published in:Mycopathologia (1975) 2005-08, Vol.160 (1), p.75-83
Main Authors: Wu, A.B, Li, H.P, Zhao, C.S, Liao, Y.C
Format: Article
Language:English
Subjects:
bioassays
China
coleoptile inoculation
coleoptiles
Fusarium - pathogenicity
Fusarium graminearum
Gibberella zeae
infection
inflorescences
pathogenicity
Plant Diseases - microbiology
scab diseases
screening
strain differences
Triticum - microbiology
Triticum aestivum
varieties
Virulence
wheat
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Summary:Fusarium head blight (FHB) or scab caused by Fusarium species is an economically important disease on small grain cereal crops worldwide. Accurate assessments of the pathogenicity of fungal isolates is a key obstacle toward a better understanding of the Fusarium-wheat scab system. In this study, a new laboratory method for inoculation of wheat coleoptiles was developed, which consists of cutting off the coleoptile apex, covering the cut apex with a piece of filter paper soaked in conidial suspension, and measuring the lengths of brown lesions 7 days post inoculation. After coleoptile inoculation, distinct brown lesions in the diseased stems were observed, in which the presence of the fungus was verified by PCR amplification with F. graminearum Schwable-specific primers. Coleoptile inoculation of six wheat varieties indicated that a highly susceptible wheat variety was more suitable as a differentiating host for the pathogenicity assay. Analysis of the coleoptiles inoculated with a set of 58 different isolates of F. graminearum showed a significant difference in the lengths of the lesions, forming the basis by which pathogenicity of the isolates was assessed. Field inoculation of florets of three wheat varieties over 2 years revealed significant differences in pathogenicity among the 58 isolates, and that the highly resistant and highly susceptible wheat varieties were more appropriate and stable for pathogenicity assessment in field trials. Comparative analyses of eight inoculation experiments of wheat with 58 F. graminearum isolates showed significant direct linear correlations (P
ISSN:0301-486X
1573-0832
DOI:10.1007/s11046-005-1153-4