Submitted to: Crop Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/15/2008
Publication Date: 7/1/2008
Citation: Hill, N., Neate, S., Cooper, B., Horsley, R., Schwarz, P., Dahleen, L.S., Smith, K., O Donnell, K., Reeves, J. 2008. Comparison of ELISA for Fusarium, Visual Screening, and Deoxynivalenol analysis of Fusarium Head Blight for Barley Field Nurseries.. Crop Science. 48:1389-1398 Interpretive Summary: Fusarium head blight (FHB) and the deoxynivalenol (DON) toxin it produces have been a continuing problem for barley since the early 1990s. Rating FHB in the field usually involves counting the number of infected kernels per spike from multiple samples per plot. Quantifying DON contamination involves grinding grain samples, extracting toxins and identifying them using GC-MS. Both these methods are labor and time intensive, and often lack repeatability across environments. An enzyme linked immunosorbant assay (ELISA) protocol was previously developed to quantify Fusarium infection in barley. The ELISA protocol was more accurate compared to field ratings and DON quantification, and gave more consistent results in detecting differences between genotypes. In vitro screens using the antigen showed that temperature and osmotic potential affected DON production in the fungus. The antigen was effective in identifying a variety of Fusarium species and is a practical alternative to FHB and DON testing in the field.
Technical Abstract: Previously we described an enzyme linked immunosorbent assay (ELISA) for quantifying Fusarium Head Blight (FHB) in barley. ELISA had lower variability than visual disease assessment or deoxynivalenol (DON) analyses. Thus we tested ELISA, DON, and visual assessment of FHB in 1) selections from a barley doubled-haploid mapping population grown in two environments and 2) the North American barley scab evaluation nursery (NABSEN) grown at four locations. All methods of evaluation had genotype x environment interactions typical of FHB experiments. Scattergrams of ELISA vs. DON and DON vs. visual estimates of FHB suggest visual symptomology is not correlated with abundance of Fusarium in grain nor the DON content after harvest. Samples that were low in ELISA were low in DON. We conducted laboratory experiments to explain how environmental parameters affect DON production by Fusarium graminearum. We also tested for abundance of the antigen specific to the antibody used in the ELISA analysis from a phylogenetically diverse set of Fusarium species and in mycelia grown under varying laboratory conditions. There was a temperature by osmotic potential effect on DON production in laboratory-grown cultures of Fusarium spp. even though growth of the fungus increased with temperature. Neither temperature, osmotic potential, nor Fusarium species had an effect on abundance of antigen in mycelia of the fungi when grown in vitro. ELISA is a more robust estimate of fungal infestation than FHB or DON individually, and is a practical alternative to dual testing for FHB and DON in plant breeding and genetic programs.