Submitted to: American Phytopathological Society
Publication Type: Abstract Only
Publication Acceptance Date: 4/15/2005
Publication Date: 5/20/2005
Citation: Xue, H.Q., Upchurch, R.G., Kwanyuen, P., Dewey, R. 2005. Quantification of fungal infection of soybean seed using ergosterol as an indicator of fungal biomass. American Phytopathological Society, 95:S114. Interpretive Summary:
Technical Abstract: The relationship between ergosterol content and biomass of two fungal pathogens, Diaporthe paseolorum (DPM) and Cercospora Kikuchii (CKNC) was estimated. Biomass was manipulated by varying incubation period. Ergosterol was quantified by high-pressure liquid chromatography (HPLC). Fungal dry mass was linearly correlated with ergosterol content (r2= 0.90 for DPM and r2= 0.96 for CKNC p<0.0001). Ergosterol content in free-living fungal were 3.16 ug/mg for DPM and 2.85 ug/mg for CKNC. Ergosterol content was evaluated and used to estimate the fugal biomass in inoculated and non-inoculated soybean seeds. Assay revealed that non-inoculated soybean seeds did not contain extractable ergosterol. Ergosterol content of inoculated seed was qualitatively correlated with observed seed colonization by DPM and CKNC. Soybean variety had a significant effect on fungal colonization (ergosterol content). Those results show that HPLC is a sensitive and rapid approach to determine the ergosterol content of fugally infected soybean seed and can be used as indictor of fungal biomass in soybean seed. This method can be used to detect variety difference in soybean seed susceptibility to fungal pathogens.