ARS | Publication request: Quantification of Fusarium virguliforme in soybean roots of partially resistant and susceptible genotypes using quantitative polymerase chain reaction

Submitted to: Phytopathology
Publication Type: Abstract
Publication Acceptance Date: April 11, 2008
Publication Date: June 1, 2008
Citation: Tang, E., Hartman, G.L. 2008. Quantification of Fusarium virguliforme in soybean roots of partially resistant and susceptible genotypes using quantitative polymerase chain reaction [abstract]. Phytopathology. 98:S154.

Technical Abstract: Soybean sudden death syndrome, caused by Fusarium virguliforme (syn. Fusarium solani f. sp. glycines), was first reported in 1971, in Arkansas. Since then, the fungus has spread to the northern United States, causing significant soybean yield losses. Soybean resistance to F. virguliforme is considered quantitative, marked by a reduction in foliar symptoms. Few studies have identified any root resistance in soybean. In this study, we developed a method to measure fungal DNA concentrations in inoculated roots and evaluated it using five soybean entries: P3981 (very susceptible), Douglas (susceptible), Forrest (intermediate), Cordell (resistant), and PI567374 (very resistant). Radicles from germinating seeds were inoculated using a mycelial plug of F. virguliforme. Four DAI, fungal DNA was extracted from the radicles and measured by quantitative PCR. The amount of F. virguliforme DNA found in Pioneer 3981 and PI 567374 was 1.46 × 10(^¿1) ng/mg and 1.96 × 10(^¿3) ng/mg of host tissue, respectively. Based on the student t-test he mean concentration of fungal DNA from Pioneer 3981 was significantly higher than that from Forrest, Cordell, and PI 567374, while PI 567374 had significantly lower fungal DNA concentrations than Pioneer 3981, Douglas, and Forrest. These results indicate that quantitative PCR has potential to quantify fungal colonization in roots and may be a useful tool for screening soybean accessions for root resistance to F. virguliforme.