Exploring the Interactions Between Soil-Borne Micro-organisms

Soybean (Glycine max L.) is one of the most important crops worldwide, serving as a major source of protein and oil for both human and animal consumption. However, its productivity is constrained by soil-borne pathogens, including fungi and nematodes, which can lead to significant yield losses. Fusarium root rot (caused by F. graminearum) and soybean cyst nematode (SCN) are significant constraints on soybean production in the United States, contributing to an estimated yield loss of 88.9 million bushels in 2023. Warm and humid soil conditions favor the development of the two diseases. Therefore, we investigated the interaction between F. graminearum and SCN in a growth chamber using the susceptible cultivar ‘Williams 82.’ The experiment was designed as a completely randomized design with four treatments: F. graminearum only, SCN only, F. graminearum + SCN, and a non-inoculated control, with five replications. Each replication consisted of a "Cone-tainer" filled with river sand, with or without fungal or nematode inocula, and a 4-day pregerminated seed. At 42 days post-inoculation, there were no significant differences in plant root lengths between the F. graminearum only and F. graminearum + SCN treatments. However, plants inoculated solely with SCN had significantly shorter root lengths compared to the control. The SCN egg count was reduced in the F. graminearum + SCN treatment, suggesting that the presence of F. graminearum may influence SCN reproduction. Understanding the mechanisms behind these interactions could lead to new strategies for managing diseases involving multiple soil-borne plant pathogens.