Fungal Community Analysis of Heterodera schachtii Females Derived from Imperial Valley (CA) Soils Cropped to Sugar Beets

The goal of this study was to obtain evidence supporting the feasibility of a new cropping decision model for sugar beet production in the Imperial Valley of California. We hypothesize that growers can use this model to create and maintain soils that suppress the sugarbeet cyst nematode (Heterodera schachtii) by manipulating the population densities of indigenous soil microbes belonging to a group of nematophagous fungi comprised of Hyalorbilia oviparasitica and relatives - the H. oviparasitica Clade. In this study, 21 of 25 Imperial Valley soils, which were recently cropped to sugar beets, harbored members of the H. oviparasitica Clade. The population densities of these fungi also increased approximately 10,000-fold in the presence of H. schachtii and a H. schachtii host crop over one nematode generation. These results support the feasibility of our new cropping decision model because not only will the presence of indigenous members of the H. oviparasitica Clade be essential, but we also posit that their population densities will need to rapidly expand to create the H. schachtii suppressive soils. Finally, an Illumina-based, fungal rRNA ITS assay was used to characterize the fungi associated with H. schachtii females derived from these soils.