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Oral: Metagenomics and the Phytobiome


Soil microbiomes associated with alternative strategies to manage Verticillium dahliae
P. INDERBITZIN (1), J. Ward (2), A. Barbella (2), N. Solares (2), B. Calderon (2), D. Chellemi (2), K. Subbarao (1) (1) UC Davis, U.S.A.; (2) Driscoll’s Strawberry Associates, U.S.A.

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Verticillium dahliae is a fungal plant pathogen that causes Verticillium wilt, which results in significant losses in many crops. Control of V. dahliae is difficult as the pathogen can survive in soil without a host for over 10 years. Fumigation is an effective control, but the most viable option, methyl bromide, is no longer used and alternatives are expensive and subject to strict local regulations. Our goal is to develop environmentally-friendly and economically-viable alternatives to manage Verticillium wilt. These include organic soil amendments such as broccoli residue and a mixture of crab and feather meal, which have demonstrated disease suppressive effects in prior research, likely mediated by the soil microbiome. We performed greenhouse studies on a Verticillium sensitive host, eggplant, on which we assessed Verticillium wilt severity, and characterized soil microbial communities using 16S Illumina sequencing. The experimental setup involved a randomized complete block design with three soil amendments and 4-5 replicates for each amendment, and was performed separately for two soil types with different inoculum levels. The experiment was repeated once. We found that soil type, time of sampling, and amendment significantly impacted microbial communities; and that a sub-set of taxa was more abundant in disease suppressive treatments than in controls. Future studies will focus on the mechanistic bases of disease suppression by soilborne microbes.