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Poster: Biology & Disease Mgmt: Oomycetes


Temporal analysis of oomycete communities associated with soybean and corn
M. CHILVERS (1), J. Rojas (1) (1) Michigan State University, U.S.A.

Corn and soybean rotation is typically practiced in field crop production, with the purported benefit of reducing pathogen inoculum density. This management practice has been studied before with concentration on a single pathogen species. There is limited information on how the associated oomycete community is modulated by using different crops in the rotation. We hypothesized that the genetic background of the hosts and their different growth stages could have an effect on the associated oomycete community. In 2013-14, field trials including two soybean cultivars (cv. Sloan and Archer) and two corn cultivars (cv. DK5261 and P0255AMXT) were planted in in a randomized block design with non- and inoculated treatments. The inoculated treatment consisted of a mixed inoculum of equal parts of Pythium irregulare, Py. sylvaticum, Py. ultimum, Py. heterothallicum, Py. oopapillum and Phytophthora sojae colonized rice. Soil and root samples were collected at different growth stages and subjected to DNA extraction. Samples were sequenced for ITS 1 amplicons. The results showed a variability in community composition between the two crops, however cultivars did not significantly vary in community composition despite different genetic backgrounds. Host could play an important role in filtering the associated oomycete community, however it did not effectively change the composition, suggesting this specific rotation system might not be conducive to pathogen inoculum reduction.