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Oral: See the Unseen: Metatranscriptomics Unviels Plant and Vector-Pathogen Interactions


Transcriptome analysis of tanoak’s mechanisms of innate and phosphite-induced resistance to Phytophthora ramorum
K. HAYDEN (1), C. Eyre (2), P. Croucher (2), S. Schechter (2), J. Wright (3), M. Garbelotto (4) (1) Royal Botanic Garden Edinburgh, United Kingdom; (2) University of California, Berkeley, U.S.A.; (3) USDA Forest Service Pacific Southwest Research Station,

Phosphite compounds have been used in the control of sudden oak death but their precise mode of action is not fully understood. To study the action of phosphite compounds in the context of naturally occurring host resistance, we first identified open-pollinated family groups that carried resistance. Multiple inoculations were performed on previously unchallenged members of these families, half of which had been treated with phosphites. We examined gene expression during the disease response in phosphite-treated, resistant hosts (in which the treatment worked as expected); in phosphite-treated but susceptible hosts (in which phosphite was not effective nor was there innate resistance); and in untreated susceptible and resistant trees. Tanoak families differed in the presence of innate resistance and in the effectiveness of phosphite treatment. There were 9705 genes that were differentially expressed between untreated resistant trees and untreated susceptible trees. There were 7 genes differentially expressed in the same comparison between susceptible and resistant phosphite-treated trees. Our results demonstrate the differences in mode of action of phosphite compounds from innate resistance, and an intriguing lack of difference in gene expression between phosphite-treated trees, whether diseased or apparently healthy.