Effectoromics as a tool for better management of soybean root/stem rot   
J. MCDOWELL (1), K. Fedkenheuer (1), M. Fedkenheuer (1), C. Davis (1), S. Maroof (1), B. Tyler (2), A. Robertson (3) (1) Virginia Tech, U.S.A.; (2) Oregon State University, U.S.A.; (3) Iowa State University, U.S.A.

The oomycete Phytophthora sojae causes a root and stem rot disease of cultivated soybean (Glycine max), with estimated annual costs of $1-3 billion worldwide. To identify new R genes against P. sojae, we developed a strategy that combines traditional, pathogen-based screens with effectoromics, in which we deliver P. sojae RXLR effector proteins one at a time and screen for a resistance response, indicative of an Rps gene that recognizes that effector. An important component of this strategy is to identify Rps genes that recognize RxLR effectors that are important for virulence (i.e., non-redundant) and are conserved in P. sojae. Such Rps genes are expected to provide durable resistance against a broad spectrum of P. sojae field isolates. We identified core RxLR effectors that are strongly induced during early infection, conserved amongst P. sojae isolates, and make major contributions to virulence.  We also conducted pathogen-based screens of ~1100 accessions of Glycine max and its wild relative, G. soja, to identify accessions with putative novel Rps genes. We probed these P. sojae-resistant accessions for recognition of important RxLR effectors, using a Pseudomonas-based screening system. We have identified accessions of G. max and G. soja that recognize important RxLR effectors, and we are now using recombinant inbred populations to map the R genes and validate their utility under field conditions. 

Abstract Number: P19-705, C3-2
Session Type: Poster