Guest: Richard Bélanger, Université Laval, Canada
Title: Tailored deployment of soybean cultivars resistant to Phytophthora sojae through new molecular tools (BIO)
Date/Time: April 15 2025, 14:40-15:30
Location: FENS L030
Abstract:Phytophthora sojae is arguably one of the most important pathogens of soybean worldwide. A common method of control resides in the introgression of specific resistance genes (Rps) in elite material. These Rps genes have a gene-for-gene relationship with avirulence (Avr) genes of P. sojae, which triggers defense reactions. Over the years, some Rps genes have lost their efficacy as a result of adaptation by the pathogen leading to new alleles of Avr genes whose product is no longer recognized by Rps proteins. This problem is compounded by the rapid evolution of Avr genes and the fact that very few Rps genes have actually been precisely identified and cloned. Following extensive surveys of P. sojae isolates throughout soybean growing areas in Canada, we were able to define SNP haplotypes for the alleles of Avr genes associated with the most commonly deployed Rps genes, Rps1a, Rps1b, Rps1c, Rps1k, Rps3a, and Rps6. Based on this information, we have developed molecular tools that can specifically identify each haplotype of these six Avr genes found in the isolates of P. sojae recovered in soybean fields. We have further been able to identify markers that will discriminate isolates on the basis of their virulence toward the newly identified Rps11. These tools can be easily exploited by breeders to introgress a proper Rps gene and farmers to use cultivars carrying a gene known to be effective in a given region. In parallel, we have used RenSeq to precisely define Rps regions and genes, a method that has allowed a much clearer understanding of many of the reported Rps genes along with a finer resolution of their position in the soybean genome. Once optimized, this approach should facilitate introgression of Rps genes already in use and allow deployment of new sources of resistance against Phytophthora root rot.
Bio: Dr. Richard Bélanger is full professor in plant pathology, head of the Department of Plant Science and holder of a Canada Research Chair in plant protection at Laval University, Quebec. His research endeavors concentrate on the development of control methods of plant pathogens without the use of fungicides. In recent years, he and his team have worked on Phytophthora sojae and its virulence factors, the identification of resistance genes in soybean germplasm and the development of molecular tools for the proper deployment of resistant cultivars.