A shift in the pathotype diversity and complexity of Phytophthora sojae, causal agent of root and stem rot of soybean, in Brazil

Abstract

Soybean root rot disease caused by the oomycete Phytophthora sojae is particularly destructive, once it is a host-specific pathogen that can infect and kill soybean plants at any stage of growth. The use of resistant cultivars is the most effective method of controlling the disease. Therefore, monitoring changes in the adaptability of P. sojae population to resistance genes (Rps) is extremely important not only from an epidemiological point of view but mainly for the management of the disease and durability of the Rps genes. We investigated the pathotypes of 40 isolates of P. sojae, sampled from the region with a higher incidence of soybean root rot in Brazil, using a set of 14 soybean differentials. The first study investigating pathotype diversity in Brazil was published in 2013. A decade later, we are reporting a major shift in pathotype diversity and complexity. This information can be useful for breeding programs aiming at developing soybean cultivars with resistance to root and stem rot and optimize the usage of genes and germplasm.