Field dynamics and patho-genomics of Asian soybean rust pathogen Phakopsora pachyrhizi

Soybean (Glycine max) is an important legume crop and a rich source for plant proteins and vegetable oil. A major constraint for soybean production is Asian soybean rust (ASR) which causes yield losses of up to 80%. ASR is caused by the obligate biotrophic fungus Phakopsora pachyrhizi and can only be controlled by fungicide application. Extensive efforts have been made to find genetic resistance against P. pachyrhizi however, the pathogen has rapidly overcome major resistance genes Rpp1-5. Remarkably, P. pachyrhizi infects over 153 different legume species under suitable conditions, which suggests that P. pachyrhizi maintains diverse pathogenicity factors. The degree and distribution of genetic variation in the pathogen population is key for informed deployment of novel resistance genes but is largely unknown for P. pachyrhizi. To nderstand the field variation and population structure of P. pachyrhizi, infected field samples of soybean are collected from different locations across Brazil and east Africa. We have developed a next-generation sequencing approach to explore the population structure and genetic variation of P. pachyrhizi in these very different geographic locations. Sequencing of field samples will allow us to study sequence polymorphisms in P. pachyrhizi. We will aim to obtain a detailed understanding of the effector diversity in the field population of P. pachyrhizi. We will use this information for the sustainable deployment of genes that confer resistance to Asian Soybean Rust in transgenic soybean.