Powdery Scab of Potato: An Evaluation of Current Molecular Resources

Spongospora subterranea f. sp. Subterranea (Sss), the causal agent of powdery scab in potatoes, is a globally important soil-borne pathogen with an obligate biotrophic lifestyle and long-lived resting spores that make it difficult to control. This paper compiles and evaluates all currently available molecular resources for Sss, including genomic, transcriptomic, proteomic, and metabolomic datasets, providing the first comprehensive overview of the pathogen's molecular research landscape. Although recent long-read assemblies have advanced the Sss genome, it has not yet reached chromosome-level resolution. A large proportion of predicted proteins remain uncharacterised, restricting the ability to identify effective targets for breeding or chemical control. Compared to other major plant pathogens, Sss remains severely under-resourced at the molecular level. This paper also summarises studies that have applied molecular tools to investigate resistance in the potato host, revealing early insights but underscoring the need for more extensive research. Overall, this short review identifies key gaps in molecular knowledge and highlights the need for a high-quality, chromosome-level reference genome and improved annotation through post-genomic analyses to support more effective and targeted management strategies for powdery scab disease of potato.