Advancements in Spongospora subterranea : current knowledge, management strategies, and research gaps

Abstract

Powdery scab was first documented on locally sampled potatoes in Braunschweig, Germany. A hundred and eighty-one years later, the disease has spread globally to most potato-producing regions and is considered one of the most destructive potato diseases. Here, we review the knowledge of powdery scab and causative agent, Spongospora subterranea f. sp. subterranea, highlighting research progress made in the last 7 years. Much work has been done to increase our understanding of how zoospores respond to their environment (e.g. root exudates, Ca2C signalling, and root metabolites) and the management of the disease by chemical and biological control agents. Recent research has utilised omics approaches — metabolomics, proteomics, and genomics — to gain a deeper understanding of the host–pathogen interaction in the powdery scab pathosystem. The management of powdery scab can be achieved using a combination of strategies that include (1) the planting of resistant potato varieties, (2) strategies that avoid disease (field selection and planting date), those that (3) reduce initial soil inoculum (crop rotation, organic soil amendments, and soil fumigation), and (4) in-crop approaches (soil chemical applications, biological control, proper field, fertility, crop, irrigation management, and crop sanitation). Lastly, we discuss research gaps for future research, including the disease’s interaction with other potato diseases that may be impacting disease expression and opportunities to enable a greater understanding of the powdery scab pathosystem.