Where does the peanut smut pathogen, Thecaphora frezii, fit in the spectrum of smut diseases?

• Published in: Plant disease
• Main Authors: Arias, Silvina, Mary, Verónica Sofía, Velez, Pilar Andrea, Rodriguez, María Gisel, Otaiza González, Santiago Nicolás, Theumer, Martin Gustavo
• Format: Journal Article
• Language: English
• Published: United States 01.09.2021
• Subjects: Thecaphora frezii; effectors; peanut smut; fungal life cycle; smut diseases
• ISSN: 0191-2917
• DOI: 10.1094/PDIS-11-20-2438-FE

Smut fungi, such as Ustilago maydis, have been studied extensively as a model for plant- pathogenic basidiomycetes. However, little attention has been paid to smut diseases of agronomic importance that are caused by species of the fungus Thecaphora spp., probably due to their more localized distribution. Peanut smut by T. frezii has been reported only in South America, with Argentina being the only country where this disease has been noted in commercial species. In this work, important advances in deciphering T. frezii specific biology/pathobiology in relation to the agronomically relevant potato (T. solani), wheat (U. tritici) and barley (U. nuda) smuts are presented. The state of knowledge of fungal effectors, functionally characterized to date in U. maydis and most recently in T. thlaspeos, as well as the potential to be present in other Thecaphora species involved in dicot-host interactions like T. frezii-peanut, is summarized. We also discuss the applicability and limitations of current available methods for the identification of smut fungi in different matrices, and the management strategies to reduce their impact on the agri-food quality. To conclude, we describe some of the challenges in elucidating T. frezii strategies which allow it to successfully infect the host, and tolerate or evade plant immune defense mechanisms, as well as analysis of other aspects related to pest control and their implications for human health.