First draft genome of Thecaphora frezii, causal agent of peanut smut disease

Peanut Smut in Argentina: An Analysis of the Disease, Advances, and Challenges

Peanut (Arachis hypogaea L.) is a globally high-value food crop, with Argentina ranking third in global peanut exports. However, Argentine peanut production faces a severe threat from a fungal disease, peanut smut, caused by Thecaphora frezzii. This disease is particularly prevalent in the Córdoba Province, where recent surveys have documented a gradual increase in the prevalence and incidence of peanut smut, becoming a significant challenge to peanut production. First identified in Brazil in the 1960s in wild peanut and later in Argentina in 1995 in commercial peanut fields, the disease has rapidly spread owing to its distinctive pathogen characteristics, including the lack of visible symptoms on aerial plant parts, spore spread, and survival, and with a lack of proactive efforts to develop and apply management strategies. This results in the gradual accumulation of teliospores of T. frezzii in soil, further exacerbating the problem in subsequent growing seasons by increasing the intensity of the disease and driving a reduction in crop yield and quality. This review summarizes recent research on peanut smut, focusing on disease assessment, molecular characterization, diagnosis and detection, epidemiology, host range and environmental conditions, and the latest advancements in management approaches, including fungicide spraying, breeding programs, cultural management, and biological control, aimed to enhance understanding and support effective disease management strategies in peanut production systems.

Transcriptional study of genes involved in the passage from teliospore to hyphae stage in the fungus Thecaphora frezii, the causal agent of peanut smut

Peanuts (Arachis hypogaea L.) are among the most important leguminous crops in Argentina. During the growing season, they are frequently attacked by fungal diseases, including Thecaphora frezii. The spores of T. frezii are structures that confer resistance to this phytopathogen. The transition from teliospore to hypha is a characteristic process of some fungi, which is essential for completing their life cycle. Using the transcriptomes of teliospores and hyphae of T. frezii, we aimed to identify genes that were differentially expressed during this transition, and we found 134 up-regulated and 66 down-regulated genes, which would participate in different cellular processes such as: (a) cell cycle and DNA processing; (b) cell fate; (c) rescue, defense and cellular virulence; (d) detoxification by CYP450; (e) energy; (f) nutrient interaction and nutritional adaptation; (g) metabolism; (g) proteins with binding functions or cofactor requirements; (h) stress, cell differentiation and biogenesis of cell components; and (i) transport, cell communication and transcription. The identification of genes in T. frezii and their expression levels during different stages of differentiation could contribute to our understanding of the biological mechanisms in this fungus.