Emerging "Coffee Branch Canker" in Coffea canephora: Evidence of Fusarium decemcellulare as a potential causal agent

Coffea canephora is a crop of major socioeconomic importance in Espírito Santo State, Brazil, accounting for nearly one-third of the state’s agricultural production Field assessments have documented coffee branch canker (CBC) affecting C. canephora as an emerging disease, characterized by dieback and related symptoms. Despite the disease is now widespread in the northern region of Espírito Santo, its etiology remains unclear, as fungi from the genera Fusarium, Lasiodiplodia, and Ceratocystis have been associated with similar symptoms. In the present work, we aimed to evaluate the Fungi microbiota community of C. canephora in the field to identify the potential causal agent(s) of CBC. To achieve this, we evaluated the disease dynamics in commercial fields and conducted high-throughput sequencing of the ITS1F-ITS2 region to broadly profile fungal communities present in symptomatic and asymptomatic stem and leaf tissues. Fields surveys indicated that the coffee canker epidemic followed a logistic dynamic and did not disperse randomly but followed an aggregated spatial pattern from the initial loci of infection until near saturation of infection sites, consistent with the dynamics of a biotic disease. Fungal diversity in stem samples varied significantly between symptomatic and asymptomatic plants (P = 0.001), while the diversity in leaf samples was not significant (P = 0.097). Differential abundance analysis indicated the Fusarium decemcellulare (teleomorph: Albonectria rigidiuscula) as the only taxon with significantly higher abundance in symptomatic plants compared to asymptomatic plants (P < 0.05). Therefore, F. decemcellulare was associated to coffee branch canker affecting C. canephora as a potential etiological agent of the disease.