Poster: Diseases of Plants: Disease Detection & Diagnosis
Interaction between a rust fungus and Colletotrichum truncatum
J. DIANESE (1), É. SOUZA (1), H. VALE (1), R. PEREIRA-CARVALHO (1) (1) DEPARTAMENTO DE FITOPATOLOGIA, UNIVERSIDADE DE BRASÍLIA, Brazil
Mixed natural infection by Uromyces and Colletotrichum species in Euphorbia hirta lead to characteristic symptoms with rust pustules surrounded by black setose acervuli, formed exclusively in the presence of the rust fungus. Besides morphologically identified with precision, U. euphorbiae, was now characterized comparing sequences of the 28S rDNA with GenBank accesses of Uromyces species. Bayesian Inference (BI) and Maximum Likelihood (ML) analyses showed that U. euphorbiae is phylogenetically close to the type species, U. appendiculatus, and well distinguished from the remaining species considered, including those pathogenic to Euphorbiaceae. The U. euphorbiae type species reported on E. hypericifolia was collected in Albany, New York, USA in 1873. As the sequences from our specimen from Brazil, far from the type location, are not suited for its epitypification, it is here designated as a reference specimen, obtained from genomic DNA extracted from teliospores, and deposited in GenBank under number: KU133293, corresponding to our herbarium voucher: UB Mycol. Col. 22311. Two Colletotrichum isolates, one endophytic from symptomless areas of the leaves, and another from an acervulus close to rust pustules were isolated. For both isolates, sequences of the ITS, GAPDH, BTUB, and HIS were obtained and subjected to BI and ML analyses. The result clearly indicated, confirming the morphological analyses, that both isolates belong to the same species, C. trucatum.