Isolation, Morphology, and Molecular Characteristics of Ustilago maydis from the Philippines
M. Seco and M. Balendres (24-29)
Abstract
The basidiomycete Ustilago maydis causes smut in corn (Zea mays). The pathogen was first reported in the Philippines in 1919. However, characterization data and knowledge of its current isolate for use as reference are scarce. This study provides knowledge of the morphocultural characteristics of a Laguna isolate of Ustilago maydis and, for the first time, confirms the species and identity through DNA sequencing of the partial sequence of internal transcribed spacer (ITS) in the ribosomal DNA gene region. The teliospore size (n = 30) ranged from 8.09 to 11.36 μM (averaged at 9.21 μM). Washed teliospores were successfully isolated in a potato dextrose agar (PDA) medium supplemented with CuSO4. The teliospore and the haplotype DNA (from PDA) were extracted and used in a polymerase chain reaction assay. A ~800 base pair product was amplified, and sequences of the ITS rDNA revealed teliospore and haplotype of the Philippine isolate were 100% similar to known U. maydis. Phylogenetic analysis also revealed a close resemblance of the Philippine isolate to U. maydis isolated from corn in Mexico. Description and DNA sequence information of the U. maydis Philippine isolate MBZM001 provided in this study can be used as references for future studies.