FIRST REPORT IN MEXICO OF PENICILLIUM BREVICOMPACTUM CAUSING CORM ROT OF GLADIOLUS GRANDIFLORUS IN STORAGE
E. González-Pérez, M.J. Yáñez-Morales
A disease causing corm rot of gladiolus in storage was studied in San Martin Texmelucan, Puebla (Mexico) in 2011. Stored corms with rot symptoms were collected and disinfected superficially with 1.5% sodium hypochlorite for 3 min, rinsed three times in sterile water and placed in potato carrot agar plates at 21°C for eight days under continuous black light (40W). The fungus commonly isolated from diseased gladiolus corms differed from those currently known to occur in this crop in Mexico (González-Pérez et al., 2009) and was identified as Penicillium brevicompactum Dierckx according to Frisvad and Samson (2004). Successful isolation was obtained from 25% of 640 analyzed corms. Experiments for fulfilling Koch’s postulates were carried out under aseptic conditions using disinfested healthy corms. The corms (wounded or not) were inoculated with a conidial suspension of 11.6x108 conidia ml-1. Controls were inoculated with only distilled sterile water. Corm rot symptoms were evaluated 30 days post inoculation. P. brevicompactum caused moderate rot in inoculated corms, whereas the controls remained healthy. P. brevicompactum was re-isolated from the margins of lesions developed on inoculated corms. The morphological identification was confirmed by DNA sequence data of the ß-tubulin gene (GenBank accession No. FJ012879). This finding represents the first record of this pathogenic species associated with corm rot of gladiolus in Mexico.