Antifungal effects of hydrogen peroxide and peroxidase on spore germination and mycelial growth of Pseudocercospora species

Abstract

Spore germination in Pseudocercospora abelmoschi (Ell. and Ev.) Deighton USDB 1312 and Pseudocercospora cruenta (Sacc.) Deighton USDB 1313, pathogens of Hibiscus esculentus L. and Vigna sinensis ssp. sesquipedalis (L.) van Eseltine, was significantly inhibited when incubated with different levels of hydrogen peroxide (0.03 x 10-5- 4.59 x 10-5 M H2O2) and 1-100 μg/mL peroxidase (equivalent to 1.06-106 enzyme units). Significant reduction in mycelial growth was also observed in both fungi at different levels of H2O2 (0.03 x 10-5 - 7.71 x 10-5 M) and 1-1000 μg/mL peroxidase. The spores and mycelium of P. cruenta USDB 1313 could tolerate higher levels of H2O2 (0.03 x 10-5 - 2.61 x 10-5 M) compared with that of P. abelmoschi USDB1312. The effects of peroxidase on spore germination and mycelial growth were similar in both P. abelmoschi and P. cruenta isolates. Spore germination and mycelial growth were inhibited significantly at higher levels of peroxidase. The results of this study complemented earlier field observations on the resistance or susceptibility of H. esculentus and V Sinensis ssp. sesquipedalis to both fungi.