ABSTRACT
Laboratory study was conducted to evaluate the effect of leaf extracts of five indigenous plant on conidia germination, growth and sporulation of Pseudoperenospora cubensis causing downy mildew disease of muskmelon. Extracts of five plant; mexican sunflower (Tithonia diversifolia), bush banana (Uvaria chamae), salt and oil tree (Cleistopholis patens), goat weed (Ageratum conyzoides) and African eggplant (Solanum macrocarpon) at Four concentrations (15, 30, 45 and 60%) were tested against the growth, conidial germination and sporulation of Pseudoperenospora cubensis in vitro. Results show that all the plant extracts significantly inhibited conidia germination and radial growth compared to the control. The extracts had no significant (p≤0.05) effect on sporulation. The rate of inhibition of growth and conidia germination was concentration dependent being highest at 60% for the extracts. The extracts of Solanum macrocarpon was the most effective followed by Ageratum conyzoides, Cleistopholis patens and Uvaria chamea whileTithonia diversifolia caused the least inhibition of growth and conidia germination. At 15, 30, 45 and 60% concentrations growth of Pseudoperenospora cubensis on PDA modified with Solanum macrocqrponwere 3.79, 3.65, 3.33 and 2.87; and 4.25, 4.12, 3.92 and 3.89 for PDA modified with Tithonia diversifolia. Similarly, conidia germination percentages recorded at same concentration of extracts S. macrocarpon were 87, 85, 70 and 62% while that of T. diversifolia were 91, 87, 84 and 72%. The study shows that the plant extracts has the potential for inhibition of the pathogen.
ABSTRACT
In the present study, we have investigated some growth conditions capable of inducing the conidial germination in Scedosporium apiospermum, S. aurantiacum, S. minutisporum and Lomentospora prolificans. Germination in Sabouraud medium (pH 7.0, 37ºC, 5% CO2) showed to be a typically time-dependent event, reaching ~75% in S. minutisporum and > 90% in S. apiospermum, S. aurantiacum and L. prolificans after 4 h. Similar germination rate was observed when conidia were incubated under different media and pHs. Contrarily, temperature and CO2 tension modulated the germination. The isotropic conidial growth (swelling) and germ tube-like projection were evidenced by microscopy and cytometry. Morphometric parameters augmented in a time-dependent fashion, evidencing changes in size and granularity of fungal cells compared with dormant 0 h conidia. In parallel, a clear increase in the mitochondrial activity was measured during the transformation of conidia-into-germinated conidia. Susceptibility profiles to itraconazole, fluconazole, voriconazole, amphotericin B and caspofungin varied regarding each morphotype and each fungal species. Overall, the minimal inhibitory concentrations for hyphae were higher than conidia and germinated conidia, except for caspofungin. Collectively, our study add new data about the conidia-into-hyphae transformation in Scedosporium and Lomentospora species, which is a relevant biological process of these molds directly connected to their antifungal resistance and pathogenicity mechanisms.
Subject(s)
Antifungal Agents/pharmacology , Scedosporium/drug effects , Spores, Fungal/drug effects , Culture Media/chemistry , Microbial Sensitivity Tests , Scedosporium/growth & development , Scedosporium/physiology , Spores, Fungal/growth & development , Spores, Fungal/physiology , Time FactorsABSTRACT
Effect of ethanolic extracts of Lawsonia inermis, Azadirachta indica, Vinca rosea, Tagetes patula, Ocimum sanctum, Colocasia antiquorum, Adhatoda vasica, Moringa oleifera, Datura metel and Curcuma longa leaf on conidial germination, mycelial growth and sporulation of Aspergillus flavus, A. niger and A. fumigatus were examined. The conidial germination of A. flavus and A. fumigatus were most inhibited by the extract of L. inermis, while that of A. niger was inhibited by A. indica. Other tested plant extracts have a good effect on conidial germination on the selected fungi. The highest mycelial growth of A. flavus (37 mm) was found in V. rosea, but in case of A. niger and A. fumigatus it (38 and 39 mm) was found in D. metel. The lowest (4, 9 and 6 mm) respectively mycelial growth of these fungi found in L. inermis. The highest sporulation (75 x 10(4)/ml) of A. flavus was counted in V. rosea, but in case of A. niger and A. fumigatus those (45 x 10(4) and 55 x 10(4)/ml) were in D. metel and the lowest (5 x 10(4), 12 x 10(4) and 9 x 10(4)/ml) respectively sporulation of these fungi counted in L. inermis plant extract medium.