image: (a) Inoculation with PBS as a negative control. (b) Inoculation with a mixture of MAT-1 and MAT-2 spores. (c) Inoculation with a mixture of MAT-1 and MAT-2 supplemented with 500 μg/mL P-6 ethyl acetate extract. Scale bar is 20 μm.
Credit: Wenxia Fang, Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China
Ver-A Exhibits Broad-Spectrum Antifungal Activity
In vitro antifungal experiments demonstrate that Ver-A can inhibit the sexual mating of sugarcane smut spores at a concentration of 8 μg/mL. Additionally, it shows inhibitory activity against Aspergillus fumigatus and Candida albicans, with minimum inhibitory concentrations of 16 and 4 μg/mL, respectively. These results indicate that Ver-A possesses broad-spectrum antifungal activity.
Pot Efficacy of Ver-A Against Sugarcane Smut Disease
To evaluate the effectiveness of Ver-A against sugarcane smut disease, we conducted pot experiments. On day 20 post-inoculation, microscopic examination of sugarcane stem samples revealed mycelium in tissues inoculated with MAT-1 and MAT-2 spores. However, samples from the treatment group displayed no smut symptoms and contained only haploid spores. By day 120 post-inoculation, 80% of the plants inoculated with MAT-1 and MAT-2 spore suspension developed black spike symptoms, whereas the incidence in the P-6 ethyl acetate extract group significantly decreased to 37%, demonstrating the efficacy of fermentation extract in controlling sugarcane smut.
Mechanism of Ver-A on inhibiting sexual mating of S. scitamineum
Using real-time quantitative PCR (RT-qPCR), we quantitatively analyzed nine relevant genes associated with the pathogenicity of the sugarcane smut pathogen and the sexual mating process. The results showed that treatment with Ver-A significantly downregulated the expression levels of the mfa1 and pra1 genes, while the expression levels of bE2, bW1, bW2, mfa2, and pra2 were significantly increased. Since the mfa and pra genes are responsible for pheromone synthesis and the recognition and regulation of mating types, Ver-A disrupts the expression of these genes, thereby blocking the recognition and mating of the sugarcane smut pathogen's haploid spores, ultimately inhibiting the formation of invasive hyphae.
See the article:
Article Title
Interference with sexual mating of Sporisorium scitamineum by verrucarin A isolated from Paramyrothecium sp.
Article Publication Date
25-Nov-2024