Antifungal Activity and Action Mechanism of Ginger Oleoresin Against Pestalotiopsis microspora Isolated From Chinese Olive Fruits

Abstract

Pestalotiopsis microspora (P. microspora) is one of dominant pathogenic fungi causing rotten disease in harvested Chinese olive (Canarium album Lour.) fruits. The purposes of this study were to evaluate the antifungal activities of ginger oleoresin (GO) against P. microspora and to illuminate the underlying action mechanisms. The in vitro assays indicate that GO exhibited strong antifungal activity against mycelial growth of P. microspore, and with 50%-inhibition concentration (EC50) and 90%-inhibition concentration (EC90) at 2.04 μL GO and 8.87 μL GO per mL propylene glycol, respectively, while the minimal inhibitory concentration (MIC) and minimal fungicidal concentration were at 10 μL GO and 30 μL GO per mL propylene glycol, respectively. Spore germination of P. microspora was inhibited by GO in a dose-dependent manner, and with 100% inhibition rate at the concentration of 8 μL GO per mL propylene glycol. Compared to the control, the cellular membrane permeability of P. microspora increased due to severe leakage of intercellular electrolytes, soluble proteins, and total sugars with the treatments (EC50, EC90) by GO during incubation. In addition, analysis of fatty acid contents and compositions in cellular membrane by GC-MS indicated that GO could significantly promote the degradation or peroxidation of unsaturated fatty acids in P. microspore, resulting in the enhancement of membrane fluidity. Moreover, observations of microstructure further showed the damage to plasma membrane and morphology of P. microspora caused by GO, which resulted in distortion, sunken and shriveled spores and mycelia of the pathogen. Furthermore, in vivo assay confirmed that over 3 MIC GO treatments remarkably suppressed disease development in P. microspore inoculated-Chinese olive fruit. These results demonstrate that owing to its strong antifungal activity, GO can be used as a promising antifungal agent to inhibit the growth of pathogenic fungi in Chinese olives.

Recovery of Polyphenolic Fraction from Arabica Coffee Pulp and Its Antifungal Applications

“…We believe that as an endophyte pathogen, it is able to repel natural products synthesised within the plants per se, thereby requiring a higher concentration for fungal inhibition. Such a mechanism has been described previously [ 52 ]. Finally, the report on antifungal effects of P. breviseta has not been documented anywhere.…”

“…and P. breviseta was 0.09, 0.31 and 0.14 g/mL, respectively ( Table 4 ). Chen et al [ 52 ] reported a minimum concentration of crude extract that was able to inhibit conidial germination of A. solani at the lowest (0.19 mg) concentration after a 72 h incubation period. However, the chemical profile of the extract was not reported.…”

Ecological Implications of Plant Secondary Metabolites - Phytochemical Diversity Can Enhance Agricultural Sustainability

“…Oleoresin, which has antifungal properties against Pestalotiopsis microspora (Chen et al, 2018), is made up of triterpenes, some of which are oleanane saponins (Liang et al, 1988). The release of flavonoids from alfalfa seeds and roots slows growth of parasitic species of Pythium spp.…”

ANTIFUNGAL ACTIVITY OF EXTRACTS AGAINST Colletotrichum SPECIES IN HARVESTED CHILI

“…Ginger has several volatile compounds such as á-pinene, borneol, camphene, and linalool which responsible for antimicrobial activities (Liu et al, 2017). According to Chen et al (2018), ginger oleoresin effectively inhibited mycelial growth and spore germination of P. microspore through in vitro study. Liu et al (2017) reported that antifungal activities of crude extracts including ginger made by hot water extract effectively inhibited Phoma exigua, Fusarium nygamai, and R. solani through in vitro technique.…”