Inhibitory effect of essential oil from Nepeta rtanjensis on fungal spore germination

Abstract

The ability of Nepeta rtanjensis essential oil to inhibit conidia germination of fungi was evaluated in vitro. Tested fungi included in research were Cladosporium cladosporioides, Trichoderma viride and two Alternaria species originally isolated from N. rtanjensis. The conidia of Cladosporium cladosporioides were most susceptible to the N. rtanjensis essential oil treatment, and the oil concentration of 0.1 µg ml−1 caused the maximum of conidia germination inhibition. The highest concentration used in experiment that caused the maximum of conidia germination inhibition was 0.6 µg ml−1 for Alternaria isolated from leaf surface of N. rtanjensis. The germ tube elongation of Alternaria isolates significantly decreased in response of different concentrations of oil used in experiment.

Effects of Essential Oil Citral on the Growth, Mycotoxin Biosynthesis and Transcriptomic Profile of Alternaria alternata

“…In addition, fungicidal activity was further demonstrated by the inhibition of spore germination. This result was consistent with that of Nepeta rtanjensis essential oil, which suppressed the elongation of the germ tube and spore germination, observed by light microscopy, as the concentration increased [42,43]. The sharp enhancement of fungal cell permeability was reflected by the abnormal and massive spillage of intracellular soluble proteins from macromolecular cytoplasmic components owing to cell damage by citral.…”

“…The trials of fungal spore germination were performed according to a previous method [42,53] with minor modification. The spores were collected and resuspended in sterile double distilled water, and the concentration was adjusted to 1 × 10 5 spores/mL.…”

“…After 24 h of culture, the germinating spores were terminated and dyed with lactophenol cotton blue. The spore germination was judged by the rule that the length of the germ tube must be at least half of the spore diameter, as described by Grbić et al [42]. At least 200 spores, whether germinated or not, were randomly counted and estimated.…”

Chemical composition and antifungal activity of essential oils of Algerian citrus

“…The capacity of citrus essential oils to inhibit the production and germination of spores was reported by several authors Tripathi, 2006, 2008;Chutia et al, 2009;Grbic et al, 2011). The best percentages of inhibition were presented by the oil of orange in respect to F. ox, F. sp.…”

“…; they were taken and placed on blades of glass in three specimens. The blades were incubated in an incubator at 22 ± 2°C during 48 h. For each treatment, 200 spores were examined and the germination of spores was evaluated by seeking the appearance of the tubes germinated as described by Grbic et al (2011). The spore, whose germ tube reaches 50% of its size, is considered to be germinated.…”