Zhou D, Wang Z, Li M, Xing M, Xian T, Tu K
Journal of Applied Microbiology
This study aimed to investigate the antifungal mechanism of carvacrol and eugenol to inhibit Rhizopus stolonifer and the control of postharvest soft rot decay in peaches.
METHODS AND RESULTS:
For antifungal mechanism, effects of carvacrol and eugenol on the mycelium growth, leakages of cytoplasmic contents, mycelium morphology, cell membrane, and membrane composition of R. stolonifer was investigated. Carvacrol and eugenol both exhibited dose-depended antifungal activity against R. stolonifer, carvacrol with the concentration of 2 μL per plant and eugenol with the concentration of 4 μL per plant inhibited fungal growth completely. The two essential oils (EOs) increased cell membrane penetrability and caused the leakage of cytoplasm, nucleic acid and protein content. The observation using scanning electron microscopy and fluorescent microscopy showed the modification of hyphal morphology and the breakage of cell plasma membrane. Decreased ergosterol contents confirmed that the two EOs could destroy the membrane of R. stolonifer. For in vivo test, the inhibition of soft rot disease and the induction of defense-related enzymes were investigated. Carvacrol and eugenol significantly reduced the incidence and severity of soft rot decay in inoculated peaches. The best treatments to control soft rot decay were obtained as 0.5 μL/L for carvacrol and 1 μL/L for eugenol. The activities of defense-related enzymes in peaches were also enhanced by the two EOs fumigation.
This study showed that carvacrol and eugenol could effectively inhibit the growth of R. stolonifer in vitro and successfully control the incidence of soft rot decay in honey peaches.
SIGNIFICANCE AND IMPACT OF STUDY:
The above findings may be the main antifungal mechanism of carvacrol and eugenol to R. stolonifer. Furthermore, carvacrol and eugenol are helpful for their commercial application on the preservation of fresh fruit.
Zhou D, Wang Z, Li M et al. Carvacrol and eugenol effectively inhibit Rhizopus stolonifer and control postharvest soft rot decay in peaches. J Appl Microbiol. 2017 Oct 17. doi: 10.1111/jam.13612.