Natural Product Citronellal can Significantly Disturb Chitin Synthesis and Cell Wall Integrity in Magnaporthe oryzae

Abstract

Background: Natural products are often favored in the study of crop pests and diseases. Previous studies have shown that citronellal has a strong inhibition effect on Magnaporthe oryzae. The objective of this study was to clarify its mechanism of action against M. oryzae. Results: Firstly, the biological activity of citronellal against M. oryzae was determined by direct and indirect methods, and the results show that citronellal had a strong inhibition effect on M. oryzae with EC50 values of 134.00 mg/L and 70.48 μL/L air, respectively. Additionally, a preliminary study on its mechanism of action was studied. After citronellal treatment, electron microscopy revealed that the mycelium became thin and broken; scanning electron microscopy revealed that the mycelium was wrinkled and distorted; and transmission electron microscopy revealed that the mycelium cell wall was invaginated, the mass wall of mycelium was separated, and the organelles were blurred. The mycelium was further stained with CFW, and the nodes were blurred, while the mycelium was almost non-fluorescent after PI staining, and there was no significant difference in the relative conductivity of mycelium. In addition, chitinase was significantly enhanced, and the expression of chitin synthesis-related genes was 17.47-fold upregulated. Finally, we found that the efficacy of citronellal against the rice blast was as high as 82.14% according to indoor efficacy tests. Conclusion: These results indicate that citronellal can affect the synthesis of chitin in M. oryzae and damage its cell wall, thereby inhibiting the growth of mycelium and effectively protecting rice from rice blasts.

Antifungal Activity and Action Mechanisms of 2,4-Di-tert-butylphenol against Ustilaginoidea virens

“…virens was impacted by 2,4-DTBP. This phenomenon is consistent with the effects of dictamnine on Botryosphaeria dothidea, citronellal on Magnaporthe oryzae, and carvacrol on Alternaria alternata …”

“…However, the mycelium diaphragm in the control group appeared intact, bright, and clear, while the number and fluorescence intensity of the mycelium diaphragm gradually decreased after treatment with the increasing concentrations of 2,4-DTBP, suggesting that the cell wall integrity of U. virens was impacted by 2,4-DTBP. This phenomenon is consistent with the effects of dictamnine on Botryosphaeria dothidea, 25 citronellal on Magnaporthe oryzae, 26 and carvacrol on Alternaria alternata. 27 Effects of 2,4-DTBP on Redox Homeostasis in U. virens.…”

Storability and Linear Regression Models of Pericarp Browning and Decay in Fifty Litchi (Litchi chinensis Sonn.) Cultivars at Room Temperature Storage

“…The relative conductivity of the fruit pericarp represents the cell membrane permeability or degree of cell membrane injury, and its value increases with the degree of cell aging and damage [ 28 ]. The research results indicated that there is no difference in relative conductivity within the first 5 days of room temperature storage, a significant increase was observed starting from day 7, and the maximum value was reached at day 9, with an increase of 52.22% compared to day 0 ( Figure 4 ), indicating that the integrity of litchi fruit pericarp cell membranes can be well maintained within 5 days after harvest.…”

Anti-oomycete activities from essential oils and their major compounds on Phytophthora infestans

“…On fungi, citronellal also showed the weakest anti-fungal activity (Marei and Abdelgaleil 2018 ; Wang et al 2018 ). Citronellal showed recently to act on membrane integrity and ergosterol synthesis in the fungus Penicillium digitatum (OuYang et al 2021 ) and to disturb chitin synthesis in the fungus Magnaporthe orizae (Zhou et al 2022 ). For the oomycete Phytophthora infestans , the nature of the membrane and cell wall are different from the classical fungi with no ergosterol in the membrane and no chitin in the cell wall (Lee et al 2012 ; Wang et al 2021 ).…”