芳樟醇对生姜枯萎病菌的抑制作用

Inhibitory Effect of Linalool against the Ginger Fusarium Wilt Pathogen

为明确芳樟醇对生姜枯萎病菌尖孢镰刀菌(Fusarium oxysporum)的抑菌效果与作用机制,以不同质量浓度的芳樟醇处理尖孢镰刀菌,对尖孢镰刀菌菌丝体生长、孢子萌发和细胞膜的损伤以及防治效果进行系统研究。结果表明:芳樟醇可显著抑制尖孢镰刀菌的菌丝生长,其半数有效浓度为1.183 g/L,最小抑菌浓度(minimal inhibitory concentration,MIC)为2.0 g/L,抑制效果与芳樟醇质量浓度呈剂量效应关系;以芳樟醇MIC处理尖孢镰刀菌6 h,其孢子浓度为(1.43±0.12)×10^(4)spores/mL,显著低于对照组((5.79±0.19)×10^(4)spores/mL)(P<0.05);MIC芳樟醇处理枯萎病菌尖孢镰刀菌12 h,其孢子萌发率仅为(5.83±2.16)%,显著低于对照组((95.12±3.78)%)(P<0.05)。1/2 MIC与MIC芳樟醇处理破坏了细胞膜的完整性,导致菌丝悬液中相对电导率、核酸渗漏量显著增加,菌丝中丙二醛浓度也显著增加,麦角固醇含量显著降低,减弱了尖孢镰刀菌的致病力;MIC芳樟醇处理3 d后姜块上没有病斑产生,有良好的防治效果。综上所述,芳樟醇通过抑制生姜枯萎病菌尖孢镰刀菌菌丝生长与孢子萌发、破坏细胞结构从而影响其正常的生理功能,本研究可为防治生姜枯萎病提供新思路。

To study the antifungal effect and mechanism of linalool against Fusarium oxysporum FOX-1,the causative agent of ginger Fusarium wilt,the damaging effects of different concentrations of linalool on the mycelial growth,spore germination and cell membrane of F.oxysporum FOX-1,and its control effect on ginger Fusarium wilt were systemically investigated.The results showed that linalool could significantly inhibit the mycelial growth of F.oxysporum FOX-1 in a concentration-dependent manner,and the half maximal effective concentration(EC50)and the minimum inhibitory concentration(MICs)were 1.183 and 2 g/L,respectively.The spore concentration of F.oxysporum FOX-1 treated with linalool at MIC for 6 h was(1.43±0.12)×10^(4)spores/mL,which was significantly lower than that of the control group((5.79±0.19)×10^(4)spores/mL)(P<0.05),and the spore germination rate of F.oxysporum FOX-1 treated with linalool at MIC for 12 h was(5.83±2.16)%,which was significantly lower than that of the control group((95.12±3.78)%)(P<0.05).Treatment with linalool at 1/2 MIC and MIC damaged the integrity of the cell membrane,resulting in a significant increase in relative electrical conductivity and nucleic acid leakage in the mycelial suspension and malondialdehyde(MDA)content in the mycelium,and a significant decrease in ergosterol content,finally weakening the pathogenicity of the fungus.No lesions appeared on ginger pieces after treatment with linalool at MIC for 3 days.In conclusion,linalool affects the normal physiological function of F.oxysporum FOX-1 by inhibiting its spore germination and mycelial growth and destroying its cellular structure.This study provides a new direction for the effective control of Fusarium wilt.