桧木醇对西瓜枯萎病菌的抑制作用

Antifungal effect of hinokitiol against Fusarium oxysporum f.sp.niveum

由尖孢镰刀菌西瓜专化型(Fusarium oxysporum f. sp. niveum,FON)引起的西瓜枯萎病是一种毁灭性的土传病害。本研究通过离体及活体试验,测定了植物源天然抑菌活性物质桧木醇对西瓜枯萎病菌的抑制活性、对西瓜枯萎病的盆栽防效以及对病原菌生理生化指标的影响。结果表明:桧木醇对西瓜枯萎病菌具有明显的抑制效果,其对病原菌菌丝生长和孢子萌发的抑制作用EC_(50)值分别为31.1和45.2μg/mL;在250、500和1000μg/mL 3个质量浓度下,桧木醇对西瓜枯萎病均有显著的防治效果,其中1000μg/mL时防效可达75.2%,与对照药剂多菌灵500μg/mL的效果相当。生理生化指标测定及外观形态观察发现,经桧木醇处理后,西瓜枯萎病菌菌丝相对电导率上升,菌丝体内镰刀菌酸含量显著降低,菌丝呈现扭曲、畸形、缠绕等不规则外观形态。研究表明,桧木醇不仅能显著抑制西瓜枯萎病菌的生长,同时能抑制其相关毒素的生物合成或促进其代谢,从而降低病原菌的致病力,具有开发为西瓜枯萎病防治替代药剂的潜力。桧木醇处理能破坏病原菌细胞膜的完整性、干扰病原菌次生代谢物的合成或代谢过程,但其具体的抑菌分子靶标仍需进一步研究。

Watermelon fusarium wilt caused by Fusarium oxysporum f.sp.niveum(FON),is a devastating soil-borne disease that seriously damages watermelon production worldwide.Through in vitro and in vivo assays,the inhibition activity of hinokitiol on FON,control efficacy to fusarium wilt of watermelon,and its effect on the physiological and biochemical indexes of FON were determined.The results showed that hinokitiol had an obvious effect against FON,and its EC50 values for inhibition of mycelial growth and spore germination were 31.1 and 45.2μg/mL,respectively.The pot tests showed that all the three different concentrations(250,500 and 1000μg/mL)of hinokitiol had significant inhibitory effects on the fusarium wilt of watermelon.The control efficacy was 75.2%when the concentration of hinokitiol was 1000μg/mL,which was comparable to that of the control agent carbendazim at a concentration of 500μg/mL.The tests of physiological and biochemical indicators showed that the relative electrical conductivity of FON increased and the content of fusaric acid significantly declined.The mycelium showed irregular shapes such as distortion,deformity,and entanglement after treatment with hinokitiol.These results suggested that hinokitiol could not only significantly inhibit the growth of FON,but also inhibit the synthesis of toxins and reduce the pathogenicity.Hinokitiol has the potential to be developed as an alternative fungicide for the control of watermelon fusarium wilt.Hinokitiol destroys the cell membrane integrity of the pathogen,but its specific antifungal mechanism still needs further study.