香茅醇和柠檬醛对茶炭疽病菌丝结构和酶活性的影响

Effects of Citronellol and Citral on Mycelial Structure and Enzyme Activity of Colletotrichum camelliae

【目的】探明香茅醇和柠檬醛对茶炭疽病(Colletotrichum camelliae)的抑菌机理,为利用植物源挥发成分防控茶炭疽病提供依据。【方法】采用二倍稀释法测定香茅醇和柠檬醛对茶炭疽病的最小抑菌浓度(MIC)和最小杀菌浓度(MBC),利用纤维素酶(CE)、丙二醛(MDA)、可溶性蛋白、超氧化物歧化酶(SOD)、过氧化物酶(POD)、琥珀酸脱氢酶(SDH)和苹果酸脱氢酶(MDH)试剂盒检测分析香茅醇和柠檬醛处理后对茶炭疽病菌丝的结构、酶活性和MDA、可溶性蛋白含量的影响。【结果】香茅醇和柠檬醛对茶炭疽病的MIC值分别为0.50 mg/mL和0.25 mg/mL,MBC值分别为1.0 mg/mL和0.5 mg/mL。香茅醇和柠檬醛最小杀菌浓度处理茶炭疽病菌丝7 d后,经扫描电子显微镜(SEM)观察到菌丝皱缩并伴有不同程度折叠、扭曲交叉和细胞表面结构严重受损;经透射电子显微镜(TEM)观察到菌体细胞膜结构完整性被破坏和内质溶解体现象。香茅醇和柠檬醛可增强CE活性而分解细胞壁上的纤维素,使细胞壁结构发生破坏;降低POD和SOD活性,降低可溶性蛋白含量,增加MDA含量,使细胞膜结构损伤;降低SDH和MDH活性而影响细胞线粒体的代谢,干扰三羧酸(TCA)循环,从而抑制菌体正常生长。【结论】香茅醇和柠檬醛能够有效抑制茶炭疽病的生长,其中,柠檬醛的抑制效果更好。

【Objective】In order to provide the basis for controlling Colletotrichum camelliae with volatile component from plant,the antibacterial mechanism of citronellol and citral against C.camelliae was explored.【Method】The minimum inhibitory concentration(MIC)and minimum bactericidal concentration(MBC)of citronellol and citral against C.camelliae were determined by double dilution method.The effects of citronellol and citral on the mycelial structure,enzyme activity,MDA and soluble protein content of C.camelliae were analyzed by kits of cellulase(CE),malondialdehyde(MDA),soluble protein,superoxide dismutase(SOD),peroxidase(POD),succinodehydrogenase(SDH)and malic dehydrogenase(MDH).【Result】The MIC values of citronellol and citral against C.camelliae were 0.50 mg/mL and 0.25 mg/mL,respectively,while the MBC values were 1.0 mg/mL and 0.5 mg/mL,respectively.After 7 days of MBC treatment of citronellol and citral,mycelium crumpled with different degrees of folding,twisting and crossing,and cell surface structure was seriously damaged under SEM observation.The damage of structural integrity and endoplasmic dissolution of cell membrane were observed under TEM.Citronellol and citral could decompose the cellulose on the cell wall by enhancing CE activity of this bacterium,thereby damaging the cell wall structure.Citronellol and citral could reduce POD and SOD activities and soluble protein content,and increase MDA content,thereby damaging cell membrane structures.Citronellol and citral could affect mitochondria metabolism by reducing SDH and MDH activities,interfere the tricarboxylic acid(TCA)cycle,thereby inhibiting the normal growth of C.camelliae.【Conclusion】Citronellol and citral can effectively inhibit the growth of C.camelliae,among which citral has the better inhibitory effect.