柑橘内生真菌LJZ-Y-11次生代谢产物抑菌活性研究

Antimicrobial Activity of the Secondary Metabolites from Citrus Endophytic Fungus Nemania sp.LJZ-Y-11

本文选取柑橘内生真菌Nemania sp.LJZ-Y-11进行发酵培养,提取制备其乙酸乙酯提取物并测定抑菌活性,旨在为其开发利用奠定基础。结果表明,其乙酸乙酯提取物对9种植物病原真菌和10种动物病原菌均具有显著抑制作用。处理浓度为2.5 g/L时,对9种植物病原真菌的抑制活性均超过50%,除对贡柑链格孢菌的抑制率为56.52%外,对其余8种病原菌的抑菌率均为100%,EC_(50)值在0.0048~0.1544 g/L。其中,对玉米大斑病菌、金橘砂皮病菌和烟草黑胫病菌抑菌活性最为显著,EC_(50)值分别为0.0048、0.0053和0.0067 g/L,均小于0.01 g/L;其次为辣椒炭疽病菌、茶轮斑病菌和甘蔗凤梨病菌,EC_(50)值分别为0.0227、0.0356和0.0679 g/L,均小于0.1 g/L;对甘蓝黑斑病菌和水稻胡麻叶斑病菌也有较好的抑制活性,EC_(50)值分别为0.1013和0.1544 g/L。对10种动物病原菌均具有不同程度的抑制效果,MIC值为0.0781~2.5000 g/L。其中,对枯草芽孢杆菌、大肠杆菌、金黄色葡萄球菌、蜡样芽孢杆菌、炭疽杆菌、白色念珠菌具有较强的抑菌活性,MIC值均小于0.2 g/L,其中对枯草芽孢杆菌的抑菌活性最强,MIC值为0.0781 g/L;对巨大芽孢杆菌和溶壁微球菌也有较好的抑菌活性,MIC值均为0.625 g/L;对产气肠杆菌和伤寒沙门氏菌的抑制活性相对较弱,MIC值仅为2.5 g/L。本文报道的柑橘内生真菌Nemania sp.LJZ-Y-11代谢产物具有广谱、显著抑菌活性,研究结果可为其次生代谢产物作为生物源抗菌剂开发利用提供依据。

Based on previous studies,citrus endophytic fungus Nemania sp.LJZ-Y-11 was selected for fermentation,extract preparation and evaluation of its antimicrobial activity,aiming to lay a foundation for the development and utilization of its metabolites.The antifungal and antibacterial activities of the ethyl acetate extract were determined by using a mycelium growth rate method and toxic medium coating method,respectively.The results showed that the ethyl acetate extract of LJZ-Y-11 exhibited an excellent antifungal activity against most of tested plant pathogenic fungi,and had an antibacterial activity against 10 animal pathogens to some extent.The inhibitory rate against 9 plant pathogenic fungi were all more than 50%at 2.5 g/L of the extract.Moreover,except that the inhibitory rate against Alternaria citri was 56.52%,the others were 100%.The toxicity of extract against 8 plant pathogenic fungi was determined furtherly,with EC_(50) values ranging from 0.0048 g/L to 0.1544 g/L.There was the highest inhibitory activity against Exserohilum turcicum,Diaporthe citri and Phytophthora parasitica var.nicotianae with EC_(50) values of 0.0048,0.0053 and 0.0067 g/L,respectively,less than 0.01 g/L,following by Colletotrichum capsici,Pestalotiopsis theae and Ceratocystis paradoxa with EC_(50) values of 0.0227,0.0356 and 0.0679 g/L,respectively,less than 0.1 g/L;and also had a significant inhibitory activity against Alternaria oleracea and Cochliobolus miyabeanus with EC_(50) values of 0.1013 g/L and 0.1544 g/L,respectively.In addition,the extract also showed significant antibacterial activities against 10 animal pathogens with MIC values of 0.0781-2.5 g/L.There were high inhibitory activities against Bacillus subtilis,Escherichia coli,Staphylococcus aureus,Bacillus cereus,Bacillus anthraci and Monilia albican with MIC values of less than 0.2 g/L,and had the highest inhibitory activity against Bacillus subtilis with a MIC value 0.0781 g/L.There were also strong inhibitory effects against Bacillus megaterium and Micrococcus lysodeikticus,with a MIC value of 0.625 g/L.The inhibition activity against Enterobacter aerogenes and Salmonella typhi was relatively weaker,with MIC values of 2.5 g/L.The results in this study reveal that the secondary metabolites of LJZ-Y-11 has broad-spectrum and significant antimicrobial activity against the common pathogens,providing a useful experiment basis for the development and utilization of the secondary metabolites as biological antimicrobial agents.