醉马草-内生真菌共生体中生物碱的抑菌活性

Antifungal activity of the crude extraction of endophyte-infected and endophyte-free drunken horse grass

本研究以Epichloё属内生真菌侵染(E+)和未被侵染(E-)的醉马草(Achnatherum inebrians)生物碱提取液为材料,测定其对麦角菌(Clavieps purpurea)、德氏霉(Drechslera erythrospila)、燕麦镰孢(Fusarium avenaceum)、根腐离蠕孢(Bipolaris sorokiniana)、新月弯孢(Curvularia lunata)、半裸镰孢(Fusarium semitectum)、腐皮镰孢(Fusarium solani)和细交链孢(Alternaria alternata)8种植物病原真菌菌落生长和孢子萌发的抑制率,明确醉马草生物碱提取液的抑菌活性。高效液相色谱(HPLC)检测结果发现,E+醉马草提取液中含有麦角新碱和麦角酰胺两种生物碱,其浓度分别为26.178和369.074 mg·kg-1,而E-醉马草提取液中不含这两种生物碱。不同浓度的E+和E-醉马草提取液对供试植物病原真菌的菌落繁殖和孢子萌发均具有不同程度的抑制作用,E+对真菌菌落生长的抑制率要大于E-,其中对腐皮镰孢菌落生长和孢子萌发的抑制率最大,分别达到63%和57%。生物碱提取液浓度与供试真菌孢子萌发抑制率呈显著正相关(P<0.05)。内生真菌的侵染提高了醉马草提取液的抑菌活性,共生体中含有生物碱成分,具体的抑菌机制和机理有待后续研究。

Antifungal activities of the alkaloid extraction from endophyte-infected(E +) and endophyte-free(E-) Achnatherum inebrians were tested against Claviceps purpurea,Drechslera erythrospila,Fusarium avenaceum,Bipolaris sorokiniana,Curvularia lunata,F.semitectum,F.solani and Alternaria alternata to definite the bacteriostatic activity of drunken horse grass(Achnatherum inebrians) alkaloid extract.The results of HPLC analysis found that ergot alkaloids,ergonovine and ergine were existed in the E + drunken horse grass.The concentrations were 26.178 and 369.074 mg·kg-1,but these two alkaloids were not detected in the E-extraction.The alkaloid extraction from E + and E-drunken horse grass inhibited the colony growth and spore germination of the 8 fungi differently,extraction from E + had stronger inhibition to tested fungi than E-.The inhibition rate of E + alkaloid extraction to the colony growth and spore germination of F.avenaceum was the highest with 63% and 57%,respectively.The concentration of alkaloid extraction and the spore germination inhibition rate of tested fungi was significantly positive correlation(P<0.05).Fungi of grass endophyte infection increased the antifungal activity of drunken horse grass extraction.The symbionts contained alkaloids ingredients,however.the specific chemical substances of the extractions and the mechanism of antifungal activity need further research.