黄花倒水莲内生真菌生物活性评价及HNLF-44菌株鉴定

为充分开发黄花倒水莲(Polygala fallax)的内生真菌资源，获得具有抗植物病原真菌、抗氧化活性的内生真菌，该文以黄花倒水莲内生真菌为研究对象，使用平板对峙法检测内生真菌对6种植物病原真菌的抑菌活性，测定内生真菌发酵液的DPPH清除自由基能力和总还原能力，评价内生真菌的抗氧化活性，并对具有强抑菌活性和抗氧化活性的菌株进行形态和ITS鉴定。结果表明：(1)黄花倒水莲内生真菌中有2株内生真菌对香蕉专化尖孢镰刀菌、柑橘树脂病菌、叶点霉菌、香蕉具条叶斑病菌、茄病镰刀菌、三七根腐病菌具有明显的抑菌活性，抑菌率在50.3%～91.4%之间，其中HNLF-5对柑橘树脂病菌的抑菌率为73.2%,HNLF-44对香蕉专化尖孢镰刀菌抑菌率为91.4%。(2)内生真菌发酵液具有良好的抗氧化活性，DPPH清除率均在80%以上，总还原能力吸光值范围为0.279 2～0.748 8。(3)HNLF-44菌株为链格孢属真菌。该研究表明，药用植物黄花倒水莲内生真菌具有较好的生物活性，为后续从黄花倒水莲内生真菌中挖掘潜在新型抑菌活性和抗氧化活性物质奠定了基础。

Bioactivity evaluation of endophytic fungi of Polygala fallax and identification of HNLF-44 strain

The medicinal plant Polygala fallax has a variety of biological activities. In order to fully develop the endophytic fungi resources of the wild P. fallax and to obtain the culture-endophytic fungi strains with an anti-phytopathogenic fungi and antioxidant activities, the endophytic fungi of P. fallax were taken as the research object, the antifungal activity of the endophytic fungi against six kinds of phytopathogenic fungi was detected by the plate confrontation method; and the antioxidant activity of endophytic fungi was evaluated by measuring the DPPH free radical scavenging ability and total reducing ability of endophytic fungi fermentation broth. Finally, the endophytic fungi strains with strong antifungal and antioxidant activities were then analyzed by the morphological traits and the flanking ITS sequencing. The results were as follows:(1)In the antifungal experiment, there were two endophytic fungi of P. fallax had obvious antifungal activities on six kinds phytopathogenic fungi of Fusarium oxysporum f. sp. cubense, Phyllosticta zingiberi, Diaporthe citri, Mycosphaerella fijiensis, Fusarium solani, F. oxysporum, and the inhibition rates ranged from 50.3% to 91.4%. Among them, HNLF-5 strain had a good effect antifungal activity against Diaporthe citri, with a inhibition rate of 73.2%, and HNLF-44 strain had a good effect antifungal activity against Fusarium oxysporum f. sp. cubense, with a inhibition rate of 91.4%.(2)In the experiment of antioxidant activity, the endophytic fungal fermentation broth had good antioxidant activity, the DPPH clearance rate was above 80%, and the total reducing ability absorbance value ranged from 0.279 2 to 0.748 8.(3)It could be seen from the strain identification results that the HNLF-44 strain with antifungal activity was Alternaria sp. fungus. This study indicates that the endophytic fungi of Polygala fallax have a good ability of inhibiting plant phytopathogenic fungi and antioxidant activity, which lays the foundation for the subsequent exploration of potential new antifungal and antioxidant substances from P. fallax endophytic fungi.