目的 筛选得到能够有效防治玄参Scrophularia ningpoensis叶斑病的内生真菌，并探讨其作用机制。方法 以前期分离得到的玄参内生真菌为候选菌株，玄参叶斑病病原菌草茎点霉（Phoma herbarum，PH）为指示菌，采用平板对峙法筛选内生真菌拮抗菌株；采用活体叶片接种试验，考察内生真菌对玄参叶斑病的活体防治效果，测定玄参过氧化氢酶（catalase，CAT）防御酶、活性氧、水杨酸（salicylic acid，SA）等生理指标。采用ITS分子序列扩增对生防菌株进行菌种鉴定。结果 72株受试内生真菌中，共有28株对草茎点霉菌存在显著抑制作用，其中抑菌率最高的菌株为D90，抑菌率为（83.30±3.00）%。共有4株内生真菌对玄参活体叶斑病具有显著防治效果，分别为D1、D3、D18和D90，其病斑面积占比分别为（20.53±0.32）%、（2.07±0.05）%、（5.15±0.12）%和（1.92±0.08）%，其中D90的防治效果最好，防效为54.70%；ITS分子鉴定D90为果生刺盘孢菌Colletotrichum fructicola。接种D90后，玄参CAT酶活性得到显著提升，在接种第4、6天，PH＋D90处理组CAT酶活性显著高于叶斑病模型组，同时，D90显著提升玄参超氧阴离子自由基、木质素含量水平积累，但降低了玄参SA、NO的含量。结论 内生真菌D90能有效防治玄参叶斑病，该作用可能与诱导玄参CAT酶活性提升、活性氧的迸发及木质素含量积累有关。

Objective To screen candidate endophytic fungi for the biocontrol of Scrophularia ningpoensis leaf spot disease and reveal their mechanism. Methods Based on the endophytic fungal strains isolated from S. ningpoensis, the antagonistic strains, were screened by plate confrontation trial with Phoma herbarum (PH) while using Trichoderma harzianum (TH) as an indicator. Control effect of endophytic fungi on the leaf spot of S. ningpoensis was investigated by in vivo leaf inoculation test, and the physiological indexes including plant protective enzyme activity, reactive oxygen species (ROS) level and salicylic acid (SA) content were determined. Further, the biocontrol strains were identified by ITS molecular sequence amplification. Results Among the 72 endophytic fungi tested, a total of 28 strains had significant inhibitory effects on PH, while endophytic fungus D90 had the highest inhibitory rate 0.833% ±0.030%. The results of in vivo inoculation of leaves showed that a total of four endophytic fungi had significant control effects on the leaf spot disease of S. ningpoensis, including D1, D3, D18 and D90, with the proportion of lesion area was (20.53 ±0.32)%, (2.07 ±0.05)%, (5.15 ±0.12)% and (1.92 ±0.08)%, respectively. D90 had the best control effect, with a control effect of 54.70%. D90 was identified as Colletotrichum fructicola. CAT activity of S. ningpoensis was significantly improved after inoculation of D90; On the 4^th and 6^th day of inoculation, compared with the leaf spot model group, D90 significantly increased the superoxide anion radical and lignin content of S. ningpoensis, but decreased the content of SA and NO in S. ningpoensis. Conclusion Endophytic fungus D90 has good biocontrol potential for S. ningpoensis leaf spot disease, this may be attributed to the improvement of CAT activity, ROS burst, and lignin content accumulation.

R286.2

浙江中医药大学松阳研究院科技攻关专项（SY-Z-2024501）；浙江省重点研发计划项目（2021C04029）