Hu Lifang, Sun Yan, Jia Ruimin, Dong Xiaomin, Shen Xihui, Wang Yang
College of Plant Protection, Northwest A&F University, Yangling, Xianyang 712100, China.
State Key Laboratory for Crop Stress Resistance and High Efficiency Production, Northwest A&F University, Yangling, Xianyang 712100, China.
Microorganisms. 2025 Aug 20;13(8):1943. doi: 10.3390/microorganisms13081943.
The biocontrol strain S10 was isolated from tomato leaf mold. The fermentation broth of strain S10 can effectively control Fusarium head blight (FHB), caused by . Enhancing antifungal activity is essential in advancing its commercialization. In this study, we aimed to improve the antifungal activity of S10 by integrating fermentation optimization and genetic engineering. Single-factor experiments revealed that seven parameters, namely corn flour, yeast extract, NaNO, CaCO, KHPO, KCl, ZnSO·7HO, and MnCl·4HO, were identified as significant components. A Plackett-Burman design (PDB) indicated that corn flour, yeast extract, and ZnSO·7HO were the most critical variables affecting its inhibitory activity and mycelial biomass. The fermentation medium was further determined based on the steepest climbing experiment and a Box-Behnken design (BBD), and the mycelial dry weight of S10 was improved from 2.13 g/L in Gauze's synthetic No. 1 medium to 8.12 g/L in the optimized medium, closely aligning with the predicted value of 7.98 g/L. Under the optimized medium, the antifungal rate of increased from 67.36 to 82.2%. The spore suspension of strain S10 cultured in the optimized medium substantially improved its biocontrol efficacy against FHB. Moreover, disruption of the key gene led to increased antifungal activity of strain S10 against . Importantly, the antifungal activity of Δ was greatly increased under the optimized fermentation medium. This study suggests that the gene negatively regulates bioactive compound biosynthesis, and the optimized medium provides favorable conditions for the growth of S10. These observations establish an extended basis for the large-scale bioactive metabolite secretion of S10, providing a strong foundation for sustainable FHB management in agriculture.
生防菌株S10是从番茄叶霉病中分离得到的。菌株S10的发酵液能有效防治由[未提及病原菌名称]引起的小麦赤霉病。提高其抗真菌活性对于推进其商业化至关重要。在本研究中，我们旨在通过整合发酵优化和基因工程来提高S10的抗真菌活性。单因素实验表明，玉米粉、酵母提取物、NaNO、CaCO、KHPO、KCl、ZnSO·7H₂O和MnCl·4H₂O这七个参数被确定为显著成分。Plackett - Burman设计（PDB）表明，玉米粉、酵母提取物和ZnSO·7H₂O是影响其抑制活性和菌丝生物量的最关键变量。基于最速上升实验和Box - Behnken设计（BBD）进一步确定了发酵培养基，S10的菌丝干重从Gauze综合一号培养基中的2.13 g/L提高到优化培养基中的8.12 g/L，与预测值7.98 g/L紧密吻合。在优化培养基下，[未提及抗真菌对象]的抗真菌率从67.36%提高到82.2%。在优化培养基中培养的菌株S10的孢子悬浮液显著提高了其对小麦赤霉病的生防效果。此外，关键基因的破坏导致菌株S10对[未提及病原菌名称]的抗真菌活性增加。重要的是，在优化发酵培养基下，Δ的抗真菌活性大大提高。本研究表明，该基因负调控生物活性化合物的生物合成，优化培养基为S10的生长提供了有利条件。这些观察结果为S10大规模分泌生物活性代谢产物奠定了基础，为农业中可持续防治小麦赤霉病提供了有力支撑。
