三株海洋木霉的应用潜力

Application potential of three marine Trichoderma spp.

摘要:

[目的] 探索3株海洋生境木霉的应用潜力。[方法] 经过筛选和诱变，获得高抑菌活性及产孢量的木霉突变株；通过优化培养基、温度、初始pH考察其产孢量及最适培养条件；综合抑菌谱、重寄生及抑菌相关基因考察其抑菌活性；采用特殊培养基法考察其产纤维素酶、植酸酶、铁载体以及降解磷钾的能力，高效液相色谱法测定其产吲哚乙酸能力。[结果] 3株木霉菌的产孢量分别为3.45×10⁸、3.10×10⁸和2.55×10⁸ CFU/cm²，与野生型相比分别提高了88.52%、63.16%和180.22%；且均可产生厚垣孢子，其中XG20-1厚垣孢子产量最高，达到3.56×10⁸ CFU/mL。3株木霉菌具有较广抑菌谱及对番茄早疫病菌的重寄生作用，同时扩增得到Tex1、Nag1、Eg1基因，生物学测试显示其均具有产纤维素酶、几丁质酶以及铁载体的能力，证明其抑菌活性是多种机制共同作用的结果；菌株可以降解磷钾，且吲哚乙酸产量分别为2.61、1.57和1.92 mg/L，具有促进植物生长的潜力。[结论] 本文中3株木霉菌在开发为生防菌与生物肥料方面展现出良好的应用潜力。

关键词:海洋生境木霉;抑菌与基因;多种酶活;降解磷钾

Abstract:

[Objective] To explore the application potential of three marine Trichoderma spp. as biocontrol agents and bio-fertilizer. [Methods] Three Trichoderma spp. with high antimicrobial activity and spore germination were selected by isolating, screening and mutagenesis. Several indicators related with application potential of these strains were tested. Sporulation capacity was measured after optimizing culture medium, temperature and initial pH. Antimicrobial activity was evaluated based on inhibition spectrum, superparasitism and related antifungal genes. Special culture method was used to determine the secretion of cellulase, phytase and siderophore, and the ability to release phosphorus and potassium. High performance liquid chromatography was used to quantify indole-3-acetic acid production. [Results] We obtained three Trichoderma spp. with the spore germinations of 3.45×10⁸, 3.10×10⁸ and 2.55×10⁸ CFU/cm², respectively. Moreover, these mutants formed chlamydospores, and strain XG20-1 had the highest chlamydospore germination of 3.56×10⁸ CFU/mL. All three strains showed a broad inhibition spectrum against 6 fungal phytopathogen and the superparasitism to Alternaria solani. Moreover, Tex1, Nag1 and Eg1 genes were found in all strains, with cellulose, phytase and siderophore detected. Indole-3-acetic acid productions in three strains were 2.61, 1.57 and 1.92 mg/L, respectively, and all three strains had the capacity of releasing phosphorus and potassium. [Conclusion] Three Trichoderma spp. had high antimicrobial activities against plant pathogenic fungi through integrated mechanism, high spore-bearing yields and growth-promoting effects on plants, which showed their potential application as biocontrol agents and bio-fertilizer.

Key words:marine Trichoderma spp.;pathogen inhibition and related gene;a variety of enzyme activity;P-releasing and K-releasing