三个木霉菌株防病促生效应

Diseases control and plant growth promotion effect of three Trichoderma strains

摘要:

【背景】木霉(Trichoderma sp.)是重要的生防微生物资源，对不同的木霉菌株进行生物学特性比较，可为获得功能较广的复配型生防菌剂提供参考信息。【目的】通过对绿木霉(Trichoderma virens) T23、哈茨木霉(Trichoderma harzianum) T22、G30的防病效果及对作物的促生潜力等生物学特性进行比较分析，明确不同菌株的生物功能差异。【方法】用平板拮抗法比较分析菌株T23、T22、G30对植物病原真菌的拮抗效果；用乙酸乙酯萃取法对菌株T23、T22、G30培养液中的胶毒素进行提取并通过高效液相色谱法(high-performance liquid chromatography, HPLC)检测胶毒素；用打孔法比较分析培养液萃取物对植物病原真菌的拮抗效果；通过温室接种验证菌株T23、T22、G30的防病效果；分别以磷酸钙、卵磷脂为唯一磷源检测菌株T23、T22、G30对难溶性磷的转化利用潜力，用电感耦合等离子发射光谱法(inductively coupled plasma-atomic emission spectrometry, ICP-AES)检测有效磷含量；用透明圈法或显色法分析菌株T23、T22、G30主要生理生化特性。【结果】菌株T23、T22、G30对茄镰孢(Fusarium solani)的平板拮抗率分别为77%、74%、48%；对齐整小核菌(Sclerotium rolfsii)的拮抗率分别为80%、67%、24%；对灰葡萄孢(Botrytis cinerea)的拮抗率分别为93%、62%、64%；菌株T22、G30基因组中均不携带胶毒素合成基因簇，培养液中均未检测到胶毒素；菌株T23培养液提取物对齐整小核菌、灰葡萄孢的抑菌率分别为40%、65%；温室接种结果表明，在齐整小核菌胁迫下，T23可显著提高花生成苗率，达68%；在灰葡萄孢胁迫下，菌株T23可使月季延迟16 d发病；菌株T23、T22可以产生β-1,3-葡聚糖酶；菌株T23、T22、G30可对磷酸钙进行转化利用。【结论】通过比较分析，我们对菌株T23的防病促生效果及生理生化特性有了进一步了解。菌株T23、T22、G30在植物病原真菌拮抗、解磷效果方面各具特点及优势，菌株T23通过产生抑菌性天然产物来拮抗病原真菌，这为真菌源生物农药的开发提供了重要的来源。在促生方面，菌株T23的无机磷转化机制有待进一步研究。

关键词:木霉;胶毒素;植物病原真菌;生物学特性;解磷微生物

Abstract:

[Background] Trichoderma sp. is an important biocontrol microorganism. Comparing the biological characteristics of different strains can provide information for multi-function biocontrol agent development. [Objective] To figure out the biological function differences among different strains by comparing and analyzing the preventive effects of Trichoderma virens T23 and the other two Trichoderma harzianum strains T22 and G30 and their biological characteristics. [Methods] Plate antagonism test was employed to compare the antagonistic effects of strains T23, T22, and G30 on plant pathogenic fungi. Gliotoxin was extracted from culture solution of strains T23, T22, and G30 by ethyl acetate extraction method and tested by high-performance liquid chromatography (HPLC). The antagonistic effects of the extracts on plant pathogenic fungi were compared by the hole drilling method, and the effects of strains T23, T22, and G30 on disease prevention were verified by plant inoculation in the greenhouse experiments. The conversion and utilization potential of strains T23, T22, and G30 to insoluble phosphorus was determined by using calcium phosphate and lecithin as the only phosphorus sources, respectively, and inductively coupled plasma-atomic emission spectrometry (ICP-AES) was used for soluble phosphate detection. The main physiological and biochemical characteristics of strains T23, T22, and G30 were analyzed by the transparent ring method or chromogenic method. [Results] The plate antagonism rate of strains T23, T22, and G30 against Fusarium solani was 77%, 74%, and 48%, respectively, against Sclerotium rolfsii was 80%, 67%, and 24%, respectively, and against Botrytis cinerea was 93%, 62%, and 64% respectively. Neither strain T22 nor strain G30 carried gene clusters participating in gliotoxin biosynthesis, and no gliotoxin was detected in the culture solution of strains T22 and G30. The antibacterial rate of strain T23 extracts against S. rolfsii and B. cinerea was 40% and 65%, respectively. In the greenhouse experiment, strain T23 improved the emergence percentage (68%) of peanut seedlings under S. rolfsii stress and delayed the onset of disease in Rosa chinensis Jacq. for 16 days under B. cinerea stress. Strains T23 and T22 produced β-1,3-glucanase. Strains T23, T22, and G30 all possessed the ability to transform and utilize calcium phosphate. [Conclusion] Through comparative analysis, we have a further understanding of the disease prevention and growth-promoting effect of strain T23 and its physiological and biochemical characteristics. Strains T23, T22, and G30 have their characteristics and advantages in fungi antagonism and phosphorus solubilization. Strain T23 antagonizes pathogenic fungi by producing bacteriostatic natural products, which provides an important source for the development of fungus-derived biopesticides. In terms of growth promotion, the inorganic phosphorus solution mechanism of strain T23 needs to be further studied.

Key words:Trichoderma sp.;gliotoxin;plant pathogenic fungi;biological characteristics;P-solubilizing microbes