Background

Anaerobic soil disinfestation (ASD) has been proven to be an effective and environmentally friendly method for controlling soil-borne plant diseases. Mechanisms of ASD-mediated pathogen suppression are not fully elucidated but appear to depend on the carbon (C) sources used and involve a combination of abiotic and biotic factors. This study sought to assess the impacts of ASD with different C sources on soil chemical properties, microbial activity, and antagonistic compounds, and identify the major factor(s) driving suppression of tomato bacterial wilt caused by Ralstonia solanacearum.

Methods

A pot experiment was conducted containing five treatments, i.e., untreated control (CK), anaerobic treatment without C source (ASD-CK), anaerobic treatment with rice bran (ASD-R), wheat bran (ASD-W) and peanut bran (ASD-P).

Results

All the ASD treatments significantly reduced disease incidence by 83–100% and simultaneously promoted tomato growth, while anaerobic treatments with C sources achieved a better effect than anaerobic treatment alone. This could be associated with the improved soil chemical (lowered Eh, NO₃⁻, SO₄²⁻ and elevated pH) and biological (elevated dehydrogenase and urease activities) properties and elevated production of antagonistic compounds (Fe²⁺, Mn²⁺, citric acid, succinic acid, and ammonia) by anaerobic treatments with C sources. Redundancy analysis further indicated that the elevated ammonia (11.1%, P = 0.002), Mn²⁺ (5.3%, P = 0.002), citric acid (1.8%, P = 0.046) and urease activity (1.0%, P = 0.036) were the major factors driving disease suppression, which all achieved the highest value in ASD-P.

Conclusions

In summary, the incorporation of organic materials that improve antagonistic compounds (especially ammonia) production could induce higher inhibition effect against tomato bacterial wilt during the ASD process.

中文翻译：

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厌氧土壤除虫抑制番茄青枯病并与拮抗化合物的产生有关

背景

厌氧土壤杀虫（ASD）已被证明是一种有效且环保的控制土传植物病害的方法。ASD 介导的病原体抑制机制尚未完全阐明，但似乎取决于所使用的碳 (C) 源并涉及非生物和生物因素的组合。本研究旨在评估不同碳源的 ASD 对土壤化学性质、微生物活性和拮抗化合物的影响，并确定抑制青枯病菌引起的番茄青枯病的主要因素。

方法

以未处理对照（CK）、无碳源厌氧处理（ASD-CK）、米糠厌氧处理（ASD-R）、麦麸（ASD-W）、花生糠（ASD-R）5个处理为盆栽试验。 ASD-P)。

结果

所有 ASD 处理均显着降低了 83-100% 的疾病发病率，同时促进了番茄的生长，而 C 源的厌氧处理比单独的厌氧处理取得了更好的效果。这可能与土壤化学特性（降低 Eh、NO ₃ ^-、SO ₄ ^2-和 pH 值升高）和生物特性（脱氢酶和脲酶活性升高）以及拮抗化合物（Fe ²⁺、Mn ²⁺、柠檬酸、琥珀酸和氨）通过用 C 源进行厌氧处理。冗余分析进一步表明，升高的氨（11.1%，P  = 0.002）、Mn ²⁺（5.3%，P = 0.002)、柠檬酸 (1.8%, P  = 0.046) 和脲酶活性 (1.0%, P  = 0.036) 是驱动疾病抑制的主要因素，均在 ASD-P 中达到最高值。

结论

总之，在 ASD 过程中加入可改善拮抗化合物（尤其是氨）产生的有机材料可以对番茄青枯病产生更高的抑制作用。