Abstract Penicillium digitatum acidifies the extracellular environments of fruit during decay development, this pH fluctuation decreased the efficacy of biological approaches under commercial conditions. Here, we explored the interaction between P. digitatum and an antagonistic yeast Rhodosporidium paludigenum to investigate potential mechanism behind the battle. P. digitatum was found in acidified citrus fruit tissue at pH 4.25 to 3.98 as mold infection progressed. Metabonomic data showed that gluconic, glucaric, and malic acids markedly increased upon infection at pathogen-fruit interaction sites. At concentrations > 1 × 106 cells mL−1 in liquid culture containing glucose or fructose instead of lactose, R. paludigenum could effectively control green mold. High concentrations of six different acids suppressed yeast growth even in the presence of sufficient glucose. Conversely, at ≤200 mmol L−1, malic and gluconic acids promoted yeast growth in reverse. Cultivation of R. paludigenum with gluconic acid enhanced its ability to control green mold. This study provides new insights into the mechanisms by which extracellular acidification caused by acids produced by P. digitatum discriminates against competing microbes, thereby enhancing antagonistic yeast biocontrol of green mold in citrus.

中文翻译：

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用葡萄糖酸栽培紫红孢子菌增强对柑橘类青霉的杀灭效果

摘要 Penicillium digitatum 在果实腐烂发育过程中会酸化果实的细胞外环境，这种 pH 值波动会降低生物方法在商业条件下的功效。在这里，我们探索了 P. digitatum 和拮抗酵母 Rhodosporidium paludigenum 之间的相互作用，以研究战斗背后的潜在机制。随着霉菌感染的进展，在 pH 4.25 至 3.98 的酸化柑橘类水果组织中发现了 P. digitatum。代谢组学数据显示，在病原体-果实相互作用位点感染后，葡萄糖酸、葡萄糖酸和苹果酸显着增加。在含有葡萄糖或果糖而不是乳糖的液体培养物中浓度 > 1 × 106 个细胞 mL-1 时，R. paludigenum 可以有效控制绿霉菌。即使存在足够的葡萄糖，高浓度的六种不同的酸也会抑制酵母的生长。相反，在≤200 mmol L−1 时，苹果酸和葡萄糖酸会反向促进酵母生长。用葡糖酸培养 R. paludigenum 增强了其控制绿色霉菌的能力。这项研究提供了对由 P. digitatum 产生的酸引起的细胞外酸化区分竞争微生物的机制的新见解，从而增强了柑橘中绿色霉菌的拮抗酵母生物控制。