Grundmann Carlismari O, Tomo Christopher, Hershelman Julia, Wolfe Benjamin E, Sanchez Laura M
bioRxiv. 2025 Sep 8:2025.09.08.674932. doi: 10.1101/2025.09.08.674932.
Microbial interactions in cheese rinds influence community structure, food safety, and product quality. But the chemical mechanisms that mediate microbial interactions in cheeses and other fermented foods are generally not known. Here, we investigate how the spoilage mold chemically inhibits beneficial cheese-rind bacteria using a combination of omics technologies. In cheese rind community and co-culture experiments, strongly inhibited most cheese rind community members. In co-culture with strongly affected bacterial gene expression, including upregulation of a putative gene cluster that is associated with resistance to antimicrobial compounds in other bacteria. Mass spectrometry imaging (MSI) revealed spatially localized production of secondary metabolites, including penicillic acid and ochratoxin B at the fungal-bacterial interface. Integration of LC-MS/MS and genome annotations confirmed the presence of additional bioactive metabolites, such as notoamides and circumdatins. Fungal metabolic responses varied by bacterial partner, suggesting species-specific chemical strategies. Notably, penicillic acid levels increased 2.5-fold during interaction with , and experiments with purified penicillic acid showed inhibition of a range of cheese rind bacteria. These findings show that deploys a context-dependent arsenal of mycotoxins and other metabolites, disrupting microbial community assembly in cheese rinds.
This study identifies the chemical mechanisms underlying the negative impacts of on cheese rind development, revealing how specialized metabolites like penicillic acid and ochratoxin B influence rind bacterial communities. By integrating biosynthetic gene cluster (BGC) analyses with mass spectrometry, we demonstrate how chemical communication shapes microbial interactions, with possible implications for food safety and cheese quality. Understanding these interactions is essential for assessing the risks of fungal driven-spoilage and mycotoxin production in cheese rind maturation. Beyond cheese, these findings contribute to broader microbiome ecology, emphasizing how secondary metabolites mediate microbial competition in natural and fermented food environments.
奶酪外皮中的微生物相互作用会影响群落结构、食品安全和产品质量。但介导奶酪及其他发酵食品中微生物相互作用的化学机制通常尚不明确。在此，我们结合多种组学技术，研究腐败霉菌如何通过化学方式抑制有益的奶酪外皮细菌。在奶酪外皮群落和共培养实验中，[具体霉菌名称]强烈抑制了大多数奶酪外皮群落成员。与[具体霉菌名称]共培养时，[具体细菌名称]的细菌基因表达受到强烈影响，包括一个假定的基因簇上调，该基因簇与其他细菌对抗菌化合物的抗性相关。质谱成像（MSI）显示在真菌 - 细菌界面有次生代谢产物的空间定位产生，包括青霉酸和赭曲霉毒素B。液相色谱 - 串联质谱（LC - MS/MS）与基因组注释相结合，证实了其他生物活性代谢产物的存在，如诺托酰胺和环带菌素。真菌的代谢反应因细菌伙伴而异，表明存在物种特异性的化学策略。值得注意的是，在与[具体细菌名称]相互作用期间，青霉酸水平增加了2.5倍，并且用纯化的青霉酸进行的实验表明其对一系列奶酪外皮细菌有抑制作用。这些发现表明，[具体霉菌名称]会部署一套依赖于环境的霉菌毒素和其他代谢产物，破坏奶酪外皮中的微生物群落组装。
本研究确定了[具体霉菌名称]对奶酪外皮发育产生负面影响的化学机制，揭示了青霉酸和赭曲霉毒素B等特殊代谢产物如何影响外皮细菌群落。通过将生物合成基因簇（BGC）分析与质谱相结合，我们展示了化学通讯如何塑造微生物相互作用，这可能对食品安全和奶酪质量产生影响。了解这些相互作用对于评估奶酪外皮成熟过程中真菌驱动的腐败和霉菌毒素产生的风险至关重要。除了奶酪之外，这些发现有助于更广泛的微生物群落生态学研究，强调次生代谢产物如何在天然和发酵食品环境中介导微生物竞争。
