TiFN, P.O. Box 557, 6700 AN Wageningen, the Netherlands; Microbiology, Utrecht University, Padualaan 8, 3584 CH Utrecht, the Netherlands.
TiFN, P.O. Box 557, 6700 AN Wageningen, the Netherlands; Westerdijk Fungal Biodiversity Institute, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands.
Food Res Int. 2020 Oct;136:109287. doi: 10.1016/j.foodres.2020.109287. Epub 2020 May 19.
Penicillium roqueforti is a major cause of fungal food spoilage. Its conidia are the main dispersal structures of this fungus and therefore the main cause of food contamination. These stress resistant asexual spores can be killed by preservation methods such as heat treatment. Here, the effects of cultivation time and temperature on thermal resistance of P. roqueforti conidia were studied. To this end, cultures were grown for 3, 5, 7 and 10 days at 25 °C or for 7 days at 15, 25 and 30 °C. Conidia of 3- and 10-day-old cultures that had been grown at 25 °C had D-values of 1.99 ± 0.15 min and 5.31 ± 1.04 min, respectively. The effect of cultivation temperature was most pronounced between P. roqueforti conidia cultured for 7 days at 15 °C and 30 °C, where D-values of 1.12 ± 0.05 min and 4.19 ± 0.11 min were found, respectively. Notably, D-values were not higher when increasing both cultivation time and temperature by growing for 10 days at 30 °C. A correlation was found between heat resistance of conidia and levels of trehalose and arabitol, while this was not found for glycerol, mannitol and erythritol. RNA-sequencing showed that the expression profiles of conidia of 3- to 10-day-old cultures that had been grown at 25 °C were distinct from conidia that had been formed at 15 °C and 30 °C for 7 days. Only 33 genes were upregulated at both prolonged incubation time and increased growth temperature. Their encoded proteins as well as trehalose and arabitol may form the core of heat resistance of P. roqueforti conidia.
青霉（Penicillium roqueforti）是导致真菌性食物腐败的主要原因。其分生孢子是这种真菌的主要扩散结构，也是食物污染的主要原因。这些具有抗应激能力的无性孢子可以通过热处理等保存方法杀死。在这里，研究了培养时间和温度对青霉（Penicillium roqueforti）分生孢子耐热性的影响。为此，将培养物在 25°C 下培养 3、5、7 和 10 天，或在 15、25 和 30°C 下培养 7 天。在 25°C 下培养 3 天和 10 天的培养物的分生孢子的 D 值分别为 1.99±0.15 分钟和 5.31±1.04 分钟。培养温度的影响在 15°C 和 30°C 下培养 7 天的青霉（Penicillium roqueforti）分生孢子之间最为明显，D 值分别为 1.12±0.05 分钟和 4.19±0.11 分钟。值得注意的是，在 30°C 下培养 10 天时，既增加培养时间又增加温度并不会使 D 值升高。发现分生孢子的耐热性与海藻糖和阿拉伯糖醇的水平相关，但与甘油、甘露醇和赤藓糖醇无关。RNA 测序表明，在 25°C 下培养 3 天至 10 天的分生孢子的表达谱与在 15°C 和 30°C 下培养 7 天形成的分生孢子不同。只有 33 个基因在延长孵育时间和提高生长温度时都被上调。它们编码的蛋白质以及海藻糖和阿拉伯糖醇可能构成了青霉（Penicillium roqueforti）分生孢子耐热性的核心。
