Laboratory of Microbiology and Biotechnology of Foods, Department of Food Science and Human Nutrition, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece.
Laboratory of Mycology, Department of Phytopathology, Benaki Phytopathological Institute (BPI), St. Delta 8, 14561 Athens, Greece.
Toxins (Basel). 2017 Sep 22;9(10):296. doi: 10.3390/toxins9100296.
The objective of this study was to investigate the effect of environmental factors, namely temperature and water activity, on genes involved in the regulation of ochratoxin A (OTA) production over time. For this purpose, the previously characterized toxigenic Ac29 isolate from Greek vineyards and the ITEM 5010 reference strain were subjected to combined temperature and water activity (a) treatments to study OTA production and relative gene expression. The fungal isolates were grown on a synthetic grape juice liquid medium (SGM) under different temperature (20 °C, 25 °C and 30 °C) and a (0.94 and 0.98) regimes. The expression of the AcOTA, AcOTA, and OTA related genes was investigated using real time PCR. Gene expression was monitored at the same time points, along with fungal biomass and OTA accumulation at three, six and nine days of incubation. In gene expression analysis, stimulation of the biosynthetic genes was observed a few days before any toxin could be detected. This fact may underline a possible early indicator of potential toxin contamination of grapes. However, the transcript levels varied with respect to the different combinations of ecophysiological conditions and time, highlighting a complex regulation of OTA related gene expression of in the specific medium.
本研究旨在探讨环境因素（温度和水分活度）对调控赭曲霉毒素 A（OTA）产生的基因随时间变化的影响。为此，对先前从希腊葡萄园分离出的产毒 Ac29 株和 ITEM 5010 参考菌株进行了联合温度和水分活度（a）处理，以研究 OTA 产生和相对基因表达。真菌分离株在合成葡萄汁液体培养基（SGM）上于不同温度（20°C、25°C 和 30°C）和 a（0.94 和 0.98）条件下生长。采用实时 PCR 法研究 AcOTA、AcOTA 和 OTA 相关基因的表达。在三个、六个和九个培养天的时间点，监测了真菌生物量和 OTA 积累，同时监测基因表达。在基因表达分析中，在检测到任何毒素之前几天就观察到了生物合成基因的刺激。这一事实可能强调了葡萄中潜在毒素污染的可能早期指标。然而，转录水平因不同的生态生理条件和时间的组合而有所不同，突出了特定培养基中 OTA 相关基因表达的复杂调控。
