Bacha N, Echarki Z, Mathieu F, Lebrihi A
Center of Biotechnology and Microbiology, University of Peshawar, Khyber Pakhtunkhwa, Pakistan; Laboratoire de Génie Chimique, INPT-UPS, Université de Toulouse, Castanet-Tolosan Cedex, France.
J Appl Microbiol. 2015 May;118(5):1144-51. doi: 10.1111/jam.12747. Epub 2015 Feb 23.
To provide an efficient technique for monitoring the off-flavoured fungal compound geosmin.
Geosmin-associated gpe1 gene of Penicillium expansum displayed ≥99% similarity to cytochrome P450 gene of geosmin-producing P. restrictum, but ≤40% similarities to geosmin biosynthesis, non-cytochromic gene of Streptomyces avermitilis and cytochrome P450 genes of non-geosmin-producing Neotyphodium lolii, Phoma betae and P. paxilli. Serial 10-fold dilutions of P. expansum's DNA was subjected to a previously reported qPCR assay (Atoui et al. 2007), utilizing gpe1 specific primer pair 'SNgpe1F/SNgpe1R'. A linear relationship between DNA quantity and Cycle Threshold (Ct ), with strong correlative coefficient, was observed. Using the available physico-chemical method, geosmin was quantified in 188 grape samples. Penicillium spp's DNA was quantified in these samples, utilizing the developed qPCR assay. A strong positive correlation (R(2) = 0·97) between Penicillium's DNA and geosmin concentration was observed. Furthermore, <50 ng μl(-1) Penicillium's DNA corresponds to geosmin level below the permitted intensity limit i.e. 4, for 'Flavour Profile Analysis'.
Penicillium spp., genomic DNA level can provide an efficient way to quantify geosmin.
This particular qPCR technique can be utilized in numerous food industries, for the timely detection and monitoring of geosmin contamination.
提供一种监测异味真菌化合物土臭素的有效技术。
扩展青霉中与土臭素相关的gpe1基因与产土臭素的局限青霉的细胞色素P450基因相似度≥99%，但与阿维链霉菌的土臭素生物合成非细胞色素基因以及不产土臭素的黑麦草内生真菌、甜菜茎点霉和盘绒孢菌的细胞色素P450基因相似度≤40%。对扩展青霉的DNA进行10倍系列稀释，采用先前报道的qPCR检测方法（Atoui等人，2007年），使用gpe1特异性引物对“SNgpe1F/SNgpe1R”。观察到DNA量与循环阈值（Ct）之间呈线性关系，相关系数很强。采用现有的物理化学方法，对188个葡萄样品中的土臭素进行了定量。利用所开发的qPCR检测方法对这些样品中的青霉属DNA进行了定量。观察到青霉属DNA与土臭素浓度之间存在强正相关（R² = 0·97）。此外，青霉属DNA<50 ng μl⁻¹对应于土臭素水平低于“风味特征分析”的允许强度限值，即4。
青霉属的基因组DNA水平可为定量土臭素提供一种有效方法。
这种特定的qPCR技术可用于众多食品行业，及时检测和监测土臭素污染。
