Mahmoud M A, Ali H M, El-Aziz A R M, Al-Othman M R, Al-Wadai A S
Plant Pathology Research Institute, Agricultural Research Center, Giza, Egypt.
Botany and Microbiology Department, College of Science.
Genet Mol Res. 2014 Nov 11;13(4):9352-70. doi: 10.4238/2014.November.11.2.
Twelve species from six fungal genera were found to be associated with corn (Zea mays L.) grain samples collected from three main regions of Saudi Arabia. The average frequencies of the most common genera were Aspergillus (11.4%), Fusarium (9.5%), Penicillium (5.1%), and Alternaria (5.8%). Fifteen isolates of Aspergillus flavus were screened by HPLC for their ability to produce aflatoxins (AF). The percentage of aflatoxigenic A. flavus isolates was 53%. Eight isolates produced AF, at concentrations ranging 0.7-2.9 ppb. Random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) molecular markers were used to genetically characterize isolates of A. flavus and to discriminate between the aflatoxigenic and non-aflatoxigenic isolates. RAPD and ISSR analysis revealed a high level of genetic diversity in the A. flavus population, which was useful for genetic characterization. The clustering in the RAPD and ISSR dendrograms obtained was unrelated to geographic origin. The RAPD and ISSR markers could not discriminate between aflatoxigenic and non-aflatoxigenic isolates, but the ISSR primers were somewhat better.
在从沙特阿拉伯三个主要地区采集的玉米（Zea mays L.）谷物样本中，发现六种真菌属的12个物种与之相关。最常见属的平均出现频率分别为：曲霉属（11.4%）、镰刀菌属（9.5%）、青霉属（5.1%）和链格孢属（5.8%）。通过高效液相色谱法（HPLC）对15株黄曲霉分离株产生黄曲霉毒素（AF）的能力进行了筛选。产黄曲霉毒素的黄曲霉分离株比例为53%。8株分离株产生了AF，浓度范围为0.7 - 2.9 ppb。利用随机扩增多态性DNA（RAPD）和简单序列重复区间（ISSR）分子标记对黄曲霉分离株进行遗传特征分析，并区分产黄曲霉毒素和不产黄曲霉毒素的分离株。RAPD和ISSR分析揭示了黄曲霉种群中高水平的遗传多样性，这对遗传特征分析很有用。从获得的RAPD和ISSR聚类图来看，聚类情况与地理起源无关。RAPD和ISSR标记无法区分产黄曲霉毒素和不产黄曲霉毒素的分离株，但ISSR引物在一定程度上表现更好。
