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成都市售辣椒中产黄曲霉毒素菌株的分离及其基因分析

Isolation and Study on the Aflatoxin Genes of Aflatoxin-producing Fungi in Paprika Samples in Chengdu

  • 摘要: 目的 从成都市售辣椒粉中,分离产黄曲霉毒素的菌株,探究产毒基因AflR、Omt-1和Ver-1与产黄曲霉毒素B1(AFB1)能力的关系。方法 采用传统培养法分离菌株,多重PCR方法筛查潜在产黄曲霉毒素菌株,对潜在产黄曲霉毒素菌株进行产毒培养,以ELISA方法检测潜在产毒株7 d产毒培养液中AFB1含量;同时基于潜在产毒株的产毒关键基因AflR、Omt-1和Ver-1构建系统进化树,分析其同源性。结果 64份辣椒样品中,分离到17株潜在产AFB1的黄曲霉菌株,有11株分离株产毒,产毒黄曲霉分离率为64.71%;且基于AflR、Omt-1和Ver-1基因与产毒标准菌株有较高同源性;有6株分离株不产毒,与米曲霉序列有较高同源性。结论 控制黄曲霉污染是黄曲霉控制中重要的环节之一。并非含有产毒基因的黄曲霉都会产AFB1毒素,产AFB1能力与产毒基因AflR的序列有着直接联系,而AFB1合成量的高低与Omt-1和Ver-1基因有关。

     

    Abstract: Objective To isolate aflatoxin-producing strains from paprika samples and to do a preliminarily study on the relationship between aflatoxin-producing ability and the genes aflR, omt-1and ver-1 Methods Fungi were isolated by traditional culture method. Potential aflatoxin-producing strains were screened by phenotypic traits and multiplex PCR. After these potential aflatoxin-producing strains cultured in the toxigenic culture medium, the levels of aflatoxin B1 (AFB1) of the cultures were tested with ELISA method. The phylogenetic tree of aflR, omt-1and ver-1 was constructed to explore the relationship between these genes and the AFB1-producing capacity. Results 17 potential aflatoxin-producing fungi were isolated. The ratio of positive toxigenic strains is 64.71%. 11 isolates were positive in AFB1 detection while existing high sequence homology with AS 3.4408, 6 isolates were negative in AFB1 detection while existing high sequence homology with Aspergillus oryzae. Conclusion Aspergillus flavusare potential candidates for aflatoxin control. Not all Aspergillus flavus have AFB1-producing capacity, AflR gene had a direct relation to AFB1-producing capacity, while ver-1 and omt-1were related to the level of AFB1 producing.

     

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