McAlpin C E, Wicklow D T, Platis C E
Bioactive Agents Research Unit, National Center for Agricultural Utilization Research, USDA, Agricultural Research Service, REE, 1815 N. University Street, Peoria, IL 61604.
Plant Dis. 1998 Oct;82(10):1132-1136. doi: 10.1094/PDIS.1998.82.10.1132.
Aspergillus parasiticus was isolated from direct platings of soil from a corn field near Kilbourne, Illinois. Soil contained 0.2 to 4.0 CFU of Aspergillus flavus and/or A. parasiticus per g of soil. Sixty isolates of A. parasiticus, each from a separately collected soil sample, were examined for ability to produce sclerotia and aflatoxins, and were subjected to DNA fingerprinting. PstI digests of total genomic DNA from each isolate were probed using the pAF28 repetitive sequence. Among 60 isolates analyzed, 33 (55%) distinct DNA fingerprint groups were identified (each group sharing less than 80% pAF28 band similarity), including 50 distinct genotypes (83%) with less than 100% pAF28 band similarity. A single A. parasiticus fingerprint group represented 13% of the sample population. The 83% genotypic diversity of the A. parasiticus population was equivalent to the 81% genotypic diversity recorded earlier for a population of 31 A. flavus isolates from the same field soil. Sclerotia were produced by 82% of the 50 A. parasiticus genotypes during dark incubation at 25°C. All isolates of A. parasiticus producedaflatoxin BB and GG, whereas only 36% of the 31 A. flavus isolates from these soils produced aflatoxins.
寄生曲霉是从伊利诺伊州基尔伯恩附近一块玉米地土壤的直接平板培养物中分离得到的。土壤中每克含有0.2至4.0个黄曲霉和/或寄生曲霉的菌落形成单位。对分别从单独采集的土壤样本中分离得到的60株寄生曲霉进行了产菌核和黄曲霉毒素能力的检测，并进行了DNA指纹分析。使用pAF28重复序列对每个分离株的总基因组DNA的PstI酶切产物进行探针杂交。在分析的60株分离株中，鉴定出33个（55%）不同的DNA指纹组（每组pAF28条带相似性低于80%），包括50个不同的基因型（83%），其pAF28条带相似性低于100%。单个寄生曲霉指纹组占样本群体的13%。寄生曲霉群体83%的基因型多样性与之前记录的来自同一田间土壤的31株黄曲霉菌株群体81%的基因型多样性相当。在25°C黑暗培养条件下，50个寄生曲霉菌基因型中的82%产生了菌核。所有寄生曲霉分离株都产生了黄曲霉毒素B1和G1，而这些土壤中的31株黄曲霉菌株中只有36%产生了黄曲霉毒素。
