Doster Mark A, Cotty Peter J, Michailides Themis J
Department of Plant Pathology, University of California, Davis/Kearney Agricultural Center, Parlier, CA 93648, USA.
Mycopathologia. 2009 Oct;168(4):193-201. doi: 10.1007/s11046-009-9214-8. Epub 2009 May 31.
A new distinctive strain of Aspergillus nomius that produces the potent mycotoxins, aflatoxins, is described from pistachio, pecan, and fig orchards in California. Similar to the typical strain of A. nomius (as represented by the ex-type), the O strain produced both B and G aflatoxins but not cyclopiazonic acid, had similar conidial ornamentation, and grew poorly at 42 degrees C. Furthermore, previous published DNA sequence supports that the new strain is very closely related to the ex-type of A. nomius. However, the O strain differs from the ex-type in several morphological characters. The ex-type was initially described as producing "indeterminate sclerotia" that appear as large (up to 3 mm long) elongated sclerotia on surfaces of media. The O strain produces only small spherical sclerotia (mean diameter <0.3 mm) submerged in the medium. In addition, the O strain has predominantly uniseriate conidial heads, whereas the typical strain of A. nomius has predominantly biseriate heads. The O strain colony color on both Czapek solution agar and Czapek yeast extract agar was more yellowish than the ex-type of A. nomius and other common aflatoxin-producing fungi. Isolates of the O strain reported here from several orchards represent the first report of A. nomius in California.
从加利福尼亚州的开心果、山核桃和无花果果园中发现了一种新型的独特构巢曲霉菌株,该菌株能产生强效霉菌毒素——黄曲霉毒素。与典型的构巢曲霉菌株(以外型菌株为代表)相似,O菌株能产生B型和G型黄曲霉毒素,但不产生环匹阿尼酸,具有相似的分生孢子纹饰,且在42摄氏度下生长不良。此外,先前发表的DNA序列表明,该新菌株与构巢曲霉的外型菌株密切相关。然而,O菌株在几个形态特征上与外型菌株不同。外型菌株最初被描述为产生“不确定菌核”,在培养基表面表现为大型(长达3毫米)的细长菌核。而O菌株只产生浸没在培养基中的小型球形菌核(平均直径<0.3毫米)。此外,O菌株的分生孢子头主要为单列,而典型的构巢曲霉菌株主要为双列。在察氏溶液琼脂和察氏酵母提取物琼脂上,O菌株菌落的颜色比构巢曲霉外型菌株和其他常见的产黄曲霉毒素真菌更偏黄色。本文报道的来自几个果园的O菌株分离物是加利福尼亚州构巢曲霉的首次报道。