Department of Plant Pathology, Iowa State University, Ames, IA, USA.
Food Addit Contam Part A Chem Anal Control Expo Risk Assess. 2009 Mar;26(3):388-94. doi: 10.1080/02652030802471239.
Fusarium subglutinans (teleomorph Gibberella subglutinans, member of the Gibberella fujikuroi complex) is an important toxigenic pathogen of maize. Recently, two cryptic species (Groups 1 and 2) have been described within F. subglutinans, but little is known about the occurrence of the two groups in North America or their relative capacities to produce mycotoxins. In this study, 58 F. subglutinans strains from kernels of maize grown in Iowa, USA, were evaluated for cryptic speciation and production of the mycotoxins fusaproliferin and beauvericin. Fifty-six of the 58 strains (97%) belonged to Group 2, and two strains belonged to Group 1, based on restricted fragment length polymorphisms derived from amplification of histone H3 and beta-tubulin gene fragments. Fifty-four Group 2 strains and both Group 1 strains produced fusaproliferin at concentrations ranging from 12 to 3000 microg g(-1) of solid maize culture. None of the F. subglutinans strains from Iowa produced beauvericin at detectable amounts, although most F. subglutinans strains from Europe and elsewhere are beauvericin producers. These results indicate that F. subglutinans strains infecting maize kernels in Iowa belong almost exclusively to Group 2 and that they have a high potential for fusaproliferin production; furthermore, the results confirm an association between Group 2 genotypes and lack of beauvericin production. This is the first report characterizing the phylogenetic groups of F. subglutinans occurring in Iowa; the predominance of Group 2 suggests that populations of the fungus in Iowa and Europe remain isolated from each other. Fusaproliferin contamination of grain appears to be a risk wherever F. subglutinans occurs, but beauvericin contamination from F. subglutinans is associated only with Group 1.
玉米平脐蠕孢（有性态为藤仓赤霉 Gibberella subglutinans，属于藤仓赤霉菌复合种）是一种重要的玉米产毒病原菌。最近，在玉米平脐蠕孢内描述了两个隐种（群 1 和群 2），但对它们在北美的发生情况及其产生真菌毒素的相对能力知之甚少。在这项研究中，评估了来自美国爱荷华州玉米穗中的 58 株玉米平脐蠕孢菌株的隐种形成和真菌毒素 Fusaproliferin 和 Beauvericin 的产生情况。根据从组蛋白 H3 和β-微管蛋白基因片段扩增得到的限制性片段长度多态性，58 株菌株中的 56 株（97%）属于群 2，有 2 株属于群 1。群 2 的 54 株菌株和群 1 的 2 株菌株均能在固体玉米培养基中产生 Fusaproliferin，浓度范围为 12 至 3000 μg g(-1)。来自爱荷华州的玉米平脐蠕孢菌株均未检测到 Beauvericin 的产生，尽管来自欧洲和其他地区的大多数玉米平脐蠕孢菌株均为 Beauvericin 产生菌。这些结果表明，感染爱荷华州玉米穗的玉米平脐蠕孢菌株几乎完全属于群 2，并且它们具有很高的 Fusaproliferin 产生潜力；此外，结果证实了群 2 基因型与 Beauvericin 产生缺失之间的关联。这是首次描述发生在爱荷华州的玉米平脐蠕孢的系统发育群，群 2 的优势表明，爱荷华州和欧洲的真菌种群彼此隔离。只要玉米平脐蠕孢存在，其对谷物的 Fusaproliferin 污染似乎是一种风险，但只有群 1 的玉米平脐蠕孢才会产生 Beauvericin 污染。
