Colegio de Postgraduados, Campus Montecillo, Instituto de Fitosanidad, Highway México-Texcoco Km 36.5, Texcoco, State of Mexico 56230, Mexico.
U.S. Department of Agriculture, Agricultural Research Service, 1815 North University Street, Peoria, IL 61604, USA.
Int J Food Microbiol. 2018 May 20;273:11-19. doi: 10.1016/j.ijfoodmicro.2018.03.003. Epub 2018 Mar 13.
Fusarium Head Blight (FHB) is a destructive disease of small grain cereals and a major food safety concern. Epidemics result in substantial yield losses, reduction in crop quality, and contamination of grains with trichothecenes and other mycotoxins. A number of different fusaria can cause FHB, and there are significant regional differences in the occurrence and prevalence of FHB pathogen species and their associated mycotoxins. Information on FHB pathogen and mycotoxin diversity in Mexico has been extremely limited, but is needed to improve disease and mycotoxin control efforts. To address this, we used a combination of DNA sequence-based methods and in-vitro toxin analyses to characterize FHB isolates collected from symptomatic wheat in Mexico during the 2013 and 2014 growing seasons. Among 116 Fusarium isolates, we identified five species complexes including nine named Fusarium species and 30 isolates representing unnamed or potentially novel species. Significant regional differences (P < 0.001) in pathogen composition were observed, with F. boothii accounting for >90% of isolates from the Mixteca region in southern Mexico, whereas F. avenaceum and related members of the F. tricinctum species complex (FTSC) accounted for nearly 75% of isolates from the Highlands region in Central Mexico. F. graminearum, which is the dominant FHB pathogen in other parts of North America, was not present among the isolates from Mexico. F. boothii isolates had the 15-acetyldeoxynivalenol toxin type, and some of the minor FHB species produced trichothecenes, such as nivalenol, T-2 toxin and diacetoxyscirpenol. None of the FTSC isolates tested was able to produce trichothecenes, but many produced chlamydosporol and enniatin B.
镰刀菌顶腐病（FHB）是一种破坏性的小谷物病害，也是一个主要的食品安全问题。疫情导致大量减产、作物质量下降以及谷物中污染三唑醇和其他霉菌毒素。许多不同的镰刀菌都可能导致 FHB，并且 FHB 病原体物种及其相关霉菌毒素的发生和流行在不同地区存在显著差异。有关墨西哥 FHB 病原体和霉菌毒素多样性的信息极为有限，但为了改善疾病和霉菌毒素控制工作，这方面的信息是必需的。为了解决这个问题，我们使用基于 DNA 序列的方法和体外毒素分析相结合，对 2013 年和 2014 年生长季节从墨西哥有症状小麦中收集的 FHB 分离物进行了特征描述。在 116 个镰刀菌分离物中，我们鉴定了五个种复合体，包括九个命名的镰刀菌物种和 30 个代表未命名或潜在新物种的分离物。观察到病原体组成存在显著的地区差异（P<0.001），在墨西哥南部的米斯特克地区，F. boothii 占分离物的 90%以上，而 F. avenaceum 和 F. tricinctum 种复合体（FTSC）的相关成员则占墨西哥中部高地地区分离物的近 75%。在来自墨西哥的分离物中没有发现在北美其他地区占主导地位的 F. graminearum。F. boothii 分离物具有 15-乙酰基脱氧雪腐镰刀菌烯醇毒素类型，一些次要的 FHB 物种产生了霉菌毒素，如雪腐镰刀菌烯醇、T-2 毒素和二乙酰基交链孢酚。测试的 FTSC 分离物均不能产生霉菌毒素，但许多分离物产生了支链孢菌醇和恩镰孢菌素 B。
