Fusarium head blight (FHB) is one of the main fungal diseases affecting bread (Triticum aestivum L.) and durum wheat (Triticum durum L.) crops worldwide, resulting not only in important economic losses due to reduced grain yield and quality, but also in grain safety due to mycotoxins contamination, mainly deoxynivalenol (DON). TRI5 gene catalyzes the first step in DON biosynthesis and its expression is used as an indicator for trichothecene synthesis induction. In Argentina, FHB is caused by Fusarium graminearum sensu stricto when humid weather and warm temperature conditions predominate around flowering. Commonly used strategies to manage FHB are not highly efficient if individually applied and under this scenario. Biological control appears as a viable approach than can be included in an integrated FHB management. Previous studies carried out by our research group proved the biocontrol efficacy of Bacillus velezensis RC 218 in reducing FHB in bread and durum wheat, under greenhouse and field conditions. In this study, we analyzed F. graminearum sensu stricto penetration, growth and TRI5 gene expression when B. velezensis RC 218 was applied on wheat spikes. Spike tissue sections were obtained and observed under different microscopic techniques. We observed that the biocontrol agent (BCA) was able to reduce F. graminearum infection and trichothecene accumulation in bread wheat susceptible cultivar BioInta1005. Data on tissue analysis suggest B. velezensis RC 218 induced cell wall thickening in the host tissues immediately surrounding the F. graminearum infection site, preventing cell plasmolysis and collapse.

镰刀枯萎病（Fusarium head blight）（FHB）是影响面包（Triticum aestivum L.）和硬质小麦（Triticum durum L.）作物的主要真菌病之一，不仅由于谷物产量和质量下降而造成重大经济损失，而且还导致由于霉菌毒素污染（主要是脱氧雪腐烯醇（DON））而导致谷物安全性下降。TRI5基因催化DON生物合成的第一步，其表达被用作单端孢菌素合成诱导的指示剂。在阿根廷，FHB是由禾谷镰刀菌引起的在开花期多雨和温暖的温度条件下居多。如果单独应用并且在这种情况下，用于管理FHB的常用策略效率不高。生物控制似乎是一种可行的方法，而不是集成在FHB管理中。我们研究小组进行的先前研究证明，在温室和田间条件下，芽孢杆菌RC 218可以降低面包和硬质小麦的FHB的生物防治功效。在这项研究中，我们分析了B. velezensis时禾谷镰刀菌的严格渗透，生长和TRI5基因表达。RC 218用于小麦穗状花序。获得穗组织切片并在不同的显微镜技术下观察。我们观察到，生物控制剂（BCA）能够减少面包小麦易感品种BioInta1005中的禾本科镰刀菌感染和单端孢菌素积累。组织分析数据表明，velezensis RC 218诱导了紧邻禾谷镰刀菌感染部位的宿主组织中的细胞壁增厚，从而防止了细胞质溶解和塌陷。