Abstract Fungal diseases are aggravating globally in crop cultivation despite of growing inputs of chemical fungicides. Ear rot and fumonisin contamination of kernels caused by Fusarium verticillioides lead to qualitative and quantitative reductions in maize production. In tropical agriculture, high yielding maize currently can only be assured through foliar protection using fungicides due to the high pathogen pressure. However, the use of chemical fungicides alone does not guarantee the protection of kernels. Recently, a tandem application of fungicides with the Bacillus subtilis strain BIOUFLA2 was identified as a promising strategy to control F. verticillioides-caused diseases. We have employed an integrative approach to assess changes in the microbiome of maize subjected to a combination of chemical and biological fungicides and contrasted it to conventional treatments. This was complemented with molecular and analytical monitoring of the pathogen and mycotoxin levels. Two sampling times were included (10 days after application of treatments and upon harvesting) and two maize fields to account for regional differences. A comparative analysis indicated a treatment-specific enrichment of bacterial and fungal OTUs (Operational Taxonomic Units) that were not detectable in the maize microbiome of untreated plants. Both, the chemical and the tandem application of a chemical and biological pesticide resulted in the occurrence of unique OTUs. Samples subjected to these treatments harbored up to 22 additional OTUs. The lowest fumonisin concentration was observed in the treatment that encompassed BIOUFLA2 (field 1 = 0.29 ppm and field 2 = 0.77 ppm), while the conventional fungicide application resulted in the highest mycotoxin concentrations (field 1 = 3.84 ppm and field 2 = 10.02 ppm). Our study provided strong evidence that conventional treatments of maize with fungicides can promote mycotoxin levels in grains and that partial replacement with biologicals can increase the treatment efficiency.

中文翻译：

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微生物组指导评估枯草芽孢杆菌 BIOUFLA2 应用以减少玉米粒中的真菌毒素

摘要 尽管化学杀菌剂的投入不断增加，但全球农作物种植中的真菌病害仍在加剧。Fusarium v​​erticillioides 引起的玉米穗腐病和伏马菌素污染导致玉米产量的质量和数量下降。在热带农业中，由于病原体压力高，目前只能通过使用杀菌剂进行叶面保护来确保高产玉米。然而，单独使用化学杀菌剂并不能保证对籽粒的保护。最近，杀菌剂与枯草芽孢杆菌 BIOUFLA2 菌株的串联应用被确定为控制轮枝杆菌引起的疾病的有希望的策略。我们采用了一种综合方法来评估经过化学和生物杀菌剂组合处理的玉米微生物组的变化，并将其与常规处理进行对比。这与病原体和真菌毒素水平的分子和分析监测相辅相成。包括两个采样时间（施用处理后 10 天和收获后）和两个玉米田以说明区域差异。一项比较分析表明，在未处理植物的玉米微生物组中检测不到细菌和真菌 OTU（操作分类单位）的处理特异性富集。化学和生物农药的化学应用和串联应用都导致了独特的 OTU 的出现。经过这些处理的样品含有多达 22 个额外的 OTU。在包含 BIOUFLA2 的处理中观察到最低的伏马菌素浓度（字段 1 = 0.29 ppm 和字段 2 = 0.77 ppm），而常规杀菌剂应用导致最高的霉菌毒素浓度（字段 1 = 3.84 ppm 和字段 2 = 10.02 ppm） . 我们的研究提供了强有力的证据，表明用杀真菌剂对玉米进行常规处理可以提高谷物中的霉菌毒素水平，部分替代生物制剂可以提高处理效率。