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Fusarium verticillioides is one of the important mycotoxigenic pathogens of maize since it causes severe yield losses and produces fumonisins (FBs) to threaten human and animal health. Previous studies showed that temperature and water activity (a w) are two pivotal environmental factors affecting F. verticillioides growth and FBs production during maize storage. However, the genome-wide transcriptome analysis of differentially expressed genes (DEGs) in F. verticillioides under the stress combinations of temperature and a w has not been studied in detail. In this study, DEGs of F. verticillioides and their related regulatory pathways were analyzed in response to the stress of temperature and a w combinations using RNA-Seq. The results showed that the optimal growth conditions for F. verticillioides were 0.98 a w and 25 °C, whereas the highest per-unit yield of the fumonisin B 1 (FB 1) was observed at 0.98 a w and 15 °C. The RNA-seq analysis showed that 9648 DEGs were affected by temperature regardless of a w levels, whereas only 218 DEGs were affected by a w regardless of temperature variations. Gene Ontology (GO) analysis revealed that a decrease in temperature at both a w levels led to a significant upregulation of genes associated with 24 biological processes, while three biological processes were downregulated. Furthermore, when a w was decreased at both temperatures, seven biological processes were significantly upregulated and four were downregulated. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis revealed that the genes, whose expression was upregulated when the temperature decreased, were predominantly associated with the proteasome pathway, whereas the genes, whose expression was downregulated when the a w decreased, were mainly linked to amino acid metabolism. For the FB 1 , except for the FUM15 gene, the other 15 biosynthetic-related genes were highly expressed at 0.98 a w and 15 °C. In addition, the expression pattern analysis of other biosynthetic genes involved in secondary metabolite production and regulation of fumonisins production was conducted to explore how this fungus responds to the stress combinations of temperature and a w. Overall, this study primarily examines the impact of temperature and a w on the growth of F. verticillioides and its production of FB 1 using transcriptome data. The findings presented here have the potential to contribute to the development of novel strategies for managing fungal diseases and offer valuable insights for preventing fumonisin contamination in food and feed storage. • Higher temperature (25 °C) and higher water activity (0.98 a w) favored the growth of Fusarium verticillioides • Lower temperature (15 °C) and higher water activity (0.98 a w) favored the fumonisin B 1 production in F. verticillioides • Secondary metabolite gene clusters were differentially expressed under temperature/water activity stresses. • The RNA-seq analysis provides gene groups for further investigation of fumonisin biosynthesis in F. verticillioides [ABSTRACT FROM AUTHOR]

Crop loss caused by toxigenic fungi is a standing problem for many cereals worldwide. In this study, structural and physicochemical changes of maize starch after F. verticillioides infection were evaluated. During the colonization, fungi use starch as the carbon source to provide nutrition for their growth and development resulting in the decline of the starch content of maize kernels. The maize starch was severely damaged and many holes were observed on the surface of starch granules when kernels were infected by F. verticillioides. Gel-permeation chromatography (GPC) analysis showed that amylopectin in maize starch was preferentially degraded and the content of amylose was increased. Simultaneously, the onset and peak of gelatinization temperatures of starch after fungal infection were raised. In comparison with native starch, the viscosity and setback value of infected starch was decreased. Furthermore, we found that 2 genes encoded by F. verticilllioides played important roles in starch degradation. [Display omitted] ● Fusarium verticillioides is one of the most important toxigenic fungi of maize. ● Macroscopic structures of maize starch were destroyed by F. verticillioides. ● Fungal infection affected the thermal gelatinization characteristics of cornstarch. ● F. verticillioides secrete starch degrading related enzymes to hydrolyze starch. [ABSTRACT FROM AUTHOR]

Maize ear rot caused by Fusarium graminearum is one of the most severe maize diseases in global maize-growing regions. It reduces maize yield in the field and is also responsible for mycotoxin contamination of grains during the postharvest period. F. graminearum is one of the major deoxynivalenol (DON), nivalenol (NIV), and zearalenone (ZEN) producers. The ingestion of these mycotoxins represents a risk for human and animal health. Hence, early detection and identification of F. graminearum are crucial to controlling these mycotoxins along the food or feed supply chains. In this study, the recombinase polymerase amplification with lateral flow dipstick (RPA-LFD) assay targeting the gao A gene that codes for galactose oxidase was developed. The reaction conditions were optimized to make the method rapid, sensitive, and cost-effective. The developed RPA-LFD assay could detect the presence of 20 fg of the target genomic DNA per reaction within 25 min at 40 °C. Moreover, 52 field samples were tested using the developed RPA-LFD assay and compared with conventional PCR-based methods. The positive rate between RPA-LFD and the conventional PCR-based method was 100%. In conclusion, the developed method provides a novel alternative for the rapid, sensitive, and specific detection and identification of F. graminearum. It is not only workable for bulk maize samples without using sophisticated lab equipment but is also potentially useful for other agriculturally important toxigenic fungi. • Fusarium graminearum is one of the most important toxigenic fungus of cereals and a threat to food and feed production in the world. • A highly specific and cost-effective RPA-LFD assay was developed for rapid detection and identification of F. graminearum in maize. • The RPA-LFD reaction conditions were optimized and as low as 20 fg of target genomic DNA can be detected. • The developed RPA-LFD assays were validated by testing field samples collected from different regions of China. [ABSTRACT FROM AUTHOR]