Ustilaginoidea virens is the causal agent of rice false smut, which has recently become one of the most important rice diseases worldwide. Ustilaginoidins, a major type of mycotoxins produced in false smut balls, greatly deteriorates grain quality. Histone acetylation and deacetylation are involved in regulating secondary metabolism in fungi. However, little is yet known on the functions of histone deacetylases (HDACs) in virulence and mycotoxin biosynthesis in U. virens . Here, we characterized the functions of the HDAC UvHOS3 in U. virens . The Δ Uvhos3 deletion mutant exhibited the phenotypes of retarded growth, increased mycelial branches and reduced conidiation and virulence. The Δ Uvhos3 mutants were more sensitive to sorbitol, sodium dodecyl sulphate and oxidative stress/H ₂ O ₂ . Δ Uvhos3 generated significantly more ustilaginoidins. RNA‐Seq and metabolomics analyses also revealed that UvHOS3 is a key negative player in regulating secondary metabolism, especially mycotoxin biosynthesis. Notably, UvHOS3 mediates deacetylation of H3 and H4 at H3K9, H3K18, H3K27 and H4K8 residues. Chromatin immunoprecipitation assays indicated that UvHOS3 regulates mycotoxin biosynthesis, particularly for ustilaginoidin and sorbicillinoid production, by modulating the acetylation level of H3K18. Collectively, this study deepens the understanding of molecular mechanisms of the HDAC UvHOS3 in regulating virulence and mycotoxin biosynthesis in phytopathogenic fungi.

In this study, an analytical method for the simultaneous determination of the novel insecticide flupyradifurone and its two metabolites in a variety of traditional Chinese herbal medicines was developed for the first time using high-performance liquid chromatography-tandem mass spectrometry. A simple and efficient method using dispersive solid-phase extraction was employed for the pretreatment of the samples. Several extractions and cleanup strategies were evaluated. The recoveries (n=15) of flupyradifurone and its metabolites at three spiking levels were in the range 71.3%101.7%, with corresponding intraday and interday relative standard deviations of 1.1%14.8%. The limits of quantitation were 0.01mg/kg for flupyradifurone and 0.1mg/kg for its two metabolites. Overall, our developed method was sensitive and reliable for the fast screening of flupyradifurone and its two metabolites in traditional Chinese herbal medicine samples.

Ustilaginoidin D is a type of bis-naphtho-γ-pyrone mycotoxin produced by Ustilaginoidea virens, the causal agent of rice false smut. Although previous studies have demonstrated the inhibitory effect of ustilaginoidin D on ATP synthesis and cancer cell growth in mice, its specific health risks remain unclear. Here, we reveal that ustilaginoidin D is highly toxic to mice with an LD₅₀ value of 213 mg /kg·bw. Dose-dependent weight loss and liver damage were observed, accompanied by altered markers of liver cell damage, including the enzyme activities of alanine aminotransferase and aspartate aminotransferase and the content of glutathione in mouse liver. RNA-seq analysis of liver tissues from mice treated with 150 mg of ustilaginoidin D/kg·bw identified significant changes in gene expression profiles, with differentially expressed genes enriched in cancer-related pathways, hypertrophic cardiomyopathy, and metabolic pathways. RT-qPCR data are highly consistent with transcriptome analysis in expression profiles of 22 chemical-carcinogenesis-associated genes. These findings indicate that ustilaginoidin D induces acute toxicity and liver dysfunction in mice, raising serious concerns about its threat to human health.

Tomatoes have been widely planted in greenhouses and fields in China. Soil-borne diseases are more harmful to tomatoes than other types of diseases. Dimethyl disulfide (DMDS) was used as a novel fumigant instead of methyl bromide to control soil-borne diseases. To assess the safety of DMDS for use on tomatoes, its dissipation and terminal residues were investigated at three different locations under greenhouse and open field conditions. The QuEChERS method was simplified using gas chromatography with mass spectrometry detection and combined with liquid-liquid extraction purification to allow determination of DMDS levels in both the tomatoes and the soil. The average recovery of the method was between 85.3 and 98.6%, with the relative standard deviation (RSD) ranging from to 1.9–10.3%. The dissipation and terminal residues of DMDS in the tomatoes and the soil were analyzed using the method, the results of which showed that the half-life of DMDS ranged from 0.3–6.5 d in the soil at three different locations. The terminal residues of DMDS in the tomatoes and the soil were not detected. This study provided data that the Chinese government can use to support appropriate and safe guidance for the use of DMDS on agriculture.

Agave triangularis Jacobi is an ornamental agave species that represents a valuable genetic resource for enhancing resistance and tolerance in cultivated agaves such as A. tequilana and A. H11648. In this study, we performed the first de novo transcriptome assembly of A. triangularis using Illumina sequencing. A total of 131,321 transcripts were assembled, comprising 119,764,849 bp. Functional annotation revealed a close evolutionary relationship between A. triangularis and Asparagus officinalis, supporting its phylogenetic placement within the Asparagaceae family. We further identified five SRO genes in both A. triangularis and A. H11648. Their expression profiles in A. H11648, analyzed by qRT-PCR, suggested involvement in leaf development. Notably, AhSRO2 and AhSRO3 were significantly up-regulated following oomycete infection, while AhSRO3 was markedly induced under low-temperature stress. These findings highlight AhSRO2 and AhSRO3 as promising candidate genes for further functional investigation. This study provides the first reference transcriptome for A. triangularis, offering a valuable resource for gene discovery and comparative evolutionary studies in agave. The expression patterns of SRO genes establish a framework for understanding their potential roles in leaf development and stress responses, supporting future efforts toward genetic improvement in agave species.