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The acetylation of histone lysine residues regulates multiple life processes, including growth, conidiation, and pathogenicity in filamentous pathogenic fungi. However, the specific function of each lysine residue at the N-terminus of histone H3 in phytopathogenic fungi remains unclear. In this study, we mutated the N-terminal lysine residues of histone H3 in Fusarium pseudograminearum, the main causal agent of Fusarium crown rot of wheat in China, which also produces deoxynivalenol (DON) toxins harmful to humans and animals. Our findings reveal that all the FpH3K9R, FpH3K14R, FpH3K18R, and FpH3K23R mutants are vital for vegetative growth and conidiation. Additionally, FpH3K14 regulates the pathogen's sensitivity to various stresses and fungicides. Despite the slowed growth of the FpH3K9R and FpH3K23R mutants, their pathogenicity towards wheat stems and heads remains unchanged. However, the FpH3K9R mutant produces more DON. Furthermore, the FpH3K14R and FpH3K18R mutants exhibit significantly reduced virulence, with the FpH3K18R mutant producing minimal DON. In the FpH3K9R, FpH3K14R, FpH3K18R, and FpH3K23R mutants, there are 1863, 1400, 1688, and 1806 downregulated genes, respectively, compared to the wild type. These downregulated genes include many that are crucial for growth, conidiation, pathogenicity, and DON production, as well as some essential genes. Gene ontology (GO) enrichment analysis indicates that genes downregulated in the FpH3K14R and FpH3K18R mutants are enriched for ribosome biogenesis, rRNA processing, and rRNA metabolic process. This suggests that the translation machinery is abnormal in the FpH3K14R and FpH3K18R mutants. Overall, our findings suggest that H3 N-terminal lysine residues are involved in regulating the expression of genes with important functions and are critical for fungal development and pathogenicity. [ABSTRACT FROM AUTHOR]

Root rot is a serious disease of garlic in the Shandong Province of China. Infected plants display symptoms such as dwarfed garlic bulbs, yellowing of leaves starting from the periole, discoloration of the basal stem, and rot. The aim of this study was the identification of the main pathogens involved in garlic root rot. Fifty garlic plants with root rot were collected from the five main production areas of garlic in the Shandong Province. Isolates was incubated using selective medium and identified using morphological method and the ribosomal DNA internal transcribed spacer (ITS) sequence alignment, followed by the confirmation of pathogenicity and the identification of biological characteristics of the putative pathogens. The isolation frequency of Pythium isolated from garlic root was 45%, resulting in a total of 12 isolates. According to morphological identification and ITS sequence alignment, the 12 isolates were further identified as Pythium sylvaticum Compbell & Hendrix, Pythium heterothallicum Compbell & Hendrix, Pythium paroecandrum Drechsler, and Pythium violae Chesters & Hickman. All 12 isolates were pathogenic when inoculated on the root collar and roots of garlic plants. The optimal temperature of Pythium growth was 20–25 °C and pH was 6–7. Pythium sylvaticum, Pythium heterothallicum, Pythium paroecandrum, Pythium violae, and Pythium sp. 845 us-2 were identified as causal agents of garlic root rot. [ABSTRACT FROM AUTHOR]