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Fungi can intervene in hosts' brain function. In humans, they can drive neuroinflammation, neurodegenerative diseases and psychiatric disorders. However, how fungi alter the host brain is unknown. The mechanism underlying innate immunity to fungi is well-known and universally conserved downstream of shared Toll/TLR receptors, which via the adaptor MyD88 and the transcription factor Dif/NFκB, induce the expression of antimicrobial peptides (AMPs). However, in the brain, Toll-1 could also drive an alternative pathway via Sarm, which causes cell death instead. Sarm is the universal inhibitor of MyD88 and could drive immune evasion. Here, we show that exposure to the fungus Beauveria bassiana reduced fly life span, impaired locomotion and caused neurodegeneration. Beauveria bassiana entered the Drosophila brain and induced the up-regulation of AMPs, and the Toll adaptors wek and sarm, within the brain. RNAi knockdown of Toll-1, wek or sarm concomitantly with infection prevented B. bassiana-induced cell loss. By contrast, over-expression of wek or sarm was sufficient to cause neuronal loss in the absence of infection. Thus, B. bassiana caused cell loss in the host brain via Toll-1/Wek/Sarm signalling driving immune evasion. A similar activation of Sarm downstream of TLRs upon fungal infections could underlie psychiatric and neurodegenerative diseases in humans. This study identifies a new step in the evolutionary arms race between host and fungus in the Drosophila brain. The fungus B. bassiana exploits the Toll-1 host response to activate the MyD88 inhibitor Sarm, enabling immune evasion and triggering neurodegeneration. [ABSTRACT FROM AUTHOR]

White-rot fungi are efficient organisms for the mineralization of lignin and polysaccharides into CO2 and H2O. Despite their biotechnological potential, WRF metabolism remains underexplored. Building on recent findings regarding the utilization of lignin-related aromatic compounds as carbon sources by WRF, we aimed to gain further insights into these catabolic processes. For this purpose, Trametes versicolor and Gelatoporia subvermispora were incubated in varying conditions – in static and agitation modes and different antioxidant levels – during the conversion of 4-hydroxybenzoic acid (a lignin-related compound) and cellobiose. Their metabolic responses were assessed via transcriptomics, proteomics, lipidomics, metabolomics, and microscopy analyses. These analyses reveal the significant impact of cultivation conditions on sugar and aromatic catabolic pathways, as well as lipid composition of the fungal mycelia. Additionally, this study identifies biosynthetic pathways for the production of extracellular fatty acids and phenylpropanoids – both products with relevance in biotechnological applications – and provides insights into carbon fate in nature. Cultivation of white-rot fungi in distinct incubation conditions and in the presence of a lignin-related aromatic compound induces significant metabolic changes on aromatic catabolic pathways in the transcriptome, proteome, lipidome, and metabolome. [ABSTRACT FROM AUTHOR]

Simple Summary: Phenotypic plasticity describes the ability of one genotype to produce different phenotypes in response to variable environments. The oriental armyworm, Mythimna separata, exhibits phenotypic plasticity in response to changes in population density. Solitary and gregarious phases occur at low and high larval densities, respectively, and lead to morphological, behavioral, and physiological differences. Gregarious larvae generally exhibit a darker body color, but differences in integument ultrastructure and gene expression in the two phases of M. separata are largely unknown. In this study, we compared both ultrastructure and differentially expressed genes in the integument of the two larval phases and verified the relevant results. We discovered that gregarious larvae had thicker integuments and more polygonal particles on the cuticle surface than solitary larvae. Many differentially expressed genes were identified relevant to fatty acid synthesis, integument structure, and insecticide detoxification. Our findings provide a valuable resource for understanding the mechanistic basis of behavioral and physiological differences in the two phases of M. separata. Mythimna separata larvae exhibit both solitary and gregarious phases under low and high population density, respectively; furthermore, differences in morphology, behavior and physiology have been observed in the two phases. The integument plays an essential role in the fitness, general metabolism, communication, and survival of insects; however, differences in the integument ultrastructure and gene expression in the solitary and gregarious phases are largely unknown. In this study, the integument ultrastructure of larvae in the solitary and gregarious phases was compared, and transcriptome analysis was conducted to identify which genes were differentially expressed in the two phases. The results showed that the gregarious larvae had thicker integuments and more polygonal particles on the cuticle surface than solitary larvae. Using the Illumina HiSeq™ sequencing platform, 2774 differentially expressed genes (DEGs) were generated. Among these, many transcripts were identified with roles in the synthesis of fatty acids; structural components of the integument and the insecticide detoxification were differentially expressed in the integument of the two larval phases. qRT-PCR was used to validate expression patterns of the selected transcripts. This study provides a valuable resource for understanding the molecular basis of behavioral and physiological differences in the two phases of M. separata. [ABSTRACT FROM AUTHOR]