Project description:Insect pathogenic fungus Beauveria bassiana in one of the best studied insect biocontrol fungus, which infects insects by cuticle penetration. After breaking the cuticles, the fungus will propagate in insect hemocoel and kill insect hosts. It has also been found that the mycelia of B. bassiana can penetrate plant tissues to reach insect inside plant, e.g. corn borer (Ostrinia furnacalis), but do not cause damage to plants. The mechanism of fungal physiological plasticity is poorly understood. To accompany our genome sequencing work of B. bassiana strain ARSEF 2860, fungal transcriptional responses to different niches were studied using an Illumina RNA_seq technique. To examine fungal response to insect cuticle, conidia were inoculated on locust hind wings for 24 hours before used for RNA extraction. To evaluate fungal adaptation to insect hemocole, the fifth instar larvae of cotton bollworms were injected with spore suspension and fungal cells isolated by centrifugation in a step gradient buffer. To unveil the mechanism of interaction with plants, the fungus was grown in corn root exudates for 24 hours. After RNA sequencing, around three million tags were acquired for each sample and fungal transcriptional profiles were compared.
Project description:Insect pathogenic fungus Beauveria bassiana in one of the best studied insect biocontrol fungus, which infects insects by cuticle penetration. After breaking the cuticles, the fungus will propagate in insect hemocoel and kill insect hosts. It has also been found that the mycelia of B. bassiana can penetrate plant tissues to reach insect inside plant, e.g. corn borer (Ostrinia furnacalis), but do not cause damage to plants. The mechanism of fungal physiological plasticity is poorly understood. To accompany our genome sequencing work of B. bassiana strain ARSEF 2860, fungal transcriptional responses to different niches were studied using an Illumina RNA_seq technique. To examine fungal response to insect cuticle, conidia were inoculated on locust hind wings for 24 hours before used for RNA extraction. To evaluate fungal adaptation to insect hemocole, the fifth instar larvae of cotton bollworms were injected with spore suspension and fungal cells isolated by centrifugation in a step gradient buffer. To unveil the mechanism of interaction with plants, the fungus was grown in corn root exudates for 24 hours. After RNA sequencing, around three million tags were acquired for each sample and fungal transcriptional profiles were compared. Unveiling gene differential expression patterns when the insect biocontrol fungus Beauveria bassiana grown in insect hemocoel, corn root exudates and on insect cuticles.
Project description:Epigenetic modification is important for cellular functions. Trimethylation of histone H3 lysine 4 (H3K4me3), which associates with transcriptional activation, is one of the important epigenetic modifications. In this study, the biological functions of UvKmt2-mediated H3K4me3 modification were characterized in Ustilaginoidea virens, which is the causal agent of the false smut disease, one of the most destructive diseases in rice. Phenotypic analyses of the ΔUvkmt2 mutant revealed that UvKMT2 is necessary for growth, conidiation, secondary spore formation, and virulence in U. virens. RNA-seq analysis demonstrated that UvKmt2-mediated H3K4me3 acts as an important role in transcriptional activation. In particular, H3K4me3 modification involves in the transcriptional regulation of conidiation-related and pathogenic genes. The down-regulation of UvHOG1 and UvPMK1 genes may be one of the main reasons for the reduced pathogenicity and stresses adaptability of the ∆Uvkmt2 mutant. Overall, H3K4me3, established by histone methyltransferase UvKMT2, contributes to fungal development, secondary spore formation, virulence, and various stresses response through transcriptional regulation in U. virens.
Project description:The fungal specific APSES family proteins involve in regulating fungal growth, development, and multiple biological processes. In this study, AoMbp1, an ortholog of Saccharomyces cerevisiae APSES-type transcription factor Mbp1, was functionally analyzed in a representative nematode-trapping fungus Arthrobotrys oligospora. Inactivation of Aombp1 caused a severe affect on the mycelial growth and development, the mycelial growth rate of ∆Aombp1 mutant was remarkably decreased, the hyphal septa were increased whereas the number of nuclei were significantly reduced, and the lipid droplet accumulation was remarkably increased. Meanwhile, the deletion of Aombp1 resulted a considerable reduction in the number of conidiophores and spore yield, which also caused abnormal spore morphology. In addition, the ∆Aombp1 mutants became more sensitive to several chemical stressors, especially to hyperosmotic reagents. Importantly, disruption of Aombp1 caused the number of traps and nematode-trapping ability were significantly reduced, and most of the traps have changed from their original three-dimensional structure to a planar shape. RNA-Seq, DAP-Seq and Y2H assay showed that AoMbp1 interacted with AoSwi6, and involved in regulating cell cycle, meiosis, lipid metabolism, DNA replication, mismatch repair and nucleotide excision repair. Our study elucidated the functions and potential regulatory mechanism of APSES protein Mbp1 in the mycelial development and trap morphogenesis of nematode-trapping fungi.