show Abstracthide AbstractChaetomium globosum is a model of conditional pathogens abundant on a wide variety of substrates in soil, water, and atmosphere environments. Homothallic C. globosum produces hairy perithecia bearing meiotic ascospores that are resistant to harsh conditions for dispersal, and asexual reproduction of conidia has never been observed. RNAs were samples from nine distinct morphological stages during the nearly synchronic perithecial development for C. globosum. Unlike the heterothallic Neurospora crassa, the mating type gene mat a-1 showed comparatively lower expression changes but highly coordinate with expression regulation of mat A-1 in C. globosum. Key regulators, including orthologs of N. crassa sub-1, sub-1 dependent gene NCU00309, and asl-1, in the initiation of sexual development in response to light stimuli, showed similar regulation dynamics between C. globosum and N. crassa. Knockout phenotyping directed by the comparative analysis of transcriptomics between C. globosum and its' closely related Neurospora crassa also suggested some genes that are critical for perithecial development. Among 24 secondary metabolism clusters composed more than 3 genes in C. globosum, 11 showed highly coordinated expression across the perithecial development, and dramatically up-regulation was recorded for all 12 genes in the cochliodones biosynthesis cluster. Up-regulation of chaetoglocin and aureonitol biosynthesis clusters was found to be associated with disturbance in early sexual development and with ascospore maturation. Similar to pathogenic Fusarium graminearum, C. globosum showed coordinately up-regulated expression of homologs of histidine kinases in hyperosmotic response pathways, consist with their ecology adapting to high humidity. Overall design: mRNA were sampled from 9 stages of Chaetomium globosum sexual development, from protoperithecia (0hr), distrubance (2hr), then the other 7 timepoints with a 24hr interval for the perithecial development.