Recurrent loss ofabaA, a master regulator of asexual development in filamentous fungi, correlates with changes in genomic and morphological traits

Abstract

Author Summary 46Fungi exhibit tremendous variation in their asexual fruiting bodies. For example, whereas some 47 fungi form complex fruiting bodies whose tips repeatedly generate and release spores, others 48 produce single spores in the absence of a specialized structure. To gain insights into the 49 molecular differences that underpin fungal asexual fruiting body diversity, we examined the 50 genomes of hundreds of filamentous fungi for the presence of abaA, a master regulatory gene 51 previously shown to control the development of fungal asexual fruiting bodies. We found that 52 abaA was repeatedly lost during fungal evolution, including in a lineage of human pathogenic 53 fungi, and that the loss of the gene was always associated with the loss of specialized structures 54 in fungal asexual fruiting bodies. Reintroduction of abaA into the human pathogenic fungus 55Histoplasma capsulatum, which normally lacks the regulator, did not result in a change in the 56 spore-producing structure but did increase spore outgrowth. Based on these results, we 57 hypothesize that the loss of the master regulatory gene abaA has contributed to the observed 58 diversity of fungal fruiting body morphology. This work advances our understanding of how 59 fungal developmental networks evolve over time and advances our understanding of how 60 infectious spores form in pathogenic fungi. 61

The PHD transcription factor Cti6 is involved in the fungal colonization and aflatoxin B1 biological synthesis of Aspergillus flavus

“…2 and 5 ). BrlA and AbaA are two key DNA-binding transcriptional factors in regulation of asexual proliferation, in which BrlA initiates the program, and AbaA activates the development of the phialides in conidiophores (the asexual fruiting bodies) of filamentous fungi (Mead et al 2020 ; Sewall 1994 ). By deletion of PHD and Atrophin-1 domain, it was found that, similar to Δ cti6 , the fungal colony size, mycelial density and conidiation state of PHD domain deletion strain ( cti6 ΔPHD ) on both PDA media and crop kernels were significantly restrained compared to the Ctrl fungal strain, but Atrophin-1 domain was only involved in the sporulation of the fungus (Figs.…”

Transcription factors in the fungus Aspergillus nidulans: Markers of genetic innovation, network rewiring and conflict between genomics and transcriptomics

“…Knowledge thus gained can, of course, be extended to other fungal systems. Recently, new experimental approaches have been developed, focused on the expression of genes encoding regulators of A. nidulans asexual reproduction with the aim of modifying developmental patterns of species such as Monascus ruber or Histoplasma capsulatum (Ojeda-López et al 2018;Mead et al 2020). Although the trials were unable to trigger major morphological changes, they paved the way for the establishment of simple and reliable approaches for the experimental study of GRN rewiring and its consequences on organism evolution.…”