title: Effect of cell wall integrity stress and RlmA transcription factor on asexual development and autolysis in Aspergillus nidulans.
abstract: The cell wall integrity (CWI) signaling pathway is responsible for cell wall remodeling and reinforcement upon cell wall stress, which is proposed to be universal in fungal cultures. In Aspergillus nidulans, both the deletion of rlmA encoding the RlmA transcription factor in CWI signaling and low concentrations of the cell wall polymer intercalating agent Congo Red caused significant physiological changes. The gene deletion mutant ΔrlmA strain showed decreased CWI and oxidative stress resistances, which indicated the connection between the CWI pathway and the oxidative stress response system. The Congo Red stress resulted in alterations in the cell wall polymer composition in submerged cultures due to the induction of the biosynthesis of the alkali soluble fraction as well as the hydrolysis of cell wall biopolymers. Both RlmA and RlmA-independent factors induced by Congo Red stress regulated the expression of glucanase (ANID_00245, engA) and chitinase (chiB, chiA) genes, which promoted the autolysis of the cultures and also modulated the pellet sizes. CWI stress and rlmA deletion affected the expression of brlA encoding the early conidiophore development regulator transcription factor BrlA and, as a consequence, the formation of conidiophores was significantly changed in submerged cultures. Interestingly, the number of conidiospores increased in surface cultures of the ΔrlmA strain. The in silico analysis of genes putatively regulated by RlmA and the CWI transcription factors AnSwi4/AnSwi6 in the SBF complex revealed only a few jointly regulated genes, including ugmA and srrA coding for UgmA UDP-galactopyranose mutase and SrrA stress response regulator, respectively.
authors.affiliation: Department of Microbial Biotechnology and Cell Biology, Faculty of Science and Technology, University of Debrecen, H-4010 Debrecen, Hungary.
authors.forename: Zsuzsanna
authors.initials: Z
authors.lastname: Kovács
authors.forename: Máté
authors.initials: M
authors.lastname: Szarka
authors.forename: Szilvia
authors.initials: S
authors.lastname: Kovács
authors.forename: Imre
authors.initials: I
authors.lastname: Boczonádi
authors.forename: Tamás
authors.initials: T
authors.lastname: Emri
authors.forename: Keietsu
authors.initials: K
authors.lastname: Abe
authors.forename: István
authors.initials: I
authors.lastname: Pócsi
authors.forename: Tünde
authors.initials: T
authors.lastname: Pusztahelyi
mesh_terms: D001233:Aspergillus nidulans / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development*; D001329:Autolysis / Q000235:genetics; D002473:Cell Wall / Q000235:genetics* / Q000378:metabolism; D002688:Chitinases / Q000235:genetics / Q000378:metabolism; D003224:Congo Red / Q000633:toxicity; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal; D012100:Reproduction, Asexual / Q000235:genetics* / Q000502:physiology; D015398:Signal Transduction; D013312:Stress, Physiological; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D005656:Fungal Proteins; D014157:Transcription Factors; D003224:Congo Red; D002688:Chitinases