PcchiB1, encoding a class V chitinase, is affected by PcVelA and PcLaeA, and is responsible for cell wall integrity in Penicillium chrysogenum

Microbiology (Reading). 2011 Nov;157(Pt 11):3036-3048. doi: 10.1099/mic.0.051896-0. Epub 2011 Aug 4.

Abstract

Penicillin production in Penicillium chrysogenum is controlled by PcVelA and PcLaeA, two components of the regulatory velvet-like complex. Comparative microarray analysis with mutants lacking PcVelA or PcLaeA revealed a set of 62 common genes affected by the loss of both components. A downregulated gene in both knockout strains is PcchiB1, potentially encoding a class V chitinase. Under nutrient-depleted conditions, transcript levels of PcchiB1 are strongly upregulated, and the gene product contributes to more than 50 % of extracellular chitinase activity. Functional characterization by generating PcchiB1-disruption strains revealed that PcChiB1 is responsible for cell wall integrity and pellet formation in P. chrysogenum. Further, fluorescence microscopy with a DsRed-labelled chitinase suggests a cell wall association of the protein. An unexpected phenotype occurred when knockout strains were grown on media containing N-acetylglucosamine as the sole C and N source, where, in contrast to the recipient, a penicillin producer strain, the mutants and an ancestral strain show distinct mycelial growth. We discuss the relevance of this class V chitinase for morphology in an industrially important fungus.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Wall / enzymology*
  • Chitinases / genetics
  • Chitinases / metabolism*
  • DNA, Fungal / genetics
  • Fungal Proteins / genetics
  • Fungal Proteins / metabolism*
  • Gene Expression Regulation, Fungal
  • Gene Knockout Techniques
  • Genes, Regulator
  • Mutation
  • Oligonucleotide Array Sequence Analysis
  • Penicillium chrysogenum / enzymology
  • Penicillium chrysogenum / genetics*
  • Penicillium chrysogenum / growth & development
  • Sequence Analysis, DNA

Substances

  • DNA, Fungal
  • Fungal Proteins
  • Chitinases