Cyclic AMP-dependent protein kinase is involved in morphogenesis of Aspergillus niger.
The cAMP signal transduction pathway controls many processes in fungi. The pkaR gene, encoding the regulatory subunit (PKA-R) of cAMP-dependent protein kinase (PKA), was cloned from the industrially important filamentous fungus Aspergillus niger. To investigate the involvement of PKA in morphology of A. niger, a set of transformants which overexpressed pkaR or pkaC (encoding the catalytic subunit of PKA) either individually or simultaneously was prepared as well as mutants in which pkaR and/or pkaC were disrupted. Strains overexpressing pkaR or both pkaC and pkaR could not be distinguished from the wild-type, suggesting that regulation of PKA activity is normal in these strains. Absence of PKA activity resulted in a two- to threefold reduction in colony diameter on plates. The most severe phenotype was observed in the absence of PKA-R, i.e., very small colonies on plates, absence of sporulation and complete loss of growth polarity during submerged growth. Suppressor mutations easily developed in the DeltapkaR mutant and one of these mutants appeared to lack PKA-C activity. These data suggest that cAMP-dependent protein phosphorylation in A. niger regulates growth polarity and formation of conidiospores.
Saudohar
Mojca
M
National Institute of Chemistry, Department for Biotechnology and Industrial Mycology, Hajdrihova 19, SI-1000 Ljubljana, Slovenia1.
Bencina
Mojca
M
National Institute of Chemistry, Department for Biotechnology and Industrial Mycology, Hajdrihova 19, SI-1000 Ljubljana, Slovenia1.
van de Vondervoort
Peter J I
PJI
Wageningen University, Section Molecular Genetics of Industrial Micro-organisms, Dreijenlaan 2, 6703HA Wageningen, The Netherlands2.
Panneman
Henk
H
Wageningen University, Section Molecular Genetics of Industrial Micro-organisms, Dreijenlaan 2, 6703HA Wageningen, The Netherlands2.
Legisa
Matic
M
National Institute of Chemistry, Department for Biotechnology and Industrial Mycology, Hajdrihova 19, SI-1000 Ljubljana, Slovenia1.
Visser
Jaap
J
Wageningen University, Section Molecular Genetics of Industrial Micro-organisms, Dreijenlaan 2, 6703HA Wageningen, The Netherlands2.
Ruijter
George J G
GJG
Wageningen University, Section Molecular Genetics of Industrial Micro-organisms, Dreijenlaan 2, 6703HA Wageningen, The Netherlands2.
D001234:Aspergillus niger / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D015152:Blotting, Northern; D017868:Cyclic AMP-Dependent Protein Kinases / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D015966:Gene Expression Regulation, Fungal; D008969:Molecular Sequence Data; D009024:Morphogenesis / Q000502:physiology; D015398:Signal Transduction; D013172:Spores, Fungal / Q000502:physiology; D014170:Transformation, Genetic
D017868:Cyclic AMP-Dependent Protein Kinases