Asexual sporulation signalling regulates autolysis of Aspergillus nidulans via modulating the chitinase ChiB production.
OBJECTIVE
Elucidation of the regulation of ChiB production in Aspergillus nidulans.


RESULTS
Mutational inactivation of the A. nidulans chiB gene resulted in a nonautolytic phenotype. To better understand the mechanisms controlling both developmental progression and fungal autolysis, we examined a range of autolysis-associated parameters in A. nidulans developmental and/or autolytic mutants. Investigation of disorganization of mycelial pellets, loss of biomass, extra-/intracellular chitinase activities, ChiB production and chiB mRNA levels in various cultures revealed that, in submerged cultures, initialization of autolysis and stationary phase-induced ChiB production are intimately coupled, and that both processes are controlled by the FluG-BrlA asexual sporulation regulatory pathway. ChiB production does not affect the progression of apoptotic cell death in the aging A. nidulans cultures.


CONCLUSIONS
The endochitinase ChiB plays an important role in autolysis of A. nidulans, and its production is initiated by FluG-BrlA signalling. Despite the fact that apoptosis is an inseparable part of fungal autolysis, its regulation is independent to FluG-initiated sporulation signalling.


CONCLUSIONS
Deletion of chiB and fluG homologues in industrial filamentous fungal strains may stabilize the hyphal structures in the autolytic phase of growth and limit the release of autolytic hydrolases into the culture medium.
Pócsi
I
I
Department of Microbial Biotechnology and Cell Biology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary. ipocsi@gmail.com
Leiter
E
E
Kwon
N-J
NJ
Shin
K-S
KS
Kwon
G-S
GS
Pusztahelyi
T
T
Emri
T
T
Abuknesha
R A
RA
Price
R G
RG
Yu
J-H
JH
D000908:Antibodies, Fungal / Q000276:immunology; D001233:Aspergillus nidulans / Q000201:enzymology* / Q000235:genetics* / Q000254:growth & development / Q000276:immunology; D001329:Autolysis / Q000235:genetics / Q000378:metabolism; D018533:Biomass; D002686:Chitin / Q000378:metabolism; D002688:Chitinases / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D015966:Gene Expression Regulation, Fungal; D010641:Phenotype; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000235:genetics; D013172:Spores, Fungal / Q000235:genetics / Q000378:metabolism
D000908:Antibodies, Fungal; D005656:Fungal Proteins; D012333:RNA, Messenger; D002686:Chitin; D002688:Chitinases