The beta-1,3-exoglucanase gene exgA (exg1) of Aspergillus oryzae is required to catabolize extracellular glucan, and is induced in growth on a solid surface.
The biological role of ExgA (Exg1), a secretory beta-1,3-exoglucanase of Aspergillus oryzae, and the expression pattern of the exgA (exg1) gene were analyzed. The exgA disruptant and the exgA-overexpressing mutant were constructed, and phenotypes of both mutants were compared. Higher mycelial growth rate and conidiation efficiency were observed for the exgA-overexpressing mutant than for the exgA disruptant when beta-1,3-glucan was supplied as sole carbon source. On the other hand, no difference in phenotype was observed between them in the presence or absence of the inhibitors of cell wall beta-glucan remodeling when grown with glucose. exgA Expression was induced in growth on solid surfaces such as filter membrane and onion inner skin. A combination of poor nutrition and mycelial attachment to a hydrophobic solid surface appears to be an inducing factor for exgA expression. These data suggest that ExgA plays a role in beta-glucan utilization, but is not much involved in cell wall beta-glucan remodeling.
Tamano
Koichi
K
Research Institute for Cell Engineering, National Institute of Advanced Industrial Science and Technology, Ibaraki, Japan.
Satoh
Yuki
Y
Ishii
Tomoko
T
Terabayashi
Yasunobu
Y
Ohtaki
Shinsaku
S
Sano
Motoaki
M
Takahashi
Tadashi
T
Koyama
Yasuji
Y
Mizutani
Osamu
O
Abe
Keietsu
K
Machida
Masayuki
M
D001236:Aspergillus oryzae / Q000201:enzymology* / Q000235:genetics* / Q000254:growth & development; D002473:Cell Wall / Q000737:chemistry / Q000648:ultrastructure; D003470:Culture Media; D018076:DNA, Complementary / Q000096:biosynthesis / Q000235:genetics; D004271:DNA, Fungal / Q000235:genetics; D005374:Filtration; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics / Q000502:physiology; D015966:Gene Expression Regulation, Fungal / Q000235:genetics / Q000502:physiology; D043326:Glucan 1,3-beta-Glucosidase / Q000235:genetics*; D005936:Glucans / Q000378:metabolism*; D025282:Mycelium / Q000201:enzymology / Q000254:growth & development; D009747:Nutritional Physiological Phenomena; D019697:Onions / Q000382:microbiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013499:Surface Properties; D014170:Transformation, Genetic
D003470:Culture Media; D018076:DNA, Complementary; D004271:DNA, Fungal; D005936:Glucans; D043326:Glucan 1,3-beta-Glucosidase; C117648:beta-1,3-exoglucanase