The complete nucleotide sequence of putative glucoamylase gene gla1 from the basidiomycetous fungus Lentinula edodes strain L54 is reported. The coding region of the genomic glucoamylase sequence, which is preceded by eukaryotic promoter elements CAAT and TATA, spans 2,076 bp. The gla1 gene sequence codes for a putative polypeptide of 571 amino acids and is interrupted by seven introns. The open reading frame sequence of the gla1 gene shows strong homology with those of other fungal glucoamylase genes and encodes a protein with an N-terminal catalytic domain and a C-terminal starch-binding domain. The similarity between the Gla1 protein and other fungal glucoamylases is from 45 to 61%, with the region of highest conservation found in catalytic domains and starch-binding domains. We compared the kinetics of glucoamylase activity and levels of gene expression in L. edodes strain L54 grown on different carbon sources (glucose, starch, cellulose, and potato extract) and in various developmental stages (mycelium growth, primordium appearance, and fruiting body formation). Quantitative reverse transcription PCR utilizing pairs of primers specific for gla1 gene expression shows that expression of gla1 was induced by starch and increased during the process of fruiting body formation, which indicates that glucoamylases may play an important role in the morphogenesis of the basidiomycetous fungus.Basidiomycetous fungus Lentinula edodes (Berk.) Pegler is the second most widely cultivated mushroom in the world. The cultivation of this fungus makes use of significant amounts of woody polysaccharides, and utilization of the complex polysaccharides is dependent on its ability to synthesize hydrolytic and oxidative enzymes which convert woody polysaccharides into low-molecular-weight compounds that can be absorbed and assimilated for nutrition. Starch is a polymer of glucose and is perhaps, next to cellulose, the most widely available polymeric glucoside made by plants (16,18). Starch is, therefore, available to fungi growing on plants or plant residues. Digestion of starch requires a complex of enzymes. Glucoamylases (1,4-␣-D-glucan glucohydrolases; EC 3.2.1.3) are enzymes that, among others, are believed to be important in the utilization of starch by the basidiomycetous fungus. Glucoamylases are exohydrolases, which catalyze the release of -D-glucose units from the nonreducing ends of amylose, amylopectin, and other polysaccharides (18). Glucoamylase-encoding genes have been cloned from several fungi including Aspergillus awamori (6, 15), Aspergillus niger (1, 3), Aspergillus oryzae (8), Aspergillus terreus (5, 23), and Neurospora crassa (22).Although there have been many reports on glucoamylases in fungi, few studies on the production and regulation of glucoamylases in basidiomycetous fungi have been carried out. El-Zalaki and Hamza (2) studied five basidiomycetous fungus species for their ability to hydrolyze starch. L. edodes was found to be the most promising strain for amylase production. It was also reported that the ...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.