Cellodextrin transporters play important roles in cellulase induction in the cellulolytic fungus Penicillium oxalicum

Abstract

Cellodextrin transporters (cellodextrin permeases) have been identified in fungi in recent years. However, the functions of these transporters in cellulose utilization and cellulase expression have not been well studied. In this study, three cellodextrin transporters, namely, CdtC, CdtD, and CdtG, in the cellulolytic fungus Penicillium oxalicum (formally was classified as P. decumbens) were identified, and their functions were analyzed. The deletion of a single cellodextrin transporter gene slightly decreased cellobiose consumption, but no observable effect on cellulase expression was observed, which was attributed to the overlapping activity of isozymes. Further simultaneous deletion of cdtC and cdtD resulted in significantly decreased cellobiose consumption and poor growth on cellulose. The extracellular activity and transcription level of cellulases in the mutant without cdtC and cdtD were significantly lower than those in the wild-type strain when grown on cellulose. This result provides direct evidence of the crucial function of cellodextrin transporters in the induction of cellulase expression by insoluble cellulose.

Genome sequencing and analysis of Talaromyces pinophilus provide insights into biotechnological applications

“…Among the EPTs, 431 members of a major facilitator superfamily were selected; these are involved in the transport of substances including sugar, drugs and peptides. Of these EPTs, TP13272 and TP06909, respectively, were orthologs of the cellodextrin transporters Cdt-C and Cdt-D, which are crucial for induction of cellulase gene expression by insoluble cellulose 31 .…”

The Putative Cellodextrin Transporter-like Protein CLP1 Is Involved in Cellulase Induction in Neurospora crassa

“…Besides the ␤-glucosidase, cellodextrin transporters are also involved in the cellulose degradation and cellulase induction pathway because of their ability to transport a putative inducer of cellulase in N. crassa, cellobiose (2). The roles of cellodextrin transporters in the cellulase induction pathway have become an interesting topic recently in N. crassa and other cellulolytic fungi (4,5). Still, very little is known about the whole induction pathway, such as the detailed working roles of each cellodextrin transporter, how they interact with the other components (i.e.…”

“…As yet seven oligosaccharide transporters from filamentous fungi have been shown to be involved in cellulose degradation and cellulase induction, including CDT1 and CDT2 in Neurospora crassa (2,3), Stp1 and Crt1 in Trichoderma reesei (4), and CdtC, CdtD, and CdtG in Penicillium oxalicum (5). CDT1 and CDT2 were the first cellodextrin transporters identified to play an important role in cellulase production and cellulose degradation in N. crassa, especially CDT2.…”

“…In P. oxalicum, CdtC, CdtD, and CdtG can transport cellodextrin. The deletion of cdtC and cdtD decreased cellulase gene expression and caused a growth defect on cellulose medium (5).…”

A paradigm shift in biomass technology from complete to partial cellulose hydrolysis: lessons learned from nature

“…17 New discovery of cellodextrin transporters in cellulolytic fungus Penicillium oxalicum provides additional candidates in the engineering of eukaryotes. 18 In prokaryotes, E. coli's LacY was found to be adequate as a transporter for cellobiose, 10 which was subsequently used to engineer E. coli for cellobiose conversion to lactic acid and meso 2,3-butanediol 19 .…”