title: Evidence of a critical role for cellodextrin transporte 2 (CDT-2) in both cellulose and hemicellulose degradation and utilization in Neurospora crassa.
abstract: CDT-1 and CDT-2 are two cellodextrin transporters discovered in the filamentous fungus Neurospora crassa. Previous studies focused on characterizing the role of these transporters in only a few conditions, including cellulose degradation, and the function of these two transporters is not yet completely understood. In this study, we show that deletion of cdt-2, but not cdt-1, results in growth defects not only on Avicel but also on xylan. cdt-2 can be highly induced by xylan, and this mutant has a xylodextrin consumption defect. Transcriptomic analysis of the cdt-2 deletion strain on Avicel and xylan showed that major cellulase and hemicellulase genes were significantly down-regulated in the cdt-2 deletion strain and artificial over expression of cdt-2 in N. crassa increased cellulase and hemicellulase production. Together, these data clearly show that CDT-2 plays a critical role in hemicellulose sensing and utilization. This is the first time a sugar transporter has been assigned a function in the hemicellulose degradation pathway. Furthermore, we found that the transcription factor XLR-1 is the major regulator of cdt-2, while cdt-1 is primarily regulated by CLR-1. These results deepen our understanding of the functions of both cellodextrin transporters, particularly for CDT-2. Our study also provides novel insight into the mechanisms for hemicellulose sensing and utilization in N. crassa, and may be applicable to other cellulolytic filamentous fungi.
authors.affiliation: Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.
authors.forename: Pengli
authors.initials: P
authors.lastname: Cai
authors.affiliation: Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.
authors.forename: Ruimeng
authors.initials: R
authors.lastname: Gu
authors.affiliation: Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.
authors.forename: Bang
authors.initials: B
authors.lastname: Wang
authors.affiliation: Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.
authors.forename: Jingen
authors.initials: J
authors.lastname: Li
authors.affiliation: Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.
authors.forename: Li
authors.initials: L
authors.lastname: Wan
authors.affiliation: Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.
authors.forename: Chaoguang
authors.initials: C
authors.lastname: Tian
authors.affiliation: Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China ; Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
authors.forename: Yanhe
authors.initials: Y
authors.lastname: Ma
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002480:Cellulase / Q000235:genetics / Q000378:metabolism; D002482:Cellulose / Q000031:analogs & derivatives* / Q000378:metabolism*; D003912:Dextrins / Q000378:metabolism*; D020869:Gene Expression Profiling; D006026:Glycoside Hydrolases / Q000235:genetics; D059014:High-Throughput Nucleotide Sequencing; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D009492:Neurospora crassa / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D011134:Polysaccharides / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D015415:Biomarkers; D003912:Dextrins; D026901:Membrane Transport Proteins; D011134:Polysaccharides; D012333:RNA, Messenger; C007916:hemicellulose; D002482:Cellulose; C068994:cellodextrin; D006026:Glycoside Hydrolases; C023305:hemicellulase; D002480:Cellulase