Abstract Detail

Poster Session

Zhang, Jiwei [1], Presley, Gerald  [1], Song, Zewei [1], Oliver, Jason P. [2], Schilling, Jonathan S. [1].

Partitioning transcriptions of the oxidative enzymes and cellulase reveals the spatially control mechanisms of fungi during wood degradation.

Lignocellulose polymers degradation by fungi plays critical roles in the global carbon source cycling. Oxidative pretreatment along with cellulase sacchrification have been generally believed as the major mechanisms during lignocellulose degradation by wood-degrading fungi, practically in white-rot and brown-rot. However, the relationships between these two treatment ways and the associated molecular events are rarely known till now. Using brown-rot fungi Postia placenta as the model and the spatially fungal colonized spruce wafer design, our previous work found that hyphal fronts and apparent depolymerization are ahead of the cellulase secretion. To further explore the molecular mechanisms of the spatial distribution between pretreatments and cellulase saccharification, the transcriptions of three target genes, cel5B encoding one of the major endoglucanases, aox1 representing a putative enzyme producing hydroxide and ord1 encoding the quinone reductase that likely plays a critical role in quinone redox cycling and iron reduction, were detected in the P. placenta from colonized spruce wafer. Here, the hydroxide and the iron reduction are considered as the basis for producing hydroxyl radicals which have been believed to contribute to the pretreatment of brown- or white rot fungi. Correlated with the previous physiochemical results, the expression of ord1 and aox1 occur in the leading zone of the colonization and precede cel5B by about 15 cm and 20 cm respectively, indicating the oxidation pretreatment might be separated from the cellulase-driving hydrolysis through adjusting the transcriptions of associated genes. Together, our findings provide the molecular evidence that oxidation works as the incipient reaction followed by cellulase function during wood degradation by fungi.

1 - University of Minnesota, Department of Bioproducts and Biosystems Engineering , Kaufert Lab - 2004 Folwell Ave, Saint Paul, MN, 55108, USA
2 - University of Minnesota, Department of Bioproducts and Biosystems Engineering, Kaufert Laboratory, 2004 Folwell Avenue, Saint Paul, MN, 55108, USA

Keywords:
partitioning transcriptions
oxidation pretreatment
cellulase
wood decay mechanism.

Presentation Type: Offered Paper - Poster
Session: P4
Location: Lincoln Room/Kellogg Hotel and Conference Center
Date: Tuesday, June 10th, 2014
Time: 8:00 PM
Number: P4003
Abstract ID:162
Candidate for Awards:None