The role of carbon starvation in the induction of enzymes that degrade plant-derived carbohydrates in Aspergillus niger.
Bottom Line: The up-regulation of the expression of a high number of genes encoding CAZymes that are active on plant-derived carbohydrates during early carbon starvation suggests that these enzymes could be involved in a scouting role during starvation, releasing inducing sugars from complex plant polysaccharides.We show, using proteomics, that carbon-starved cultures indeed release CAZymes with predicted activity on plant polysaccharides.Analysis of the enzymatic activity and the reaction products, indicates that these proteins are enzymes that can degrade various plant polysaccharides to generate both known, as well as potentially new, inducers of CAZymes.
Affiliation: School of Life Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK. Electronic address: email@example.com.Show MeSH
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Mentions: To investigate if the transcript abundance of the autolysis related genes increased during starvation and if the transcript levels of the genes were increased to the same extent on straw as on starvation over time, we followed transcription of 4 genes in time by qRT-PCR with more time-points (12 h and 18 h) than were available for the RNA-Seq study (6 h and 24 h). A subset of genes (chiB, nagA, An07g07700 and brlA) was chosen based on a mixture of patterns in their transcript abundance in the RNA-Seq data (Fig. 3). When measured by qRT-PCR, the increase in transcript abundance (>3-fold increase in expression compared to glucose control and P < 0.05 (Student’s t-test)) in starvation conditions occurred for chiB and brlA after 18 h starvation whereas transcripts for nagA and An07g07700 were already increased at 6 h starvation. The size of the increase in transcripts was generally larger in carbon starvation conditions than in straw conditions (Fig. 3). For example, at the 12 h time-point, chiB, nagA and An07g07700 had 21-fold, 7-fold and 6-fold higher transcript levels respectively during carbon starvation compared to the straw conditions.
Affiliation: School of Life Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK. Electronic address: firstname.lastname@example.org.