Poster: Genomic & proteomic resources

Abs # 895: Growth transition from glucose to pectin and starved conditions in Aspergillus nidulans

Presenter:	Ray, Anamika , aray@biochem.okstate.edu
Authors	Ray, Anamika  (A)   Ayoubi, Patricia  (A)   Prade, Rolf  (A)   Mort, Andrew J. (A)
Affiliations:	(A): Oklahoma State University

Although saprophytic fungi are capable of growth on dead plant material they preferentially use glucose as a carbon source (carbon catabolite repression). We are taking a genomics approach to survey the changes in transcription that take place in Aspergillus nidulans when its carbon source is switched from glucose to plant polysaccharides. We devised in Aspergillus nidulans a Negative Subtraction Hybridization (NSH) method to isolate differentially expressed cDNAs. After a screen for transcripts induced by plant polysaccharides 3,532 clones were isolated, end-sequenced, and assembled into 2,039 contigs, of which 1,722 were not present in a previously characterized glucose-grown conidiating cDNA library of A. nidulans (12,320 ESTs). The isolated clones were PCR amplified and spotted on glass slides for microarray analysis. The microarrays will be used to study the changes in gene expression following the transition from glucose to pectin (inducer) and from glucose to starved conditions (release from catabolite repression) at different times after the switch. This will help us to identify the genes required for growth on a particular complex polysaccharide and will define the mode of genetic regulation due to substrate specific induction and derepression (absence of glucose).