Decifering the mechanisms of aflatoxin formation through functional genomics in Aspergillus flavus

Ref ID: 18257


Jiujiang Yu
, Deepak Bhatnagar
, Thomas E. Cleveland
, Natalie Fedorova
, William C. Nierman
, and Joan W. Bennett

Author address:

USDA/ARS, Southern Regional Research Center.
J. Craig Venter Institute.
Rutgers University.

Full conference title:

Asperfest 9


Sequencing of A. flavus NRRL3357 showed that its 36-Mb genome contains 13,488 genes including predicted 55 secondary
metabolite gene cluster. We sequenced cDNA fragments obtained from Poly(A)-enriched total RNA samples extracted from
mycelium grown under 3 conditions: (i) PMS medium, 30 C, 24h, no toxin; (ii) GMS medium, 30 C, 24h, make toxin; and (iii) GMS
medium, 37 C, 24h, no toxin. Two cDNA libraries from each treatment were sequenced using the Illumina (SOLEXA) short-read
technology. Over 5 Million 100 nt reads were sequenced for each cDNA prep, which were combined to generate a powerful high
resolution map of the A. flavus transcriptome. The analysis detected expression in at least 50 % of the genes for each condition and
contributed to our understanding of the genetic basis of the aflatoxin regulation. This study demonstrates that the aflatoxin pathway
gene cluster consisting of 30 genes are tightly regulated. High temperature turns down aflatoxin gene transcription by turning down
transcription of the two regulatory genes, the aflR and aflS (old name: aflJ). Further, the change in gene expression ratio of aflS to aflR
renders aflR non- functional for activation of aflatoxin pathway gene transcription.

Abstract Number: 2

Conference Year: 2012

Link to conference website: NULL

New link: NULL

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