Carotenoid biosynthesis in the fungus
Fusarium fujikuroi is regulated by environmental factors, with light being the main stimulating signal. The CarS RING-finger protein plays an important role in the downregulation of structural genes of the carotenoid pathway. A recent transcriptomic analysis on the
[...] Read more.
Carotenoid biosynthesis in the fungus
Fusarium fujikuroi is regulated by environmental factors, with light being the main stimulating signal. The CarS RING-finger protein plays an important role in the downregulation of structural genes of the carotenoid pathway. A recent transcriptomic analysis on the effect of
carS mutation identified a gene for a long non-coding RNA (lncRNA) upstream of
carS, called
carP, the deletion of which results in increased
carS mRNA levels and lack of carotenoid production. We have investigated the function of
carP by studying the transcriptomic effect of its deletion and the phenotypes resulting from the reintroduction of
carP to a deletion strain. The RNA-seq data showed that the loss of
carP affected the mRNA levels of hundreds of genes, especially after illumination. Many of these changes appeared to be cascade effects as a result of changes in
carS expression, as suggested by the comparison with differentially expressed genes in a
carS mutant. Carotenoid production only recovered when
carP was integrated upstream of
carS, but not at other genomic locations, indicating a
cis-acting mechanism on
carS. However, some genes hardly affected by CarS were strongly upregulated in the
carP mutant, indicating that
carP may have other regulatory functions as an independent regulatory element.
Full article