RNAseq analysis of the effects of light and the carS mutation in Fusarium fujikuroi and Fusarium oxysporum. RNAseq analysis of the effects of light and the carS mutation in Fusarium fujikuroi and Fusarium oxysporum

In the fungi Fusarium fujikuroi and Fusarium oxysporum, the induction of carotenogenesis by light and its deregulation in carS mutants, affected in a protein of the RING-finger family, are achieved on transcription of the structural genes of the pathway, some of them organized in a cluster. We have carried out global RNAseq transcriptomics analyses to investigate the relationship between the regulatory effects of light and the carS mutation. Either illumination or the absence of a functional carS gene exert wide effects on the transcriptome of F. fujikuroi, with a predominance of activated over repressed genes, and a greater functional diversity in the case of genes induced by light. The number of the latter decreases drastically in the carS mutant, indicating that the deregulation produced by the carS mutation affects the light response of many genes. In addition, light and CarS strongly influence the expression of some genes associated with stress responses. The effects of light and carS mutation on the F. oxysporum transcriptome were partially coincident with those in F. fujikuroi, indicating conservation of the objectives of their regulatory mechanisms. In conclusion, the CarS RING finger protein down-regulates many genes whose expression is up-regulated by light in the wild-type strains of the two Fusarium species investigated, indicating regulatory connections between the control by light and by the CarS protein. Overall design: To check the effect of light in the F. fujikuroi and F. oxysporum transcriptomes we compared dark-grown cultures with parallel cultures exposed for one hour to light. To examine the effect of the carS mutation, in F. fujikuroi we used a formerly investigated carS mutant (SG39), and as an additional control, we used SG256, a stable carS complementing strain (SG256) obtained from SG39 by replacement of the carS mutant allele by a wild type allele. In F. oxysporum, the effect of the carS mutation was inferred from the analysis of two independent carS mutants, SX2 and SX3. Each strain and condition has two independent experimental replicates.