Fig. 5

Clustering analysis of enriched cell functions related to isobutanol stress and tryptophan supplementation. The expression changes between each sample pair were subject to enrichment analysis. The enriched cellular functions were then clustered to exhibit the gene expression pattern differences between the high and low expression levels in each sample, which were represented by red and blue color, respectively. The enriched cell functions include: a biosynthesis of amino acids, b amino acid transporters, c the pentose phosphate pathway, d tryptophan metabolism, e nicotinate and nicotinamide metabolism, f vitamin B₆ metabolism, g thiamine (vitamin B₁) metabolism, and h fatty acid metabolism. The rectangle emphasizes the gene clusters related to isobutanol stress and tryptophan. The number to the right-hand side represents every single gene applied to each heatmap. Gene names of each heatmap are listed in Additional file 1: Table S3