Fig. 6

Relationship between gene expression and methylation (5-methylcytosine) in Populus trichocarpa stems at different developmental stages. a, b, and c Distributions of CG, CHG, and CHH methylation levels, respectively, in various genic regions including 2 kb promoters, gene bodies, and 2 kb downstream regions in primary stems (PS), transitional stems (TS), and secondary stems (SS). The y-axis indicates methylation levels. Methylation levels were partitioned based on gene expression levels. None represents non-expressed genes (FPKM ≤1); Low represents minimally expressed genes (1 < FPKM ≤10); Moderate represents moderately expressed genes (10 < FPKM ≤100); and High represents highly expressed genes (FPKM ≥100)