Transcriptome reveals carbon metabolite biosynthesis profiles related to culm solidification in Phyllostachys...

This study aims to elucidate the mechanisms of carbon metabolism regulation involved in the solidification of bamboo culms in Phyllostachys heteroclada f. solida. Differentially expressed genes (DEGs) between Ph. heteroclada f. solida and hollow-stemmed variant Ph. heteroclada were identified by transcriptome sequencing. Enrichment analysis of GO and KEGG pathways revealed pronounced divergence in starch-sucrose metabolism and phenylpropanoid biosynthesis pathways. Key starch enzyme genes (e.g., PYG and AMY) were downregulated, while genes involved in sucrose metabolism (e.g., INV and SUS) were upregulated in Ph. heteroclada f. solida. Concurrently, lignin biosynthesis genes (e.g., PAL, C4H, and 4CL) were downregulated, whereas genes associated with cell wall synthesis substances such as pectin and cellulose were upregulated. Non-structural carbohydrate accumulation in Ph. heteroclada f. solida was consistent with these gene expression patterns. The study identified key differences in carbon metabolism pathways between Ph. heteroclada f. solida and Ph. heteroclada, demonstrating that the regulation of carbon metabolism genes plays an important role in culm solidification. These findings provide a foundational understanding of the molecular mechanisms underlying bamboo stem variation and offer insights for future bamboo breeding efforts.