Effects of early transplanting and topping on glycolysis in the upper leaves of Nicotiana tabacum

Abstract

The timing of transplanting and topping significantly affects transcriptional expression, thereby influencing the metabolic and developmental processes of tobacco. The glycolysis pathway plays a central role in driving internal chemical changes that shape alterations in the tobacco's metabolic pathways. Transcriptome analysis revealed that early transplanting and topping treatments resulted in 4,534 differentially expressed genes. KEGG annotation identified 32 differentially expressed genes associated with glycolysis metabolism. Specifically, the aldehyde dehydrogenase (NAD(+)) (EC 1.2.1.3) pathway was significantly upregulated, whereas the fructose-bisphosphate aldolase (EC 4.1.2.13) was significantly downregulated. KEGG-GSEA gene set analysis indicated that early transplanting and topping enhanced expression of gene sets involved in glycolysis metabolism. Additionally, two core enrichment genes, KPYC-l and Gal-l, were identified as being involved in glycolysis metabolism. Across the glycolysis metabolic pathway, enzyme activities were predominantly downregulated before phosphoenolpyruvate and upregulated thereafter. This suggests that tobacco likely enhanced phosphoenolpyruvate production through increased activity in the pentose phosphate pathway and gluconeogenesis. These alterations promoted heightened metabolic pathways involving pyruvate, acetate, and acetyl-CoA. A newly identified gene, LOC107803480, belonging to the SCF family, was found to be enriched in glycolysis metabolism according to the KEGG database. This gene contains three conserved motifs: PS00184 (GARS), PS00337 (BETA_LACTAMASE_D), and PS10049 (PSI_RSU). In conclusion, transcriptional analysis and the discovery of novel genes suggest that early transplanting and topping significantly impacts the glycolysis pathway, underscoring its importance in carbohydrate metabolism in tobacco.