Variations in carbon flux allocation among cassava (Manihot esculenta) cultivars arise from balanced competition between starch accumulation and structural component development

ABSTRACT:

Cassava (Manihot esculenta Crantz) storage roots exhibit significant variation in starch content among cultivars, yet the metabolic and molecular mechanisms governing carbon allocation between storage and structural components remain poorly understood. Here, we investigated carbon partitioning in two cassava cultivars with distinct starch phenotypes: high-starch FX01 and low-starch SC16. Using 13C isotope labeling coupled with metabolomic analysis, we traced the pathway of carbohydrates through primary and secondary metabolism. The results revealed that SC16 exhibits enhanced photosynthetic capacity and elevated soluble sugar content in storage roots, whereas FX01 demonstrates superior starch synthesis due to its efficient glucose and fructose phosphorylation. Conversely, SC16 exhibits a faster conversion of 13C-labeled ferulic acid, directing carbon flow towards lignin biosynthesis via the phenylpropanoid pathway. Further, by silencing the MeCOMT8 gene, encoding a key enzyme in ferulic acid biosynthesis, we observed a reduction in lignin content and an increase in ADP-glucose levels in the MeCOMT8-silenced cassava plants, suggesting a regulatory link between these competing pathways. Our research elucidated that the variations in carbon allocation between starch and lignin biosynthesis among different cultivars are finely orchestrated though the specific-step alteration of metabolic flux. These findings provide potential candidate targeted points and valuable insights for high-starch breeding in cassava.

INSTRUMENT(S): Liquid Chromatography MS - negative - reverse-phase, Liquid Chromatography MS - positive - reverse-phase

PROVIDER: MTBLS13541 | MetaboLights | 2025-12-20

REPOSITORIES: MetaboLights