Early bolting in Angelica sinensis is frequently accompanied by excessive root lignification, which compromises medicinal quality. However, the enzymatic regulators underlying monolignol flux during this process remain poorly defined. Here, we identify and characterize AsCCR26 , a cinnamoyl-CoA reductase associated with bolting-related lignification in A. sinensis . Comparative transcriptomic analysis of bolting and unbolting roots revealed coordinated activation of phenylpropanoid metabolism and highlighted AsCCR26 as a candidate lignin-pathway gene. Recombinant AsCCR26 efficiently converted multiple hydroxycinnamoyl-CoA substrates, including p -coumaroyl-, caffeoyl-, feruloyl-, and sinapoyl-CoA, indicating broad substrate specificity consistent with a potential role in monolignol biosynthesis. Structure-guided mutagenesis identified four critical residues (T121, Y157, K161, and A198) required for catalytic activity, providing residue-level insight into AsCCR26 function. Constitutive expression of AsCCR26 in Arabidopsis thaliana was associated with increased lignin accumulation and accelerated bolting. In contrast, Agrobacterium -mediated transformation in A. sinensis induced sense-mediated co-suppression of endogenous AsCCR26 , resulting in reduced lignin content and elevated ferulic acid levels, suggesting altered metabolic flux toward monolignol formation. Together, these results suggest that AsCCR26 is associated with flux control in lignin biosynthesis and may contribute to bolting-associated root lignification in A. sinensis . This study provides mechanistic insights into CCR-mediated regulation of phenylpropanoid metabolism and highlights AsCCR26 as a potential target for modulating lignification in medicinal plants.
Li et al. (2026) studied this question.