Comparative profiling of phenolic compounds in callus cultures of Fagopyrum spp.: insights into F. esculentum, F. tataricum, and F. homotropicum

Abstract The genus Fagopyrum includes economically important species such as F. esculentum and F. tataricum , which are valued for their nutritional and bioactive properties, as well as their wild relative F. homotropicum , which is understudied in tissue culture systems. While callus cultures of Fagopyrum species are essential for breeding and biotechnology applications, their growth and metabolic dynamics are poorly characterised, particularly regarding phenolic compound accumulation, which can influence callus proliferation and regeneration. This study aims to provide a comparative analysis of callus growth kinetics, phenolic metabolism, and gene expression in F. esculentum , F. tataricum , and F. homotropicum . Callus growth varied significantly among the three species, with F. esculentum exhibiting the highest proliferation rate, with an increase of 11.4-fold of its initial mass, followed by F. tataricum with a 4.7-fold increase and F. homotropicum with a 3.5-fold increase. Phenolic profiling revealed distinct metabolic specialisations: F. homotropicum exhibited the highest total phenolic content, primarily dominated by flavan-3-ols, such as (+)-catechin (3207.98 µg/g). In contrast, F. tataricum predominantly accumulated rutin (1331.63 µg/g), while F. esculentum displayed the minimal total phenolics content. Corresponding gene expression patterns aligned with these trends, as F. homotropicum strongly upregulated dihydroflavonol 4-reductase (proanthocyanidin synthesis), whereas F. tataricum favoured flavonol synthase expression, consistent with its rutin-rich profile. This study establishes a foundation for optimising Fagopyrum tissue culture systems and elucidates species-specific metabolic adaptations, advancing their potential use in biotechnology and breeding programs. Graphical abstract