Metabolomic and transcriptomic analysis of bitter compounds in Dendrocalamopsis oldhamii shoots

Dendrocalamopsis oldhamii bamboo shoots are an important edible bamboo with a favourable taste and rich nutritional composition. In this study, we aimed to uncover the intricate process behind bitterness formation in Dendrocalamopsis oldhamii bamboo shoots, which significantly impacts their nutritional quality and economic worth upon being unearthed. Employing a combination of metabolomic and transcriptomic analyses, we scrutinized both underground (DoS) and unearthed (DoB) shoots. The metabolomic assessment unveiled 1017 secondary metabolites, with 151 potentially linked to bitterness based on BitterDB and literature references. Through integrated metabolomic and transcriptomic investigations, we delineated the biosynthetic pathways responsible for bitter compounds in bamboo shoots, encompassing "phenylpropanoid biosynthesis," "glycolysis/gluconeogenesis," circadian rhythm, and amino acid metabolism pathways. Moreover, we singled out four bitter compounds—3-caffeoylquinic acid, arbutin, phenylalanine, and tryptophan—from the regulatory pathways for targeted metabolic verification. Notably, arbutin exhibited a remarkable 242.52% increase from DoS to DoB, underscoring its pivotal role as a bitter metabolite in unearthed bamboo shoots. Our findings offer crucial insights into the mechanisms underpinning bamboo shoot bitterness, thereby facilitating the cultivation of superior-quality bamboo shoots.