Integrative transcriptomic and metabolomic profiling reveals candidate SWEET and SUT transporters associated with nectar sugar accumulation in Tilia amurensis

Le résumé fourni par la source

Floral nectar sugar composition is a key trait underlying plant–pollinator interactions and honey production, yet the molecular basis of natural variation in nectar sugar accumulation remains poorly understood in woody nectar-producing species. Tilia amurensis is an important nectar-producing tree species in northeastern China and provides a valuable system for investigating provenance-dependent variation in nectar sugar accumulation. Here, nectar sugar composition was characterized across four T. amurensis provenances, followed by integrated transcriptomic and metabolomic analyses of contrasting high- and low-sugar provenances. High-performance liquid chromatography identified fructose, glucose, sucrose, and maltose in nectar, with fructose and glucose predominating. Nectar sugar composition varied significantly among provenances, with WY and LSH generally showing higher levels of major sugars, whereas RH consistently exhibited the lowest levels of all four measured sugars. Transcriptomic comparison between WY and RH identified 14,513 differentially expressed genes, including 7,577 upregulated and 6,936 downregulated genes. Integrated analyses highlighted carbohydrate metabolism and sugar transport-related pathways associated with provenance-dependent differences in nectar sugar accumulation. SWEET9 and SUT4 exhibited differential expression patterns consistent with variation in nectar sugar accumulation. These findings identify candidate metabolic pathways and sugar transporters associated with nectar sugar variation and provide a multi-omics resource for generating hypotheses regarding the molecular basis of nectar sugar accumulation in this woody nectar-producing species.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.