The regulatory network of sex differentiation in the bisexual kiwifruit ‘Duie A10’ unveiled by integrated transcriptome and metabolome analysis

• Uses rare bisexual kiwifruit ‘Duie A10’ as material, offering an ideal model for kiwifruit sex differentiation and overcoming traditional dioecious materials’ genetic background inconsistency. • Integrates cytomorphological observation, physiological determination, transcriptome-metabolome analysis to reveal ‘Duie A10’ sex differentiation’s multi-dimensional regulatory networks. • Identifies phenylpropanoid biosynthesis and plant hormone signal transduction as core pathways; WGCNA screens Lightcyan1 gene/Brown metabolite modules linked to sex phenotypes. • Clarifies male flower pistil abortion starts at bisexual stage (style atrophy, no ovule primordia); polyamines and endogenous hormones synergistically regulate sex differentiation via spatiotemporal differences. To elucidate the mechanism of sex differentiation in bisexual kiwi flowers, this study used bisexual flowers (Lh) and male flowers (Xh) of the kiwifruit cultivar 'Duie A10′ as materials, integrating cytomorphological observations, physiological determinations, and multi-omics analysis. Cytomorphological results showed that the stamens and pistils of bisexual flowers developed completely, while pistil abortion in male flowers initiated at the bisexual stage (manifested as style atrophy and lack of ovule primordia). There was no significant difference in pollen viability between the two flower types. Physiological analysis revealed that polyamines such as tryptamine, β-phenethylamine, indole-3-propionic acid (IPA), and trans-zeatin riboside (TZR), as well as endogenous hormones, exhibited temporal and spatial specific differences, which may synergistically regulate sex differentiation. Through combined transcriptomic and metabolomic analysis, a total of 2643 differentially expressed metabolites (DEMs) and a large number of differentially expressed genes (DEGs) were identified. KEGG enrichment analysis indicated that phenylpropanoid biosynthesis and plant hormone signal transduction were the core pathways. Weighted Gene Co-expression Network Analysis (WGCNA) screened out the Lightcyan1 gene module and Brown metabolite module that were highly associated with sex phenotypes. This study reveals the morphological, physiological, and molecular regulatory networks underlying sex differentiation in 'Duie A10′ , providing theoretical support and genetic resources for the breeding of self-pollinating kiwifruit cultivars.