Abstract

The shape and size of grape are critical external quality traits that directly determine their commercial value. Although NF-Y family members are known to regulate fruit shape, their specific roles in grapes remain poorly understood. Here, we identified 31NF-Yfamily genes in grape. Systematic analysis of their phylogeny, gene structures, and conserved motifs highlighted the evolutionary conservation of this family. Phylogenetic comparison of the NF-YA subfamily acrossArabidopsis, rice, tomato, and grape revealed thatVvNF-YA3andVvNF-YA5are orthologs ofSlNF-YA8. Expression profiling showed thatVvNF-YA3expression peaks at anthesis and three days after anthesis. Heterologous overexpression ofVvNF-YA3in K326 tobacco significantly reduced leaf length, leaf shape index, corolla tube length, and pod dimensions. Moreover, its overexpression inNicotiana benthamianaresulted in larger but fewer leaf cells, accompanied by the downregulation of cell cycle genes responsible for cell division. Mechanistically, we identified VvSKIP34 as a VvNF-YA3-interacting protein andVvIQD8as its downstream target gene. Overexpression ofVvIQD8in K326 tobacco yielded narrower leaves and pods, while significantly increasing corolla tube length, pod length, and fruit shape index. Collectively, these findings identify a VvNF-YA3-VvSKIP34-VvIQD8 module that controls cell division and fruit shape in tobacco, providing a functional link betweenVvNF-YA3andVvIQD8and suggesting a potential regulatory mechanism for fruit morphogenesis in grape.