Telomere-to-telomere genome assembly of eggplant (Solanum melongena L.) promotes gene fine localization of the green stripe (GS) in pericarp.

Fruit appearance of eggplant is a key commercial trait, and the precise selection of new varieties with diverse aesthetics aligns with current breeding objectives. However, functional genomics research in eggplant remains underdeveloped. Here, we assembled the first telomere-to-telomere (T2T) eggplant genome, as well as chloroplast and mitochondrial genomes for the inbred line 'NO211'. The 1.06-Gb SmT2T genome is anchored to 12 chromosomes, nine of which are gap-free, totaling three gaps. This assembly harbors 36,505 genes and 64.08 % repetitive sequences, identifying 12 centromeres and 22 telomeres. Utilizing the SmT2T genome for bulked segregant analysis (BSA) and forward genetic approach with green-striped 'NO211' and pure green 'P13' as parents, the green stripe (GS) locus was finely mapped to a 9-Kb region on Chr4, containing a single gene, eggplant.04G07850 (GLK protein). Sequence analysis and qRT-PCR revealed that a single-base deletion in the exon of SmGLK in 'P13' led to premature stop codon, and SmGLK expression was significantly higher in the pericarp of 'NO211' compared to 'P13'. A marker was developed and validated in 36 germplasms, demonstrating co-segregation with green-striped rind trait. This study provides an ideal reference genome for eggplant functional genomics studies, facilitating mechanistic research on peel stripe formation and molecular-assisted selection for fruit appearance.