Azuma, A. | Search bioRxiv

bioRxiv2026

Accumulation of two distinct alleles causes astringency loss in cultivated polyploid persimmon

Persimmon fruit accumulates high levels of proanthocyanidins (PAs), causing extreme astringency. In pollination-constant and non-astringent (PCNA) cultivars, PA accumulation ceases early in fruit development. Although the PCNA trait is recessively controlled by the ASTRINGENCY (AST) locus, its causal gene has remained unknown. Using haplotype-resolved forward genetics in a hexaploid genetic background, we identified the previously uncharacterized TANNIN (TAN) as the causal gene. Long-read sequencing revealed that PCNA originated through the accumulation of independently derived ast alleles that cause transcriptional deficiency of TAN. These findings resolve the complex genetic basis of natural astringency loss in persimmon and provide a framework for molecular breeding. Further investigation of TAN function would uncover mechanisms underlying massive accumulation of PAs in persimmon fruit and insight into specialized metabolite sequestration.

plant biology↗

bioRxiv2019

De novo whole-genome assembly in interspecific hybrid table grape, ‘Shine Muscat’

This study presents the first genome sequence of an interspecific grape hybrid, Shine Muscat (Vitis labruscana x V. vinifera), an elite table grape cultivar bred in Japan. The complexity of the genome structure, arising from the interspecific hybridization, necessitated the use of a sophisticated genome assembly pipeline with short-read genome sequence data. The resultant genome assemblies consisted of two types of sequences: a haplotype-phased sequence of the highly heterozygous genomes and an unphased sequence representing a \"haploid\" genome. The unphased sequences spanned 490.1 Mb in length, 99.4% of the estimated genome size, with 8,696 scaffold sequences with an N50 length of 13.2 Mb. The phased sequences had 15,650 scaffolds spanning 1.0 Gb with N50 of 4.2 Mb. The two sequences comprised 94.7% and 96.3% of the core eukaryotic genes, indicating that the entire genome of Shine Muscat was represented. Examination of genome structures revealed possible genome rearrangements between the genomes of Shine Muscat and a V. vinifera line. Furthermore, full-length transcriptome sequencing analysis revealed 13,947 gene loci on the Shine Muscat genome, from which 26,199 transcript isoforms were transcribed. These genome resources provide new insights that could help cultivation and breeding strategies produce more high-quality table grapes such as Shine Muscat.

genomics↗