PubMed · 2026-05-29
Scientists assembled a complete, high-quality genome of a waterlogging-tolerant kiwifruit rootstock, revealing how its six-copy (hexaploid) genome is structured and identifying a specific gene that, when boosted, helps kiwifruit survive flooded conditions.
The hexaploid genome contains 174 chromosomes across 6 haplotypes, with over 82% of chromosomes telomere-capped and three haplotypes achieving 100% telomeric representation — indicating exceptional assembly completeness.
Approximately 212,055 protein-coding genes were predicted (~35,000 per haplotype), with the subgenome structure traced to two ancestral donors: Actinidia polygama (contributing 2 sub-genomes) and Actinidia macrosperma (contributing 4 sub-genomes).
Overexpression of the B1 haplotype copy of an ethylene-response factor (ERF) gene in transgenic kiwifruit lines conferred enhanced waterlogging resistance, demonstrating subgenome-specific functional divergence.
