Genetic modulation of RAP alters fruit coloration in both wild and cultivated strawberry

摘要

Fruit colour affects consumer preference and is an important trait for breeding in strawberry. Previously, we isolated the ( ) gene encoding a glutathione S‐transferase (GST) that binds anthocyanins to facilitate their transport from cytosol to vacuole in the diploid strawberry . The parent of was the variety ‘Yellow Wonder’ that develops white fruit due to a natural mutation in the gene. Here, we investigated the application potential of in modulating fruit colours by overexpression of in and knockout of in the cultivated strawberry . Unexpectedly, the overexpression in Yellow Wonder background caused formation of red fruit. In addition, the red coloration occurs precociously at floral stage 10 and continues in the receptacle during early fruit development. Transcriptome analysis revealed that the anthocyanin biosynthesis genes were not up‐regulated in flowers at anthesis and largely inhibited at the turning stage in fruit, suggesting a coloration mechanism independent of . Moreover, we used CRISPR/Cas9 to knockout in cultivated strawberry which is octoploid. Six copies of were simultaneously knocked out in the T0 generation leading to the green stem and white‐fruited phenotype. Several T1 progeny have segregated away the CRISPR/Cas9 transgene but maintain the green stem trait. Our results indicate that enhancing the anthocyanin transport could redirect the metabolic flux from proanthocyanidin to anthocyanin production at early developmental stages of fruit and that is one promising candidate gene in fruit colour breeding of strawberry.