CRISPR/Cas9‐mediated genome editing of MaACO1 (aminocyclopropane‐1‐carboxylate oxidase 1) promotes the shelf life of banana fruit

The results showed that among the MaACO gene family, Ma07_t19730.1 and Ma03_t02700.1 showed high transcript abundance under natural conditions in both pulp and peel tissues (day 0), and the highest transcript abundance of Ma07_t19730.1 and Ma03_t02700.1 occurred in pulp and peel tissues, respectively, in all of the examined MaACOs (Figure 1a, day 0). [...]the transcripts of these ACO genes were strongly induced by ethephon and were inhibited by 1‐MCP to a greater extent in Ma07_t19730.1 in both the pulp and peel (Figure 1a), which suggests that Ma07_t19730.1 might play a more important role than Ma03_t02700.1 in banana fruit ripening. Importantly, when the banana fruit of the wild‐type and MaACO1‐disrupted plants was treated with ethephon, they exhibited a similar response to ethephon and ripened normally (Figure 1g). [...]the ripening process of the MaACO1‐disrupted fruit was delayed for about 1–2 days compared to that of wild‐type fruit, implying improved shelf life for the MaACO1‐disrupted fruit after ethephon treatment. [...]the TSS, total sugar and total acid contents of these two lines were also comparable for completely ripe fruits, and the MaACO1‐disrupted fruit has more vitamin C than that of wild type (Figure 1i), suggesting that MaACO1 strongly affects banana shelf life and is an ideal target gene to edit for improved shelf life. The mutant fruits exhibited reduced ethylene synthesis and extended shelf life under natural ripening conditions. [...]MaACO1‐disrupted fruit was also sensitive to ethephon and ripened normally after ethephon treatment.