Targeted creation of new mutants with compact plant architecture using CRISPR/Cas9 genome editing by an optimized genetic transformation procedure in cucurbit plants

Fruits and vegetables in the Cucurbitaceae family, such as cucumber, melon, watermelon, and squash, contribute greatly to the human diet. The widespread use of genome editing technologies has greatly accelerated gene functional characterization and crop improvement. However, most economically important cucurbit plants, including melon and squash, remain recalcitrant to standard Agrobacterium tumefaciens-mediated transformation, limiting the effective use of genome editing technology. In this study, we used an “optimal infiltration intensity” strategy to establish an efficient genetic transformation system for melon and squash. We harnessed the power of this method to target homologs of the ERECTA family of receptor kinase genes and created alleles that resulted in a compact plant architecture with shorter internodes in melon, squash, and cucumber. The optimized transformation method presented here enables stable CRISPR/Cas9-mediated mutagenesis and provides a solid foundation for functional gene manipulation in cucurbit crops.