Papaya is an economically significant crop in Hawaiʻi and other tropical and subtropical locales. However, various diseases, drought, and heat stress threaten crop productivity.
To improve resistance to these threats, an efficient gene-editing system was developed by graduate student, Marc Elias, in the laboratory of David Christopher in the Dept. of Molecular Biosciences and Bioengineering, as well as in collaboration with Miaoying Tian, formerly of the Dept. of Plant and Environmental Protection Sciences.
The innovative aspects of this method target single-celled protoplasts and use a DNA-free CRISPR-Cas9 gene-editing system. Marc found that three different genes were successfully demonstrated to be edited, one of which is the disease-resistant gene, MLO6. This gene holds promise for developing resistance to the papaya wilt disease caused by the pathogen Phytophthora palmivora.
The DNA-free CRISPR-Cas9 gene-editing approach is less intrusive than traditional genetic engineering. The transgene-free method eliminates the introduction of transgenic material into the papaya genome, reducing off- target mutations and lessening regulatory concerns. It will streamline navigating regulatory processes for farmers and commercialization of improved papaya varieties.
Marc’s study, Development of a Mesophyll Protoplast-Based System for Gene Editing of Papaya, was recently published in the journal In Vitro Cellular and Developmental Biology.