Clean gene technology for precision breeding and genetic improvement of vegetable crops

Abstract

Worldwide demand for vegetable production is accelerating due to population growth and increasing health awareness. Although traditional plant breeding is successful for vegetable production, it is time-consuming and constrained by sexual compatibility. The emergence of transgenic technology has provided a breakthrough, but it has encountered significant public and regulatory challenges due to selectable marker genes (SMGs) and foreign DNA. Therefore, the term clean gene technology, or marker-free transformation, emerged to describe a set of advanced molecular methods aimed at producing genetically modified (GM) plants that lack SMGs and foreign DNA. A radical option is provided by clean gene technology, which includes such methods as CRISPR-Cas and oligonucleotide-directed mutagenesis (ODM). These technologies enable targeted, accurate changes to the plant genome without adding foreign DNA to the final product. This paper summarizes the concepts, major approaches (site-specific recombination, transposon systems, and genome editing). It reviews the fundamentals, use, and future opportunities of clean gene technology for improving essential characteristics of vegetable crops, such as yield, quality, resistance to diseases, and tolerance to abiotic stress, as well as the regulatory and social environment.