CRISPR technology is revolutionizing the improvement of tomato and other fruit crops

Abstract

Fruits are major sources of essential nutrients and serve as staple foods in some areas of the world. The increasing human population and changes in climate experienced worldwide make it urgent to the production of fruit crops with high yield and enhanced adaptation to the environment, for which conventional breeding is unlikely to meet the demand. Fortunately, clustered regularly interspaced short palindromic repeat (CRISPR) technology paves the way toward a new horizon for fruit crop improvement and consequently revolutionizes plant breeding. In this review, the mechanism and optimization of the CRISPR system and its application to fruit crops, including resistance to biotic and abiotic stresses, fruit quality improvement, and domestication are highlighted. Controversies and future perspectives are discussed as well.

Keywords: Genetic engineering; Molecular engineering in plants.

Fig. 1. The mechanism of CRISPR-Cas9-mediated genome engineering in plants.

The sgRNA directs the SpCas9 protein to bind genomic DNA through a 20-nucleotide sequence and further guides it to introduce a DSB. This DSB causes random mutations when repaired by the error-prone NHEJ pathway or precise gene modification when repaired by the error-free HDR pathway. CRISPR, clustered regularly interspaced short palindromic repeat; Cas, CRISPR-associated; DSB, double-strand break; HDR, homology-directed repair; NHEJ, non-homologous end-joining; sgRNA, single-guide RNA

Fig. 2

Timeline of the first application of the clustered regularly interspaced short palindromic repeat-CRISPR-associated (CRISPR-Cas9) system in fruit crops