Development of Improved Fruit, Vegetable, and Ornamental Crops Using the CRISPR/Cas9 Genome Editing Technique.

Jude W. Grosser,Manjul Dutt,Tatiana S. Moraes,Lamiaa M. Mahmoud,Zhonglin Mou,Lígia Erpen-Dalla Corte

doi:10.3390/plants8120601

Abstract

Horticultural crops, including fruit, vegetable, and ornamental plants are an important component of the agriculture production systems and play an important role in sustaining human life. With a steady growth in the world’s population and the consequent need for more food, sustainable and increased fruit and vegetable crop production is a major challenge to guarantee future food security. Although conventional breeding techniques have significantly contributed to the development of important varieties, new approaches are required to further improve horticultural crop production. Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) has emerged as a valuable genome-editing tool able to change DNA sequences at precisely chosen loci. The CRISPR/Cas9 system was developed based on the bacterial adaptive immune system and comprises of an endonuclease guided by one or more single-guide RNAs to generate double-strand breaks. These breaks can then be repaired by the natural cellular repair mechanisms, during which genetic mutations are introduced. In a short time, the CRISPR/Cas9 system has become a popular genome-editing technique, with numerous examples of gene mutation and transcriptional regulation control in both model and crop plants. In this review, various aspects of the CRISPR/Cas9 system are explored, including a general presentation of the function of the CRISPR/Cas9 system in bacteria and its practical application as a biotechnological tool for editing plant genomes, particularly in horticultural crops.

Highlights

Introduction to Genome EditingHistorically, genetic modifications at the DNA level have resulted in the development of improved plant varieties
It was observed that by modifying the PthA4 effector cis-elements in the promoter of CsLOB1 by using the Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system there was a reduced Xanthomonas citri subspecies citri (Xcc) infection on the mutant plants [76]. These results revealed though that only plants with mutations in the promoters of both alleles of CsLOB1 were resistant to citrus canker, suggesting that activation of a single allele of the CsLOB1 gene via the PthA4 binding element is sufficient for disease initiation
Edited plants were early ripening in nature and this study provided new insights into the role of FUL1 and FUL2 during fruit ripening

Summary

Introduction to Genome Editing

Genetic modifications at the DNA level have resulted in the development of improved plant varieties. Cas is guided by sgRNA and requires the PAM sequence to recognize the target site and differentiate between self and Plants. Unlike CRISPR/Cas, theFrancisella, CRISPR/Cpf system requires a single crRNA that does not need to couple with a tracrRNA, has been used as a nuclease in plant genome editing [29,30,31]. Their optimal design is critical for successful editing It is alsoto minimize off-target possibilities, i.e.,possibilities, when sgRNA matches sites that are similar to the important to minimize off-target i.e., when additional sgRNA matches additional sites thattarget are sequences, unwanted mutations could occur [37,38].

Select

Genome Editing in Fruit Crops

Genome Editing in Vegetable Crops

Genome Editing in Ornamental Crops

Findings

Conclusions