CRISPR/Cas9-mediated editing of PHYTOENE DESATURASE gene in onion (Allium cepa L.)

Frontiers in Plant Science

Plant Science

Viswanathan Satheesh¹  Sivalingam Anandhan²  Pawan Mainkar²  Tushar Kashinath Manape² 

[1] Genome Informatics Facility, Office of Biotechnology, Iowa State University, Ames, IA, United States;ICAR-Directorate of Onion and Garlic Research, Pune, Maharashtra, India;

关键词: PDS;    onion transformation;    CRISPR/Cas9;    genome editing;    chlorophyll;   

DOI  :  10.3389/fpls.2023.1226911

 received in 2023-05-22, accepted in 2023-07-28,  发布年份 2023

来源: Frontiers

【 摘 要 】

IntroductionClustered regularly interspaced short palindromic repeats (CRISPR)/ CRISPR-associated protein 9 (Cas9) is a precise genome editing tool used to introduce genetic modifications in a wide range of crop species. Thus far, there is no report of CRISPR/Cas9-mediated genome editing in onions (Allium cepa L.). MethodsIn the present study, we targeted two exons of the gene coding for Phytoene desaturase (AcPDS) in onion cv. Bhima Super. The sgRNA-carrying constructs were co-cultivated with 8-week-old embryogenic calli using an Agrobacterium-mediated transformation protocol and incubated on the media without hygromycin B selection. Results and discussionOut of the total 617 co-cultivated calli, 21 (3.4%) regenerated shoots exhibited three distinct phenotypes: albino, chimeric, and pale green; in comparison to the wild-type non-transformed regenerated shoots. Total chlorophyll content was drastically reduced in albino shoots and significantly decreased in chimeric shoots. Out of the six Cas9 gene PCR-confirmed regenerated shoots, two exhibited the albino phenotype due to insertions/deletions (InDels) and substitution-based mutations in and around the AcPDS target sites. Deep amplicon sequencing revealed a significantly variable InDel frequency between two sgRNAs, ranging from 1.2% to 63.4%, along with a 53.4% substitution frequency. The mutation of the AcPDS gene generated a visually detectable albino phenotype, thus confirming the successful editing of the AcPDS gene. This is the first time a CRISPR/Cas9-mediated genome editing protocol has been successfully established in onion, with the AcPDS gene serving as an example. This study will provide the necessary momentum for researchers to further basic and applied research on onions.

【 授权许可】

Unknown   
Copyright © 2023 Mainkar, Manape, Satheesh and Anandhan