Mutagenesis of seed storage protein genes in Soybean using CRISPR/Cas9

Citation

Li, C., Nguyen, V., Liu, J., Fu, W., Chen, C., Yu, K., Cui, Y. (2019). Mutagenesis of seed storage protein genes in Soybean using CRISPR/Cas9. BMC Research Notes, [online] 12(1), http://dx.doi.org/10.1186/s13104-019-4207-2

Plain language summary

Conventionally, breeders have to repeatedly introgress the mutations into elite soybean cultivars by conducting genetic crosses and rounds of selection over several generations and years. This is a long and labour-intensive process, which has been a major limiting factor for the timely delivery of quality soybean varieties, in an effort to cope with a continuously changing agriculture environment. Even though new plant breeding techniques have been constantly sought after by the plant genetics and genomics research community, it seems that the CRISPR-Cas9 system (the Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR)/CRISPR-associated 9 (Cas9)) is revolutionizing our breeding practices.

The CRISPR/Cas9 system has emerged as a robust technology for efficient genome editing, and has been successfully applied in many major crops, including soybean. Soybean seeds are an important source of vegetable proteins for both food and industry world-wide. Two major families of storage proteins, conglycinins (7S) and glycinins (11S), account for about 70% of total soy seed protein. Both quantity and quality of storage proteins, in soybean seeds, are major biochemical components influencing the quality of tofu and other soy food products. In this study, we set out to test the efficiency of the CRISPR/Cas9 system in editing soybean storage protein genes using Agrobacterium rhizogenes-mediated hairy root transformation system which only takes about 3 weeks. Therefore, assessing the efficiency of generating mutations at target sites in hairy roots could solve the labor-intensive problem of the traditional breeding techniques.

Abstract

Objective: Soybean seeds are an important source of vegetable proteins for both food and industry worldwide. Conglycinins (7S) and glycinins (11S), which are two major families of storage proteins encoded by a small family of genes, account for about 70% of total soy seed protein. Mutant alleles of these genes are often necessary in certain breeding programs, as the relative abundance of these protein subunits affect amino acid composition and soy food properties. In this study, we set out to test the efficiency of the CRISPR/Cas9 system in editing soybean storage protein genes using Agrobacterium rhizogenes-mediated hairy root transformation system. Results: We designed and tested sgRNAs to target nine different major storage protein genes and detected DNA mutations in three storage protein genes in soybean hairy roots, at a ratio ranging from 3.8 to 43.7%. Our work provides a useful resource for future soybean breeders to engineer/develop varieties with mutations in seed storage proteins.