Soybean cyst nematode (SCN) and Phytophothora sojae are two most destructive soybean pathogens responsible for more than $1 billion and $200 million, respectively, in annual soybean yield losses in the U.S. Deployment of genes conferring resistances to these pathogens into soybean cultivars is an effective solution to reduce yield losses. However, identification, integration, and pyramiding of such genes and natural variations into an elite cultivar take years or decades to achieve, representing a challenge in genetic management of these diseases. Now, the CRISPR-Cas9 genome-editing technology has revolutionized the way in which agricultural research is conducted. In particular, the technology enables rapid, precise, and targeted changes of the soybean genome/DNA for desirable traits. Such changes are essentially similar or identical to those created by the Mother Nature and thus exempt from regulation. The goal of this project is to create novel genetic variation at the Rhg1 locus for enhanced resistance to SCN and at the rps2-b locus for broad-spectrum resistance to P. sojae using the CRISPR-Cas9 genome-editing technology. This innovative approach, if successful, can be directly applied to convert "susceptibility" into "resistance" to these diseases in any elite cultivars that would significantly reduce input cost-to-benefit ratios for Indiana soybean producers. In addition to new sources of resistances to be created, this project will help us maintain and optimize soybean transformation and gene-editing protocols to facilitate Purdue's basic and applied soybean research, and to help undergraduate students gain cutting-edge hands-on experience as an integral part of our commitment to undergraduate education.

1. Test the efficiency of genome editing at the Rhg1 locus for increased copy numbers of the functional Rhg1 gene block through hairy root transformation and genome editing.
2. Develop stable soybean lines with increased copy numbers of the functional Rhg1 gene block for enhanced SCN resistance through whole plant transformation and genome-editing.
3. Test the efficiency of genome editing at the rps-2 region for formation of a chimeric Rps2-b-like gene through hairy root transformation and genome editing.
4. Develop stable soybean lines with chimeric Rps2-b-like gene for Phytophthora resistance through whole plant transformation and genome-editing.
5. Optimize the soybean transformation and genome-editing protocols for both basic and applied research.

1. Identify highly efficient gRNAs towards targeted and desirable genome editing at the Rhg1 gene block.
2. 2-3 soybean progeny lines with increased copy numbers of the Rhg1 gene lock; Frequencies of deletion and duplication at the targeted genome editing sites.
3. Information about the efficiency of pairs of gRNAs for targeted deletion.
4. 2-3 soybean progeny lines in which a Rps2-like chimeric structure is induced by CRISPR-Cas9; Frequencies of deletion and duplication at the targeted genome editing sites.
5. Optimized protocols for soybean transformation and genome editing; Identification of an elite soybean cultivar that can be used for transformation and genome-editing.

We will communicate our research results through Purdue News and scientific meetings such as Soybean Breeders' Workshop, Biennial Conference on Molecular and Cellular Biology of Soybean, and/or the Plant & Animal Genome Conference. We will also apply for patents and publish the results in scientific journals, exhibit soybean lines with increased SCN and Phytophthora resistance to soybean breeders and Indiana soybean producers through Field Days and Soybean Showcase that are routinely held at Purdue Agronomy Farm. The success of our project will reflect the success of our Indiana soybean producers' investment and strengthen the reputation of Indiana soy.

Update:

View uploaded report

Our capability to change soybean genome DNA by using CRISPR-Cas9 has encouraged us to explore this first-of-its-kind approach to sustainable management of the two major soybean diseases. The impact of this project, upon its completion, will be significant and realized by both scientific community as well as the soybean producers and industry. As a longer-term impact, the strategy and approach developed in this project can be applied to create new disease resistance in elite soybean cultivars and even other crops such as corn.