HT-B and S-RNase CRISPR-Cas9 double knockouts show enhanced self-fertility in diploid Solanum tuberosum

Tuesday, July 27, 2021
11:00 AM - 11:15 AM


The Gametic Self-Incompatibility (GSI) System in diploid commercial potato (Solanum tuberosum) poses a substantial barrier in potato breeding by hindering the generation of inbred lines. A possible solution is to develop self-compatible diploid potatoes which allow for generation of elite inbred lines with fixed favorable alleles and heterotic potential. The S-RNase and HT genes have been established as contributing factors toward self-incompatibility in the Solanum family and self-compatible S. tuberosum lines have been generated by knocking out S-RNase with CRISPR-Cas9 gene editing. This study utilizes CRISPR-Cas9 to knockout a HT gene (HT-B) either individually or in concert with S-RNase in the diploid S. tuberosum line DRH-195. Using seed count from self-pollinated fruit as the essential defining characteristic of self-compatibility, HT-B only knockouts did not produce self-compatible lines. In contrast, double knockout lines of HT-B and S-RNase displayed levels of fertility that were up to three times higher than targeting S-RNase alone, indicating a possible synergistic effect between HT-B and S-RNase toward self-compatibility in diploid potato. Contradictory to the traditional GSI model, self-incompatible lines displayed pollen tube growth reaching the ovary indicating Late-Acting Self-Incompatibility in DRH-195. Lines generated from this study will serve as a self-compatible resource for diploid potato breeding.

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