CRISPR/Cas9 genome editing of potato StDMR6-1 results in plants less affected by different stress conditions

Abstract

Potato is the third most important food crop, but cultivation is challenged by numerous diseases and adverse abiotic conditions. To combat diseases, frequent fungicide application is common. Knocking out susceptibility genes by genome editing could be a durable option to increase resistance. DMR6 has been described as a susceptibility gene in several crops, based on data that indicates increased resistance upon interruption of the gene function. In potato, Stdmr6-1 mutants have been described to have increased resistance against the late blight pathogen Phytophthora infestans in controlled conditions. Here, we present field evaluations of CRISPR/Cas9 mutants, in a location with a complex population of P. infestans, during four consecutive years that indicate increased resistance to late blight without any trade-off in terms of yield penalty or tuber quality. Furthermore, studies of potato tubers from the field trials indicated increased resistance to common scab, and the mutant lines exhibit increased resistance to early blight pathogen Alternaria solani in controlled conditions. Early blight and common scab are problematic targets in potato resistance breeding, as resistance genes are very scarce. The described broad-spectrum resistance of Stdmr6-1 mutants may further extend to some abiotic stress conditions. In controlled experiments of either drought simulation or salinity, Stdmr6-1 mutant plants are less affected than the background cultivar. Together, these results demonstrate the prospect of the Stdmr6-1 mutants as a useful tool in future sustainable potato cultivation without any apparent trade-offs.

Acknowledgements

This work was financially supported by Novo Nordisk Foundation (NNF19OC0057208), SLF (R-19-25-282), Formas (2020-0121; 2019-00512; 2023-01294), as well as Lyckeby Starch and KMC. We thank Mirte de Boer for assistance in maintaining potato plant material and contributing to sample preparation for qPCR.

Author contributions

M.K, N.P.K., S.A., and E.A. jointly conceptualized the study. The investigation was carried out by M.K., N.P.K., M.A.Z., M.L., and S.R. Funding acquisition was managed by E.A., N.P.K. and M.L. The original draft was written by M.K., and E.A. contributed to writing and editing. All authors reviewed the manuscript before submission.

Data availability

Biological material are available upon request to Erik Andreasson ([e-mail]). The numeric data used for presentation in this article are available in supplementary data S2.

Conflict of interest statement

EA, SR, MAZ and NPK has a patent application relating to presented data SE 2430222-6.

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