AUTHOR=Lucioli Alessandra , Tavazza Raffaela , Baima Simona , Fatyol Karoly , Burgyan Jozsef , Tavazza Mario 

TITLE=CRISPR-Cas9 Targeting of the eIF4E1 Gene Extends the Potato Virus Y Resistance Spectrum of the Solanum tuberosum L. cv. Desirée

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.873930

DOI=10.3389/fmicb.2022.873930

ISSN=1664-302X

ABSTRACT=<p>Translation initiation factors and, in particular, the eIF4E family are the primary source of recessive resistance to potyviruses in many plant species. However, no eIF4E-mediated resistance to this virus genus has been identified in potato (<italic>Solanum tuberosum</italic> L.) germplasm. As in tomato, the potato eIF4E gene family consists of <italic>eIF4E1</italic>, its paralog <italic>eIF4E2, eIF(iso)4E</italic>, and <italic>nCBP</italic>. In tomato, <italic>eIF4E1</italic> knockout (KO) confers resistance to a subset of potyviruses, while the <italic>eIF4E1/2</italic> double KO, although conferring a broader spectrum of resistance, leads to plant developmental defects. Here, the tetraploid potato cv. Desirée owning the dominant <italic>Ny</italic> gene conferring resistance to potato virus Y (PVY) strain O but not NTN was used to evaluate the possibility to expand its PVY resistance spectrum by CRISPR-Cas9-mediated KO of the <italic>eIF4E1</italic> susceptibility gene. After a double process of plant protoplast transfection-regeneration, <italic>eIF4E1</italic> KO potatoes were obtained. The knockout was specific for the <italic>eIF4E1</italic>, and no mutations were identified in its <italic>eIF4E2</italic> paralog. Expression analysis of the eIF4E family shows that the disruption of the <italic>eIF4E1</italic> does not alter the RNA steady-state level of the other family members. The <italic>eIF4E1</italic> KO lines challenged with a PVY<sup>NTN</sup> isolate showed a reduced viral accumulation and amelioration of virus-induced symptoms suggesting that the <italic>eIF4E1</italic> gene was required but not essential for its multiplication. Our data show that <italic>eIF4E1</italic> editing can be usefully exploited to broaden the PVY resistance spectrum of elite potato cultivars, such as Desirée, by pyramiding eIF4E-mediated recessive resistance.</p>