Potato plants transformed with the Arabidopsis EF-Tu receptor (EFR) show restricted pathogen colonization and enhanced bacterial wilt resistance under conditions resembling natural field infections

Abstract

Potato is considered a staple food in the world and its production is limited by the presence of bacterial wilt (bw) disease caused by Ralstonia solanacearum. Host resistance is the most sustainable and cost-effective strategy to manage bw, although resistant commercial potato cultivars are not yet available. Our group incorporated the efr receptor of Arabidopsis thaliana (atefr), which recognizes the elongation factor Tu, preserved in bacteria, triggering an immune response. atefr was tested in two genetic backgrounds: a susceptible commercial cultivar (inia Iporá) and a breeding clone with partial resistance introgressed from Solanum commersonii. In this work, the effect of the atefr receptor on bw resistance was evaluated for the first time, using conditions resembling natural field infection. In addition, the colonization patterns of wild-type and transgenic lines were compared by using luminescent and fluorescent R. solanacearum reporter strains. Both approaches showed a delay and a decrease in the severity of wilting symptoms in the atefr-transformed genotypes. Differential colonization patterns were observed, revealing a higher bacterial development in the non-transformed plants. This atefr effect seems more pronounced in the interspecific breeding line, possibly leading to a more effective activation of the plant immune system.