The Arabidopsis lectin receptor kinase LecRK‐I.9 enhances resistance to Phytophthora infestans in Solanaceous plants

Summary Late blight caused by the plant pathogenic oomycete Phytophthora infestans is known as one of the most destructive potato diseases. Plant breeders tend to employ NB ‐ LRR ‐based resistance for introducing genetically controlled late blight resistance in their breeding lines. However, P. infestans is able to rapidly escape this type of resistance, and hence, NB ‐ LRR ‐based resistance in potato cultivars is often not durable. Previously, we identified a novel type of Phytophthora resistance in Arabidopsis. This resistance is mediated by the cell surface receptor Lec RK ‐I.9, which belongs to the family of L‐type lectin receptor kinases. In this study, we report that expression of the Arabidopsis Lec RK ‐I.9 gene in potato and Nicotiana benthamiana results in significantly enhanced late blight resistance. Transcriptional profiling showed strong reduction in salicylic acid ( SA )‐mediated defence gene expression in Lec RK ‐I.9 transgenic potato lines (TPLs). In contrast, transcripts of two protease inhibitor genes accumulated to extreme high levels, suggesting that Lec RK ‐I.9‐mediated late blight resistance is relying on a defence response that includes activation of protease inhibitors. These results demonstrate that the functionality of Lec RK ‐I.9 in Phytophthora resistance is maintained after interfamily transfer to potato and N. benthamiana and suggest that this novel type of Lec RK ‐based resistance can be exploited in breeding strategies to improve durable late blight resistance in Solanaceous crops.