P-288 - Identifying and characterizing the NLR immune receptor network against root-knot nematodes in sweet potato

Plants rely on their immune system to defend against pathogens, including plant-parasitic nematodes. Integral to this system are nucleotide-binding domain and leucine-rich repeat-containing (NLR) proteins, commonly referred to as resistance (R) genes. In Asterids, a large number of NLRs function in a network where “sensor” NLRs directly or indirectly detect pathogen effectors and “helper” NLRs induce downstream immune signalling. While well studied in Solanaceous plants, this system remains largely unexplored in Convolvulaceae, including sweet potato (Ipomoea batatas). The root-knot nematode (RKN) Meloidogyne enterolobii is an emerging threat to sweet potato, but how NLRs mediate resistance to RKNs remains unknown. We have recently delineated the phylogenetic network of NLRs in sweet potato using genomic and transcriptomic data and successfully characterized parts of the network. To identify NLRs important during RKN infection, we performed a dual transcriptomic study of sweet potato roots infected with M. enterolobii at early-stages of the infection. During compatible interaction, we found a concerted downregulation of several helper and sensor NLRs as early as 3 days post infection. On the other hand, a large proportion of the nematode’s secretome and putative effectors were found to be upregulated. Experiments to dissect the underlying regulatory mechanism of this suppression and the corresponding effectors involved are underway, and latest findings will be discussed.