The Ralstonia pseudosolanacearum effector RipE1 is recognized at the plasma membrane by NbPtr1, the Nicotiana benthamiana homologue of Pseudomonas tomato race 1

• Published in: Molecular plant pathology 2023-10, Vol.24 (10), p.1312-1318
• Main Authors: Kim, Boyoung, Kim, Injae, Yu, Wenjia, Li, Meng, Kim, Haseong, Ahn, Ye Jin, Sohn, Kee Hoon, Macho, Alberto P., Segonzac, Cécile
• Format: Article
• Language: English
• Subjects: Apoptosis; Bacteria; Disease resistance; Gene silencing; Homology; Hypersensitive response; Immune response; Immune system; Leucine; Membranes; Nicotiana benthamiana; Nucleotides; nucleotide‐binding leucine‐rich repeat receptor; Plant bacterial diseases; plant immune system; Plant physiology; Proteins; Pseudomonas; Ralstonia pseudosolanacearum; Ralstonia solanacearum; Receptors; Recognition; Short Communication; Solanaceae; Solanum lycopersicoides; subcellular localization; Tomatoes; type III secreted effectors; Variance analysis; virus‐induced gene silencing; Wilt
• ISSN: 1464-6722; 1364-3703
• DOI: 10.1111/mpp.13363

The bacterial wilt disease caused by soilborne bacteria of the Ralstonia solanacearum species complex (RSSC) threatens important crops worldwide. Only a few immune receptors conferring resistance to this devastating disease are known so far. Individual RSSC strains deliver around 70 different type III secretion system effectors into host cells to manipulate the plant physiology. RipE1 is an effector conserved across the RSSC and triggers immune responses in the model solanaceous plant Nicotiana benthamiana. Here, we used multiplexed virus‐induced gene silencing of the nucleotide‐binding and leucine‐rich repeat receptor family to identify the genetic basis of RipE1 recognition. Specific silencing of the N. benthamiana homologue of Solanum lycopersicoides Ptr1 (confers resistance to Pseudomonas syringae pv. tomato race 1) gene (NbPtr1) completely abolished RipE1‐induced hypersensitive response and immunity to Ralstonia pseudosolanacearum. The expression of the native NbPtr1 coding sequence was sufficient to restore RipE1 recognition in Nb‐ptr1 knockout plants. Interestingly, RipE1 association with the host cell plasma membrane was necessary for NbPtr1‐dependent recognition. Furthermore, NbPtr1‐dependent recognition of RipE1 natural variants is polymorphic, providing additional evidence for the indirect mode of activation of NbPtr1. Altogether, this work supports NbPtr1 relevance for resistance to bacterial wilt disease in Solanaceae. In Nicotiana benthamiana, the homologue of Pseudomonas tomato race 1 (NbPtr1) recognizes the conserved plasma membrane‐localized Ralstonia pseudosolanacearum effector RipE1 and triggers immunity.