A Truncated TIR-NBS Protein TN10 Pairs with Two Clustered TIR-NBS-LRR Immune Receptors and Contributes to Plant Immunity in .

The encoding genes of plant intracellular nucleotide-binding site (NBS) and leucine-rich repeat (LRR) domain receptors (NLRs) often exist in the form of a gene cluster. Several recent studies demonstrated that the truncated Toll/interleukin-1 receptor-NBS (TIR-NBS) proteins play important roles in immunity. In this study, we identified a large gene cluster on ecotype Col-0 chromosome 1, which included nine genes, to . Interestingly, this cluster also contained two typical genes: and (hereinafter referred to as and respectively), which formed head-to-head genomic arrangement with to . However, the functions of these and genes in this cluster are still unknown. Here, we showed that the TIR domains of both TNL40 and TNL60 associated with TN10 specifically. Furthermore, both TNL40TIR and TNL60TIR induced cell death in leaves. Subcellular localization showed that TNL40 mainly localized in the cytoplasm, whereas TNL60 and TN10 localized in both the cytoplasm and nucleus. Additionally, the expression of , , and were co-regulated after inoculated with bacterial pathogens. Taken together, our study indicates that the truncated TIR-NBS protein TN10 associates with two clustered TNL immune receptors, and may work together in plant disease resistance.