Elicitor-Mediated Oligomerization of the Tobacco N Disease Resistance Protein[W],[OA]
Pere Mestre1 and David C. Baulcombe2
Sainsbury Laboratory, John Innes Centre, Norwich NR4 7UH, United Kingdom
2 To whom correspondence should be addressed. E-mail [email protected]
; fax 44-1603-450011.
Plant nucleotide binding site–leucine-rich repeat (NBS-LRR) proteins are similar to the nucleotide binding oligomerization domain (NOD) protein family in their domain structure. It has been suggested that most NOD proteins rely on ligand-mediated oligomerization for function, and we have tested this possibility with the N protein of tobacco (Nicotiana tabacum). The N gene for resistance to Tobacco mosaic virus (TMV) is a member of the Toll-interleukin receptor (TIR)-NBS-LRR class of plant disease resistance (R) genes that recognizes the helicase domain from the TMV replicase. Using transient expression followed by immunoprecipitation, we show that the N protein oligomerizes in the presence of the elicitor. The oligomerization was not affected by silencing Nicotiana benthamiana ENHANCED DISEASE SUSCEPTIBILITY1 and N REQUIREMENT GENE1 cofactors of N-mediated resistance, but it was abolished by a mutation in the P-loop motif. However, loss-of-function mutations in the RNBS-A motif and in the TIR domain retain the ability to oligomerize. From these results, we conclude that oligomerization is an early event in the N-mediated resistance to TMV.
The Plant Cell 18:491-501 (2006). Open Access Article.