Figure 1.

A 21-Amino Acid Peptide Region in NSm Is Sufficient to Induce Sw-5b-Mediated Cell Death.

(A) Analyses of NSm deletion mutants for the induction of cell death in the presence of Sw-5b. The truncated mutants of NSm with their remaining amino acids are shown below the full-length 303-amino acid NSm. The severity of the cell death induced by each construct is shown on the right side. (−) to (+++++) indicate the severity of cell death on a scale of 0 to 5, as shown in Supplemental Figure 2.

(B) Fine mapping of the region in NSm required for the induction of cell death. The NSm truncated mutants shown were fused individually to the N terminus of YFP, and transiently coexpressed with Sw-5b in N. benthamiana leaves. The strength of the cell death induced by each construct is shown on the right side. (−) to (+++++) indicate the severity of cell death on a scale of 0 to 5, as shown in Supplemental Figure 2.

(C) and (D) Cell death induced by the full-length NSm or NSm^115–135-YFP in the presence of Sw-5b in wild-type N. benthamiana plants (C) and in tomato (D). Cell death in the infiltrated leaves was photographed at 4 d postinoculation. Expression of NSm^115–135–YFP and YFP in the infiltrated leaves was confirmed by immunoblot assay using YFP antibody (C). The sizes of proteins in kilodaltons are shown to the left of the blot.