Coomassie brilliant blue stained gel (a) and western blot (b) of proteins isolated from N. benthamiana plants and separated by SDS-PAGE. M, molecular weight marker (kD); lane 1, total proteins from empty leaves; lane 2, total protein from leaf infiltrated with vector pEff_Flg4M2eHA2-1; lane 3, protein purification on Ni-NTA column: flow-through (unbound) fraction; lane 4, protein purification on Ni-NTA column: washed fraction; lane 5, protein purification on Ni-NTA column: eluate; lane 6, purified Flg4M2eHA2-1 protein after ultracentrifugation (position shown by an asterisk). Positions and sizes of molecular weight markers (kD) are shown in (b) to the left of the image.