Figure 8.

Induction of necrosis by BcXYG1 is mediated by two surface-exposed loop motifs. A, Effects of mutations in surface-exposed loops on the necrosis-inducing activity of BcXYG1. N. benthamiana leaves were infiltrated with A. tumefaciens strains expressing constructs with mutations in several different surface-exposed loops. Photographs were taken 5 d after treatment. B, Immunoblot analysis. HA-tagged proteins were detected using anti-HA antibodies. Ponceau S-stained blots show the Rubisco large subunit. C, Diagram of BcXYG2^{NTT134-136GSN GWADG177-181SETGS}-HA in which the BcXYG2 amino acids NTT^134-136 and GWADG^177-181 are substituted by the BcXYG1 amino acids GSN^118-120 and SETGS^157-161, respectively (BcXYG2^{GSN SETGS}). D, Activity assay of BcXYG2^{GSN SETGS}-HA. N. benthamiana leaves were infiltrated with A. tumefaciens carrying the BcXYG2^{GSN SETGS}-HA construct (left) or an empty vector (right). Photographs were taken 5 d after treatment. E, Immunoblot analysis. BcXYG2^{GSN SETGS}-HA was detected using anti-HA antibodies. Ponceau S-stained blots show the Rubisco large subunit.