Figure 4.

Suppression of basal defences by virulent Xanthomonas campestris pv. vesicatoria in pepper. Mixed inocula of wild‐type and hrp mutant bacteria were infiltrated into leaf mesophyll tissue. The hrp mutant bacteria were tagged with AvrBs3 and identified by immunocytochemistry. The hrp mutants (large arrow) have triggered papilla development (white asterisk) in one cell, but no papilla has formed in the cell in contact with the colony containing wild‐type X. campestris pv. vesicatoria, in which bacteria are embedded in extracellular polysaccharides (small arrow). It is noticeable, however, that chloroplasts have accumulated next to the wild‐type colony. Image kindly provided by Mansureh Keshavarzi; for further details see Keshavarzi et al. (2004).