These plants were inoculated with X. campestris pv.
musacearum culture in the midrib of the first fully open leaf. The
ontrol nontransgenic plants started to develop symptoms
necrosis or chlorosis) at about 14 dpi and died within 38 dpi,
whereas the six transgenic lines remained healthy for 8 weeks,
onfirming very high resistance. In these plants, slight browning
was observed at the point of inoculation (Fig. 3E) as a result of
he rapid, localized death of plant cells at the site of inoculation.
his is characteristic of the HR response, which is thought to be
n important defence response to prevent further multiplication
nd to restrict the spread of the pathogen to other parts of the
lant (Chen et al., 2000). To confirm this, pathogenic bacteria
were isolated from the pseudostem and inoculated leaves of all
symptomatic transgenic lines tested. The inability to recover
iable bacteria from even the inoculation sites of the transgenic
lants indicated a successful resistance response. One transgenic
ne showed delayed symptoms after 30–35 dpi, indicating
artial resistance. The reduction in wilting was significantly
igher in this line compared with nontransgenic plants. The
acterial population was restricted to the leaf inoculated in this
ne, as bacteria were not recovered from the pseudostem of
hese plants.