All 12 isolates and the type strain wereinoculated into three citrus species: grapefruit(Citrus × paradisi), key lime (C. aurantiifolia), and sweet orange (C. sinensis).
These plants were 2 years of age and had
been produced and maintained in greenhouse
conditions. Various inoculation
methods were evaluated, including spraying
with and without wounding, needle
puncturing, and pressure infiltrating by
tuberculin syringes into newly expanded
leaves on new flushes of all three citrus
species. The concentration of inocula
ranged from 108
to 103
CFU/ml with one
log intervals. The concentrations of 108
,
107
, and 106
CFU/ml were chosen for infiltration
studies and for histology. Samples
eliciting different symptoms from inoculated
citrus were collected, and the inoculated
bacteria were reisolated in order to
verify that the elicited symptoms were
consistent. Inoculation controls included a
citrus canker strain (Xanthomonas citri pv.
citri), a citrus bacterial spot strain (Xanthomonas
axonopodis pv. citrumelo),