Xanthomonas albilineans, a pathogenic bacterium that produces leaf scald disease of sugarcane,
secretes a xanthan-like gum that invades both xylem and phloem of the host. Xanthan production
has been verified after experimental infection of stalk segments of healthy plants. Moreover,
Gluconacetobacter diazotrophicus is a nitrogen-fixing endosymbiont of sugarcane plants that antagonizes
with X. albilineans by impeding the production of the bacterial gum. The physiological
basis of this antagonism has been studied using tissues of sugarcane stalks previously inoculated
with the endosymbiont, then immobilized in calcium alginate and maintained in a culture medium
for Gluconacetobacter. Under these conditions, bacteria infecting immobilized tissues are able to
secrete to the medium a lysozyme-like bacteriocin that inhibits the growth of X. albilineans.