Sugarcane glycoproteins are required to the production of an active UDP-glucose dehydrogenase byXanthomonas albilineans

Abstract

In vitro enzymatic assay of UDP-glucose dehydrogenase from Xanthomonas albilineans requires the addition of a protease inhibitors cocktail to cell-free extracts, since bacterial proteases rapidly hydrolyses the enzyme in solution. The addition of low amounts of 8-azaguanine and chloramphenicol to the culture medium do not impede the production of the dehydrogenase that requires concentrations higher than 0.3 mM of both antimetabolites to inhibit its synthesis. Glycoproteins from sugarcane, the natural host of the bacterium, also assure the production of the active enzyme by inhibiting bacterial proteases.

Xanthan production by Xanthomonas albilineans infecting sugarcane stalks

“…Thus, it can be concluded that X. albilineans invading the storage tissue of sugarcane stalks is able to produce xanthans that can be conveniently separated from sugarcane polysaccharides. This could be explained on the basis of the action previously found of bacterial protease inhibition caused by sugarcane polysaccharides in such a way that a non-proteolyzed, active UDP glucose dehydrogenase would assure xanthan production (Blanch et al, 2007b). Figure 9.…”

Sugarcane glycoproteins may act as signals for the production of xanthan in the plant-associated bacteriumXanthomonas albilineans

“…16 The polysaccharide moieties of these glycoproteins are composed of a β-1,2-fructosyl fructofuranoside linked to galactitol units through an ether bond. 17,18 It has been proposed near the xylem displayed long, polar flagella identical to those observed in Xanthomonas (Fig. 4A); however, this fact alone is not proof of the unequivocal identity of the genus.…”

Defense Proteins from Sugarcane Studied by Conventional Biochemical Techniques, Genomics and Proteomics: An Overview

“…This polysaccharide, unlike what happens with X. campestris [24], is only produced when bacteria infect the cane plant and is used to plug the phloem and xylem elements, which induces leaf drying. Blanch et al [25] demonstrated that sensitive sugarcane cultivars produce, after being infected, glycoproteins that act as inhibitors of these bacterial proteases in such a way that UDPG dehydrogenase remains intact and active and xanthan can be produced. It is likely that this host-pathogenic interdependence is probably derived from a coevolution process.…”