770 (2002) 275–281 Journal of Chromatography B, www.elsevier.com / locate / chromb Identification of xanthans isolated from sugarcane juices obtained from scalded plants infected by Xanthomonas albilineans a, b c a * ˜ ´ ´ Blanca Fontaniella , C.W. Rodrıguez , Dolores Pinon , C. Vicente , a ´ Marıa-Estrella Legaz a Laboratory of Plant Physiology, Faculty of Biology, Complutense University, 28040 Madrid, Spain b Department of Plant Biology, Faculty of Biology, Havana University, Havana, Cuba c National Institute of Sugarcane Research, Havana, Cuba Abstract The exudate gum produced by Xanthomonas albilineans, a specific sugarcane pathogen, has been isolated from juices of diseased sugarcane stalks, hydrolyzed with hydrochloric acid, and the hydrolysate analyzed by capillary electrophoresis. Sucrose, cellobiose, mannose, glucose, glucose-1-P and glucuronic acid were identified as the major components of the polysaccharide isolated from diseased stalks. Juices from healthy stalks contained maltose instead of cellobiose. The chemical nature of this polysaccharide is discussed.  2002 Elsevier Science B.V. All rights reserved. Keywords: Xanthomonas albilineans; Xanthans 1. Introduction vessels in both leaves and stalks by producing a gum which seems to be similar to xanthans [2]. As a Xanthomonas albilineans, a specific sugarcane consequence, a severe water stress appears as the phytopathogen, produces a disease defined as leaf main symptom of the disease in infected plants. scald. The initial characteristic symptom is a white During the first stages of the bacterial infection, streak (‘pencil-line’) 1–2 mm wide on the leaf which sugarcane plants increase the production of glycopro- follows the direction of the main veins. The streaks teins containing a heterofructan as glycosidic moiety may later become more enlarged and the affected as a defense mechanism [3]. Thus, bacterial gum and leaf becomes wilted and necrotic. The white pencil plant heterofructans coexist during this period. The line may also be visible on the leaf sheaths. Symp- chemical nature of this gum has not yet been studied toms of this phase are seen after ratooning or in although another pathogenic species of Xanthomonas young shoots growing from infected plant cane. produces a gum known as xanthan. Later, these symptoms may disappear, although Xanthan is an industrially important exopolysac- plants remain infected [1]. Alternatively, plants may charide produced by the phytopathogenic, Gram- be infected, but grow without showing any symp- negative bacterium Xanthomonas campestris pv. toms. Mature stalks may suddenly wilt and die, campestris. It is composed of polymerized pentasac- sometimes without the previous appearance of other charide repeating units which are assembled by the symptoms. X. albilineans induces closing of xylem sequential addition of glucose-1-phosphate, glucose, mannose, glucuronic acid, and mannose on a poly- *Corresponding author. prenol phosphate carrier [4]. The polymerization of 1570-0232 / 02 / $ – see front matter  2002 Elsevier Science B.V. All rights reserved. PII: S1570-0232(01)00579-7