Virulence factors analysis of native isolates of Xanthomonas albilineans and Xanthomonas sacchari from Tucumán, Argentina, reveals differences in pathogenic strategies.

MIELNICHUK N; BIANCO MI; YARYURA PM; ROMINA PRISCILA BERTANI; LAILA TOUM; DAGLIO Y; COLONNELLA MA; LIZARRAGA L; CASTAGNARO AP; VOJNOV AA

PLANT PATHOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2021 vol. 70 p. 1072 - 1084

0032-0862

Xanthomonasalbilineans (Xa)and X. sacchari (Xs) are both sugarcane pathogens. Xa is thecausalagent of leaf scald disease, but there is limited information about thepathogenicity ofXs. The aimof this work was to study virulence factors of native strains of Xa (Xa32,Xa33,and XaM6)and Xs (Xs14 and Xs15) previously isolated from sugarcane with leaf scaldsymptoms,to gain insight into the biology of each microorganism. We analysed epiphyticsurvival,sensitivity to oxidative stress, extracellular degradative enzymes, cellmotilities,exopolysaccharide(EPS) characteristics, cell adhesion, biofilm development, and control ofstomatalregulation of the five strains. We observed that each species presented similarphenotypesfor every factor analysed. Xa strains appeared to be more sensitive tooxidativestress andpresented lower epiphytic survival than Xs. All strains presented endoglucanaseactivity;however, we could only detect protease and amylase activities in Xs strains.Swimmingand sliding were higher in Xs, but twitching was variable among species. Wealsoobservedthat only Xs strains produced a xanthan-like EPS, presented a strong celladhesion,andstructured biofilm. We detected some intraspecific variations showing thathigheramounts ofEPS produced by Xs14 correlated with its higher sliding motility and itshomogenousand more adhesive biofilm. In addition, EPSs of Xs14 and Xs15 presenteddifferencesin strand height and acetyl percentage. Finally, we found that strains of bothspecieswere able to interfere with stomatal aperture mechanism. All these differencescouldinfluencethe colonization strategies and/or disease progression in each species.