Molecular study on the carAB operon reveals that carB gene is required for swimming and biofilm formation in Xanthomonas citri subsp. citri

Abstract

BackgroundThe carA and carB genes code the small and large subunits of carbamoyl-phosphate synthase (CPS) that responsible for arginine and pyrimidine production. The purpose of this work was to study the gene organization and expression pattern of carAB operon, and the biological functions of carA and carB genes in Xanthomonas citri subsp. citri. MethodsRT-PCR method was employed to identify the full length of carAB operon transcript in X. citri subsp. citri. The promoter of carAB operon was predicted and analyzed its activity by fusing a GUS reporter gene. The swimming motility was tested on 0.25 % agar NY plates with 1 % glucose. Biofilm was measured by cell adhesion to polyvinyl chloride 96-well plate.ResultsThe results indicated that carAB operon was composed of five gene members carA-orf-carB-greA-rpfE. A single promoter was predicted from the nucleotide sequence upstream of carAB operon, and its sensitivity to glutamic acid, uracil and arginine was confirmed by fusing a GUS reporter gene. Deletion mutagenesis of carB gene resulted in reduced abilities in swimming on soft solid media and in forming biofilm on polystyrene microtiter plates.ConclusionsFrom these results, we concluded that carAB operon was involved in multiple biological processes in X. citri subsp. citri.Electronic supplementary materialThe online version of this article (doi:10.1186/s12866-015-0555-9) contains supplementary material, which is available to authorized users.

Interactions of Salmonella enterica Serovar Typhimurium and Pectobacterium carotovorum within a Tomato Soft Rot

“…The performance of this mutant, which is blocked at an intermediate step in pyrimidine biosynthesis, suggests that pyrimidine biosynthesis is in fact necessary in the soft rot ( 67 ). Although carB plays a role in motility and biofilm formation in Xanthomonas spp., the competitive advantage of the nonmotile mutants that we observed in soft rot suggests that it performs dissimilar functions under the two conditions ( 68 ).…”

Response regulator VemR regulates the transcription of flagellar rod gene flgG by interacting with σ54 factor RpoN2 in Xanthomonas citri ssp. citri

“…The non‐polar deletion mutant ΔvemR was constructed according to the method described previously (Zhuo et al ., ). In brief, the primer pairs vemR1.F/vemR1.R and vemR2.F/vemR2.R were used to amplify the flanking DNA fragments.…”

“…Motility was assessed on 0.3% agar MMX plates as described previously (Zhuo et al ., ). Xcc 29‐1 and the derived mutants were grown in NB medium and suspended in MMX liquid medium at a concentration of OD 600 = 1.0 after centrifugation.…”

Use of Cell Envelope Targeting Antibiotics and Antimicrobial Agents as a Powerful Tool to Select for Lactic Acid Bacteria Strains With Improved Texturizing Ability in Milk Fermentations

“…Interestingly, vancomycin binds to D-alanyl-D-alanine and the active site of CarAB is very similar to that previously described for D-alanine:D-alanine ligase ( Stapleton et al, 1996 ). In addition, carB was found to be the most highly induced gene in a vancomycin sensitive S. aureus strain when grown in the presence of vancomycin ( Awad et al, 2013 ) and has previously been found to be involved in multiple cellular functions including biofilm formation and EPS formation ( Zhuo et al, 2015 ). In STVAN20, we identified four SNPs with two occurring in promoter regions of different genes.…”