In this study, we have potentially solved the previously unexplainable phenomenon that P. syringae is the only organism possessing multiple levansucrase-encoding genes. We demonstrated the importance of the upstream region as well as the N-terminus of lscB/C required for the expression of Lsc in P. syringae. The upstream region of lscA does not seem to promote lsc expression. With careful controls, herein we also demonstrated that lscA is not buy LEE011 expressed in other P. syringae pathovars. Methods Bacterial strains, plasmids and growth conditions
Bacterial strains, plasmids and oligonucleotides used in this study are listed in Tables 2 and 3. E. coli DH5α was used as the cloning host  and grown in Lysogeny Broth (LB) medium at 37°C. P. syringae cultures were grown in HSC medium
(0.8 mM MgSO4.7H2O, 30 mM KH2PO4, 16 mM K2HPO4, 2 mM KNO3, 20 μM FeCl3, 19 mM NH4Cl, 100 mM glucose)  at 18°C. Bacterial growth in liquid media was monitored by measuring the optical density at 600 nm (OD600) and harvested for (i) protein sampling at an OD600 of 2.0 or (ii) RNA extraction and check details cDNA synthesis at an OD600 of 0.5 and 2.0. Antibiotics were added to the media at the following click here concentrations (μg ml-1): ampicillin 50; tetracycline 25, and chloramphenicol 25. Table 2 Bacterial strains and plasmids used in this study Strain Description Reference or source Pseudomonas syringae pv. glycinea PG4180 Wild type, levan+ R. Mitchell pv. phaseolicola 1448A Wild type, levan+  pv. syringae B728a Wild type, levan+  pv. tomato DC3000 Wild type, levan+ D. Cuppels Pseudomonas syringae pv. glycinea PG4180 PG4180.M6 Spr, Gmr, lscB lscC mutant of PG4180, levan-  PG4180.M6(pRA3.1) Spr, Gmr, Tcr, lscB lscC mutant of PG4180, containing lscA under control of P lac on 3.1-kb PstI fragment in pRK415  Escherichia coli DH5α supE44 DlacU169 (F80 lacZDM15) hsdR17 recA1 endA1 gyrA96 thi-1 relA1  Plasmids pRK2013 Kmr, helper plasmid
 pLB7.2 Apr, contains lscB on 7.2-kb EcoRV insert  pBBR1MCS Cmr, broad-host-range cloning vector  pBBR1MCS-3 Tcr, broad-host-range cloning vector  pBBR3-500-lscB Tcr, lscB gene with −500-bp upstream sequence in pBBR1MCS-3  pBBR3(lscA) Tcr, lscA gene containing insert from pRA3.1 in PBBR1MCS-3 not under control of P lac This study pBBR3(lscBUpNA) Tcr, Etomidate fusion of 518-bp upstream region of lscB (including first 48-bp of coding region) and lscA (including start codon and downstream region) in pBBR1MCS-3 This study pBBR3(lscBUpA) Tcr, fusion construct of 470-bp upstream region of lscB (without N-terminus) and lscA (including start codon and downstream in pBBR1MCS-3 This study pBBR3(lscAUpB) Tcr, fusion of 550-bp upstream region of lscA and lscB (including start codon and downstream region) in pBBR1MCS-3 This study Ap, Ampicillin; Cm, Chloramphenicol; Gm, Gentamycin; Km, Kanamycin; Sp, Spectinomycin; Tc, Tetracycline; r, resistant.