[21], in which pvf and gac mutants were complemented by a wild-type extract. These results allow us to propose a putative regulatory role for the mgo operon in secondary metabolite production by P. syringae pv. syringae, in accordance with Vallet-Gely et al. [21]. To fully

characterise the functions of the mgo operon, more data concerning the chemical structure of mangotoxin and a characterisation of the other genetic traits that regulate mangotoxin biosynthesis by P. syringae pv. syringae UMAF0158 are required. PLX4032 Dibutyryl-cAMP mouse Conclusions In the present study, the organisation of the mgo operon in P. syringae pv. syringae UMAF0158 was characterised. The mgo operon is composed of four genes, mgoB, mgoC, mgoA and mgoD. Additionally, this operon possesses one active promoter and a terminator. The last three genes are essential for mangotoxin production, as insertional mutation of these genes results in a loss of mangotoxin production. This operon is only active in minimal medium, in agreement with the standard process for mangotoxin production.

Moreover, experiments performed to determine 4-Aminobutyrate aminotransferase the functional role of the mgo operon demonstrated a putative regulatory function in the production of mangotoxin. Methods Bacterial strains and plasmids used in this study The strains of Escherichia coli, Caspase Inhibitor VI supplier Pseudomonas fluorescens Pf-5 and Pseudomonas syringae pv. syringae as well as the vectors and plasmids used in this study are listed in Table 5. E. coli was grown in Luria-Bertani

medium (LB) at 37°C for 24 h. The Pseudomonas strains were grown routinely in King’s medium B (KB) at 28°C for 48 h. Derivative mutants of P. syringae pv. syringae UMAF0158 (Table 5) were grown and maintained in KB supplemented with the appropriate antibiotics (ampicillin, 50 μg/ml; streptomycin, 50 μg/ml; kanamycin, 50 μg/ml; and gentamicin, 20 μg/ml). Table 5 Bacterial strains and plasmids used in this study Strain or plasmid Relevant characteristicsa Reference or source Escherichia coli        DH5α recA lacZΔM15 [27]    CECT831 Indicator strain of mangotoxin production CECTb Pseudomonas fluorescens        Pf-5 Complete genome sequenced and free access. [28] Pseudomonas syringae pv.