Figure 4

Heterologous expression and production of mangotoxin. (A) The mbo operon promoter activity in P. protegens Pf-5 transformed with the mbo operon promoter (pMP::P _mboI ) and with the empty promoter-probe vector pMP220 was used as a control. To check the positive regulation of the mgo operon, the strain Pf-5 was transformed with the vector pLac-mgoBCAD. The result is the average of three independent experiments performed in triplicate. Error bars indicate standard deviation. (B) Mangotoxin production of P. protegens Pf-5 transformed with pLac-mboABCDEF (mbo operon under its own and P _LAC promoter expression), pLac-mboFEDCBA (mbo operon under its own promoter expression) and pLac-mgoBCAD (mgo operon under its own and P _LAC promoter expression) and pMP220-mboABCDEF (mbo operon under its own promoter expression). Data were analysed for significance using a Student’s t-test (P = 0.05). Value of bar with an asterisk designation represent a statistically significant difference to the other bar value.