Figure 4

Complementation assay.
(a) ClpV is an essential component of T6SS. T6SS activity was detected by western blotting using VgrG antibody from culture supernatants and cell lysates of wild-type, clpV::Tn5 and clpV::Tn5/clpV. The level of RpoA, which was used as a loading control, was detected by western blotting in cell lysates with a specific antibody. (b) Overexpression of ClpV in clpV::Tn5 mutant is able to complement pyoverdine secretion. The complemented vector pCPP30 harboring a clpV fragment was analyzed for pyoverdine secretion in the clpV::Tn5 mutant by MALDI-IMS. MALDI-IMS imaging of pyoverdine from incubation of wild-type, clpV::Tn5 mutant and clpV::Tn5/clpV P. taiwanensis with Xoo were monitored.