T6SS expression and Hcp secretion are positively regulated by ChvG/ChvI and negatively regulated by ExoR.

<p><i>A. tumefaciens</i> wild-type strain C58, <i>ΔchvG</i>, <i>ΔchvI</i>, <i>ΔexoR</i>, and <i>ΔchvG ΔexoR</i> mutant strains grown in AB-MES (pH 7.0) at 25°C for 6 h were analyzed for T6SS expression and secretion. (<b>A</b>) Total proteins were analyzed by western blot analysis with antibodies against C-IcmF, Fha1 (filled arrow), Atu4343, ClpV, Hcp, Atu4349, and RpoA. (<b>B</b>) Total (T) and secreted (S) proteins were analyzed by western blot analysis with antibodies against Hcp and RpoA. The non-secreted protein RpoA was an internal control. The positions of molecular mass markers (in kDa) are indicated on the left. (<b>C</b>) qRT-PCR analysis of mRNA levels of indicated genes. Data are mean ± SD of 2 biological replicates, each of which contains 3 technical replicates.