Figure 8.

A working model illustrating Lon‐mediated virulence regulation and its interaction with Rcs and Gac‐Csr regulatory systems in Erwinia amylovora. This model is based on findings obtained in this study as well as those reported in previous studies (Ancona et al., 2014; 2015a, 2015b, 2016; Lee and Zhao, 2016; Lee et al., 2016; Li et al., 2014; Wang et al., 2009, 2012; Zhao et al., 2009a). FlhD/C, master regulator of flagellar formation; HrpL, an exocytoplasmic functions (ECF) sigma factor and master regulator of the type III secretion system (T3SS); HrpS, σ⁵⁴‐dependent enhancer‐binding protein; IHF, integration host factor; RpoN, σ⁵⁴ alternative sigma factor; YhbH, σ⁵⁴ modulation protein (ribosome‐associated protein); RNAP, RNA polymerase; (p)ppGpp, guanosine tetraphosphate and guanosine pentaphosphate; GacS/GacA and RcsA/B/C/D, two‐component regulatory systems; csrB, small non‐coding regulatory RNA; CsrA, RNA‐binding protein; OM, outer membrane; IM, inner membrane; P, phosphorylation. Symbols: ↓, positive effect; ⊥, negative effect; dashed line with/without ?, unknown mechanism.