Figure 6. A working model illustrated the role of the RNA-binding protein CsrA in Erwinia amylovora.

This model is based on findings obtained in this study as well as those reported in previously studies⁷,⁸,⁹,¹⁰,¹³,¹⁴,⁵⁰,⁶⁰. FlhDC: master regulator of flagellar formation; HrpL: an ECF sigma factor and master regulator of T3SS; HrpS: a σ⁵⁴-dependent enhancer binding protein; Ihfα/β: integration host factor αβ; RpoN: a σ⁵⁴ alternative sigma factor; YhbH: σ⁵⁴ modulation protein (ribosome-associated protein); RNAP: RNA polymerase. (p)ppGpp: guanosine tetraphosphateand guanosine pentaphosphate; GrrS/GrrA; RcsABCD: 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; dash line with/without ?: unknown mechanism.