Virulence hierarchical regulatory network reveals 35 TFs involved in virulence.
a, Virulence hierarchical regulatory network shows the TF hierarchy and the large pool of target genes of multi-TF. Target genes are related with seven key virulence pathways, including biofilm formation, secondary messengers, motility, T3SS, QS, phytotoxin production and siderophore transporter. Orange nodes represent top TFs. Green nodes represent middle TFs. Purple nodes represent bottom TFs. Blue nodes represent target genes. Yellow edges represent downward point. Red edges represent upward point. b, The head-to-head binding motif of PSPPH1951, the validation of the binding sites of PSPPH1951 by EMSA, and the detection of expression of target gene hopAE1 in WT, ΔPSPPH1951 and complementary strain by RT-qPCR. The validated binding sites are from the promoters of the hrpR, hopAE1 and hopAH2. c, The binding motif of PSPPH2193 is head-to-head. EMSA confirms the direct binding of PSPPH2193 to the promoters of fleQ and flhF. RT-qPCR confirms the positive regulation of PSPPH2193 on the expression of fleQ and flhF. Motility assay validates the weaker motility of ΔPSPPH2193 than WT and complementary strain. d, The binding motif of PSPPH3268 is head-to-head. EMSA confirms the direct binding of PSPPH3268 to the promoters of hrpR, alg44 and pilM. RT-qPCR confirms the negative regulation of PSPPH3268 on the expression of alg44, algX and pilM. Crystal violate staining assay and the quantification of biofilm formation validate the negative regulation of PSPPH3268 on the biofilm formation. Congo red assay confirms the negative regulation of PSPPH3268 on colony morphologies and EPS production. Student’s t test. n.s., not significant, *P ≤ 0.05, **P ≤ 0.01, and ***P ≤ 0.001.