Ralstonia solanacearum effector RipAF1 ADP-ribosylates host FBN1 to induce resistance against bacterial wilt

Abstract

Ralstonia solanacearum (Rso) causes destructive bacterial wilt across a broad range of host plants by inducing jasmonic acid (JA) signaling while suppressing salicylic acid (SA) signaling pathways during disease development. In the present study, we show that Rso type III effector RipAF1 exerts a negative effect on bacterial virulence by subverting disease signaling in association with bacterial wilt. The ADP-ribosylation activity of RipAF1 was verified both in vivo and in vitro. Host fibrillin FBN1 was identified as a RipAF1-interacting protein that acted as a susceptible factor for bacterial wilt. In particular, RipAF1 directly ADP-ribosylates FBN1 at the E175/K207 residues, thus interfering with the mediation of disease signaling by FBN1. Together, these results suggest that RipAF1 exerts a role in defense induction by ADP-ribosylation of the susceptible factor FBN1 in the host plant.