Cell wall-mediated root development is targeted by a soil-borne bacterial pathogen to promote infection

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Plant pathogens manipulate host development, facilitating colonization and proliferation. Ralstonia solanacearum is a soil-borne bacterial pathogen that penetrates roots and colonizes plants through the vascular system, causing wilting and death. Here, we find that RipAC, an effector protein from R. solanacearum, alters root development in Arabidopsis, promoting the formation of lateral roots and root hairs. RipAC interacts with CELLULOSE SYNTHASE (CESA)-INTERACTIVE PROTEIN 1 (CSI1), which regulates the activity of CESA complexes at the plasma membrane. RipAC disrupts CESA-CSI1 interaction, leading to a reduction in cellulose content, root developmental alterations, and a promotion of bacterial pathogenicity. We find that CSI1 also associates with the receptor kinase FERONIA, forming a complex that negatively regulates immunity in roots; this interaction, however, is not affected by RipAC. Our work reveals a bacterial virulence strategy that selectively affects the activities of a host target, promoting anatomical alterations that facilitate infection without causing activation of immunity.

This work was supported by the National Natural Science Foundation of China (NSFC; grants 32270284 to G.Y. and 32170289 to A.P.M.), the Strategic Priority Research Program of the Chinese Academy of Sciences (grant XDB27040204 to A.P.M.), the Spanish Government/MCIN/AEI/10.13039/501100011033 (BIO2017-82209-R to J.C.d.P.), the Initiative Center of Excellence for Plant Environment Interactions (CEPEI) in the frame of the Severo Ochoa Program for Centers of Excellence in R&D (grants SEV-2016-0672 and CEX-2020-000999-S) funded by MCIN/AEI/10.13039/501100011033 and by “ESF Investing in your future,” the Chinese 1000 Talents Program (to A.P.M.), and the Shanghai Center for Plant Stress Biology (Chinese Academy of Sciences).

Peer reviewed