Chloroplast-to-apoplast relocalization of MOC1 strengthens plant vascular immunity

Abstract

Pathogenic bacteria deploy biofilm as a key virulence factor to cause plant vascular diseases, which are devastating to global agricultural practices. Extracellular DNA (eDNA) constitutes the backbone of bacterial biofilm and is key to biofilm stability, thereby representing as an attractive therapeutic target. Here, we engineered the plant chloroplast-localized Holliday junction (HJ) resolvase MOC1 by replacing its native chloroplast transit peptide with a secretory signal, successfully relocating it to the apoplast. Transgenic tomato and rice expressing secreted MOC1 exhibited robust resistance to bacterial wilt and bacterial blight, respectively, without growth or yield penalties. Additionally, we implemented bacterial pathogen-inducible promoters to achieve precisely spatial and temporal control over the resistance trait. Secreted MOC1 degrades eDNA in situ, disrupts biofilm architecture, and markedly reduces bacterial colonization and systemic spread. Our work presents a novel strategy for controlling vascular diseases by engineering plant HJ resolvases to disrupt biofilms. This approach provides a new blueprint for molecular resistance breeding and disease resistance gene exploration.

Acknowledgements

We thank Prof. J. Zhou and Prof. S. Ding for constructive discussion and suggestions for this research. We are grateful to Prof P. Yin and J. Yan for sharing the plasmid vectors. The study was supported by National Natural Science Foundation of China (32472512) and Fundamental Research Funds for the Central Universities (2662025ZKPY008), Hubei Special Project for Science Development (2024CSA060), and Funds of the National Key Laboratory of Agricultural Microbiology (AML2023C01).

Author contributions

X.Y. and B.L. designed the experiments. X.D. generated transgenic plants material, performed the microscopic imaging, disease infection, and drafted the manuscript. Y.J.Liu generated vectors and transgenic tomato. S.Y. designed the rice promoter and constructed transgenic rice. P.L. cloned the tomato promoter and tested activity, Y.S.Liu helped with the rice leaf blight disease assay. M.Y., J.X., Y.Lin., J.C., Y.F., and D.J. analyzed data and provided critical feedback. X.Y. and B.L. wrote the paper with input from all authors.

Data availability

All the data supporting the findings of this study are included in this article or as supporting information.

Conflicts of interest statement

The authors declare no conflicts of interest.

Supplementary material

Supplementary material is available at Horticulture Research online.

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