The plant-specific transcription factors CBP60g and SARD1 are targeted by a Verticillium secretory protein VdSCP41 to modulate immunity

Abstract

The vascular pathogen <i>Verticillium dahliae</i> infects the roots of plants to cause <i>Verticillium</i> wilt. The molecular mechanisms underlying <i>V. dahliae</i> virulence and host resistance remain elusive. Here, we demonstrate that a secretory protein, VdSCP41, functions as an intracellular effector that promotes <i>V. dahliae</i> virulence. The <i>Arabidopsis</i> master immune regulators CBP60g and SARD1 and cotton GhCBP60b are targeted by VdSCP41. VdSCP41 binds the C-terminal portion of CBP60g to inhibit its transcription factor activity. Further analyses reveal a transcription activation domain within CBP60g that is required for VdSCP41 targeting. Mutations in both <i>CBP60g</i> and <i>SARD1</i> compromise <i>Arabidopsis</i> resistance against <i>V. dahliae</i> and partially impair VdSCP41-mediated virulence. Moreover, virus-induced silencing of <i>GhCBP60b</i> compromises cotton resistance to <i>V. dahliae</i>. This work uncovers a virulence strategy in which the <i>V. dahliae</i> secretory protein VdSCP41 directly targets plant transcription factors to inhibit immunity, and reveals CBP60g, SARD1 and GhCBP60b as crucial components governing <i>V. dahliae</i> resistance.