Stripe rust fungi hijack a host transcriptional repressor to induce TaSWEET14d for enhanced sugar uptake in wheat.

Abstract

Biotrophic pathogens rely on host plants for carbon acquisition, making plant sugar transporters, such as Sugars Will Eventually be Exported Transporters (SWEETs), key targets in sugar competition between plants and pathogens. In this study, we identified <i>TaSWEET14d</i> as a <i>Puccinia striiformis</i> f. sp. <i>tritici</i> (<i>Pst</i>)-induced, secretory vesicle-localized SWEET family member that facilitates hexose and sucrose translocation in wheat. Knockout of <i>TaSWEET14d</i> led to enhanced wheat resistance to <i>Pst</i>, while overexpressing <i>TaSWEET14d</i> promoted susceptibility to stripe rust and sugar accumulation in wheat leaves. In addition, wheat transcription factor TaMYB50 contributed to stripe rust resistance by suppressing <i>TaSWEET14d</i> expression through binding directly to the TA-box motif in the promoter region. Furthermore, we found that effector protein Pst15882, required for <i>Pst</i> infection and pathogenicity, interacted with TaMYB50 to prevent this repression, thus revealing a distinctive regulation strategy by <i>Pst</i> to exploit host sugars for fungal invasion.