The AP-1 Sigma Subunit Gene PsAP1 Acts as a Key Pathogenicity Factor by Regulating Metabolic Reprogramming in...

Area of Science:

• Plant Pathology
• Molecular Biology
• Fungal Genetics

Background:

• Wheat stripe rust, caused by *Puccinia striiformis* f. sp. *tritici* (Pst), is a major threat to global wheat production.
• The adaptor protein complex AP-1's role in rust fungi is largely unknown, despite its importance in vesicular trafficking.

Purpose of the Study:

• To investigate the function of the AP-1 σ subunit (PsAP1) in Pst pathogenicity.
• To explore PsAP1 as a potential target for controlling wheat stripe rust.

Main Methods:

• Identification and characterization of the PsAP1 gene in Pst.
• Heterologous expression in *Fusarium graminearum* to assess functional complementation.
• Subcellular localization studies.
• Host-induced gene silencing (HIGS) using Barley stripe mosaic virus (BSMV) in wheat.
• Transcriptomic analysis to understand pathway disruptions.

Main Results:

• PsAP1 expression was induced during early Pst infection stages.
• Silencing PsAP1 significantly reduced Pst hyphal growth, sporulation, and pathogen biomass.
• PsAP1 silencing enhanced host reactive oxygen species accumulation and disrupted MAPK signaling, glutathione, and carbohydrate metabolism pathways.
• PsAP1 was localized to the plasma membrane, cytoplasm, and nucleus.

Conclusions:

• PsAP1 is essential for Pst pathogenicity, facilitating infection by modulating vesicular trafficking, suppressing host immunity, and reprogramming host metabolism.
• Targeting PsAP1 offers a promising strategy for developing novel wheat stripe rust control measures.