Plant physiologyFeb 20, 2025

The wheat stripe rust protein PstEXLX1 blocks an enzyme to weaken wheat's immune defense

CRISPR Gene Editing Weekly Brief ↗PubMed ↗DOI ↗

Updated Mar 5, 2026

Abstract

The expansin-like protein 1 from Puccinia striiformis (PstEXLX1) is associated with enhanced virulence in wheat by inhibiting host immune responses.

PstEXLX1 suppresses cell death in Nicotiana benthamiana.
Knockdown of PstEXLX1 reduces Pst development in wheat.
Overexpression of PstEXLX1 enhances Pst virulence through inhibition of pathogen-triggered immunity.
PstEXLX1 stabilizes itself and associates with the wheat protein TaFDH1.
Wheat lines overexpressing TaFDH1 show increased resistance to Pst due to higher catalytic activity and defense responses.
PstEXLX1 inhibits TaFDH1 activity, which is lessened in plants where PstEXLX1 is silenced.

Simplified

Effectors are the most critical weapons that Puccinia striiformis f. sp. tritici (Pst) employs to engage with wheat (Triticum aestivum L.). Discovering important effectors is essential for deciphering the pathogenic mechanisms of Pst. In this study, we identified the expansin-like protein 1 from Pst (PstEXLX1), which suppresses cell death in Nicotiana benthamiana. In wheat, knockdown of PstEXLX1 diminished Pst development, whereas PstEXLX1 overexpression enhanced Pst virulence by inhibiting pathogen-associated molecular pattern-triggered immunity, indicating its importance in pathogenesis. Further investigation revealed that PstEXLX1 stabilizes itself through self-association mediated by its expansin-like domain, which also determines its association with the wheat formate dehydrogenase (FDH) TaFDH1. Wheat lines overexpressing TaFDH1 exhibited increased resistance to Pst, which was associated with elevated TaFDH1 catalytic activity and induced defense responses. In addition, TaFDH1 activity was strongly inhibited in the presence of PstEXLX1 but became more robust in PstEXLX1-silenced plants, suggesting that PstEXLX1 suppresses TaFDH1 activity. Collectively, our results uncover a strategy employed by Pst to facilitate infection, wherein PstEXLX1 suppresses TaFDH1 activity to repress host immune responses.

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Conflict of interest statement. None declared.

PubMed

The wheat stripe rust protein PstEXLX1 blocks an enzyme to weaken wheat's immune defense

Abstract

Full Text

Funding

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Abstract

Full Text

Funding

Competing interests

Related papers

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Recent issues from the crispr gene editing brief