Hydrogen sulfide promotes wheat immunity against stripe rust through TaATG6c persulfidation

Abstract Hydrogen sulfide (H 2 S) is a key gaseous signaling molecule involved in plant growth and stress responses, yet its role in wheat resistance to stripe rust remains poorly understood. Here, we show that exogenous H 2 S enhances resistance of wheat ( Triticum aestivum L.) to Puccinia striiformis f. sp . tritici ( Pst ), the causative agent of stripe rust. Comparative persulfidation proteomics identified the autophagy-related protein TaATG6c as a Pst -responsive H₂S target. Site-specific mass spectrometry and a modified biotin-switch assay demonstrated that Cys177 and Cys180 of TaATG6c undergo H₂S-induced persulfidation. Structural modeling based on AlphaFold predicted that these two site mutations reduced the binding activity of ATG6c to ATG14. Functional characterization using virus-induced gene silencing (VIGS) revealed that TaATG6 positively regulates wheat immunity against Pst , as silencing TaATG6 promoted fungal growth. Moreover, TaATG6 expression was markedly induced during Pst infection. Notably, the resistance-promoting effect of NaHS was compromised in TaATG6 -silenced plants. Conversely, transient overexpression of TaATG6 enhanced wheat resistance to stripe rust, whereas mutation of Cys177 and Cys180 attenuated this effect. Endogenous biotin-switch assays further showed that TaATG6c persulfidation exhibits pathogen-responsive and dynamic characteristics, which were abolished in the TaATG6 C177A/C180A mutant. Consistently, H₂S treatment and Pst infection stimulated the accumulation of lipidated ATG8 (ATG8–PE), indicating activation of autophagy, while this response was largely abolished in TaATG6 -silenced plants. Together, these results suggest that H₂S promotes autophagy initiation through persulfidation of TaATG6c, thereby enhancing wheat resistance to stripe rust and highlighting a redox-regulated mechanism underlying plant stress adaptation.