Abstract Wall-associated receptor kinases (WAKs) and WAK-likes (WAKLs) play pivotal roles in regulating plant immunity, through multiple downstream signaling components. However, knowledge of WAKs/WAKLs in wheat immune responses to rust diseases remain limited. In this study, we identified and characterized a wheat WAKL, TaWAKL8-2B , which is upregulated during wheat resistance to both Puccinia striiformis f. sp. tritici ( Pst ) and Puccinia triticina ( Ptt ), indicating its role in wheat resistance to these two rust fungi. Transgenic wheat plants overexpressing TaWAKL8-2B exhibited enhanced resistance to stripe rust and leaf rust, accompanied by increased reactive oxygen species (ROS) production and up-regulated defense-related gene expression. Whereas, knockout TaWAKL8-2B reduced resistance to Pst and Ptt with less ROS accumulation, highlighting its positive role in wheat resistance. RNA-seq analysis revealed that 33 genes encoding ROS-scavenging enzymes were upregulated in TaWAKL8-2B -KO plants, explaining the reduced ROS. KEGG analysis enriched the monoterpenoid pathway, particularly the linalool biosynthesis pathway, with linalool synthases significantly downregulated in TaWAKL8-2B -KO plants. Correspondingly, linalool synthase content and linalool content decreased in knockout plants. Collectively, our findings uncover a novel mechanism by which TaWAKL8-2B positively modulates wheat rust resistance through modulating linalool biosynthesis and peroxidase activity. These results enhance our understanding of TaWAKL8-2B mediated immune signaling and offer a promising gene for improving wheat broad-spectrum resistance to rust diseases.
He et al. (Mon,) studied this question.