snRNA-Seq Unveils Cell-Type-Specific Immune Dynamics in Arabidopsis During Pinewood Nematode Infection

The alterations in gene expression levels in response to the pathogens are pivotal in determining pathogenicity or susceptibility. However, the cell-type-specific interaction mechanism between the pinewood nematode (PWN) and its hosts remains largely unexplored and poorly understood. Here, we employed single-nucleus RNA sequencing (snRNA-seq) with PWN-infected Arabidopsis leaves to dissect the heterogeneous immune responses. We identified four major cell types, each exhibiting distinct immune responses during infection by PWNs. Subcluster analyses uncovered dynamic shifts in immune-active subpopulations within mesophyll and epidermal cells. Notably, AtWRKY70 positively regulated plant defence against PWNs by suppressing the promoter activity of AtPNP-A in a salicylic acid-dependent manner. This study not only provides novel mechanistic insights into plant gene regulation during PWN infection, but also offers feasible references for future investigations of host-PWN interactions, with particular relevance to the identification of pine tree resistance genes against this pathogen.