The two-component regulator CvsR has a small core regulon <i>in planta</i> and modulates <i>Pseudomonas syringae</i> global gene expression with some overlap to the pattern triggered immunity stimulon response

Pattern-triggered immunity (PTI) provides broad-spectrum protection in plants by activating defense responses upon perception of conserved microbial signatures such as bacterial flagellin. <i>In vitro</i> transcriptome profiling revealed that the <i>Pseudomonas syringae</i> pv. <i>tomato</i> DC3000 two-component regulator CvsR mirrors some of the broader regulatory patterns observed under the exposure to PTI <i>in planta</i>. Our analyses indicated that during infection <i>in planta</i>, CvsR primarily governs a small core regulon centered on carbonic anhydrase and its associated transporter. Comparative RNA-seq analyses between the Δ<i>cvsR</i> and wild type strain further confirm this narrow regulatory scope. Moreover, the majority of bacterial transcriptional shifts appear to reflect indirect consequences of response to the host immune environment rather than direct CvsR-dependent regulation, including responses associated with sulfate starvation. Together, these findings suggest that PTI-driven bacterial transcriptional reprogramming is shaped predominantly by host immune status, with CvsR exerting modest, targeted control restricted to a limited set of genes.