<p>Cellulose synthase-like proteins (CSLs), members of the cellulose synthase superfamily, remain relatively poorly characterized in terms of their substrate specificity and function, despite their importance in plant development. It is hypothesized that CSLs are involved in the biosynthesis of the backbone of hemicelluloses, which are key components of plant cell walls in various tissues. The characteristics of cell walls in different plant tissues may be determined by specific CSL isoforms. In celery, petiole tissues contain pectin-enriched primary cell walls formed by parenchyma and collenchyma cells, while vascular bundles contain secondary cell walls in vessels, alongside cells with primary cell walls. In the current work, phylogenetic and expression analyses of the <i>CSL</i> genes in different celery tissues were conducted. A set of <i>AgrCSLA</i> and <i>AgrCSLC</i> genes, encoding glycosyltransferases involved in mannan and xyloglucan biosynthesis, respectively, was found to be upregulated in growing collenchyma. In vascular bundles, however, a distinct set of <i>AgrCSLA</i> and <i>AgrCSLC</i> genes was upregulated. This difference in the gene sets involved in mannan and xyloglucan biosynthesis may contribute to structural differences in these polysaccharides and/or variations in the regulation of glycosyltransferase gene expression. Additionally, some genes encoding AgrCSLB, AgrCSLE, and AgrCSLG members were specifically upregulated in different tissues, including parenchyma. The substrate specificities of these genes remain unestablished. However, coexpression analysis of these genes and their expression in other plant tissues suggests that some of the CSL proteins encoded by these genes may be associated with pectin biosynthesis or protein glycosylation.</p> Graphical abstract <p></p>