Genome-wide identification and expression analysis of the pectate lyase (PEL) gene family in soybean (Glycine max (L.) Merr. ).

Pectate lyases (PELs) are important enzymes involved in the regulation of plant cell wall structure and composition and play essential roles in plant growth and development. However, the characteristics and potential functions of the PEL gene family in soybean remain largely unclear. In this study, a total of 38 GmPEL genes were identified from the soybean genome through genome-wide analysis and classified into five evolutionary groups. Evolutionary analyses indicated that segmental duplication was the major driving force underlying the expansion of the GmPEL family, which has undergone strong purifying selection during evolution. Cis-acting element and expression profile analyses suggested that GmPEL genes are widely involved in plant growth, development and stress responses. Notably, members of Group II exhibited relatively high expression levels in floral tissues and showed significant downregulation in the flower buds of cytoplasmic male sterility (CMS) lines, while their expression levels were responsive to high-temperature (HT) stress during flowering. Subcellular localization analysis further demonstrated that GmPEL3, GmPEL12, GmPEL23, and GmPEL34 are localized to the endoplasmic reticulum. These results suggest that Group II genes may participate in flower development, fertility regulation and HT stress responses in soybean. Overall, this study provides a comprehensive characterization of the soybean PEL gene family and offers candidate genes for further investigation of reproductive development and stress tolerance in soybean.