Dandan Huang

Hainan Institute of Biotechnology, Haikou, 570206, Hainan, China
Author    Correspondence author
Legume Genomics and Genetics, 2025, Vol. 16, No. 5   
Received: 03 Jul., 2025    Accepted: 20 Aug., 2025    Published: 05 Sep., 2025

This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Expansins are plant-specific proteins that play crucial roles in cell wall loosening and are essential for various developmental processes and stress responses. This study comprehensively analyzes the expansin gene family in legumes, focusing on its structural diversity, evolutionary patterns, expression dynamics, and functional relevance. We classify expansins into α-expansin, β-expansin, and expansin-like A and B subfamilies and discuss their gene duplication events, chromosomal localization, and conserved domain structures in major legume species. Phylogenetic relationships and Ka/Ks ratio analyses provide new insights into their evolutionary trajectories and selective pressures. Furthermore, we investigate tissue-specific and developmental stage-specific expression patterns, highlighting the roles of expansins in root growth, nodulation, and pod formation. Expression profiles under various abiotic and biotic stress conditions reveal their involvement in stress adaptation mediated by hormone signaling pathways. Functional studies involving gene overexpression, gene knockout, and omics-based analyses highlight their contributions to cell expansion, stress tolerance, and the regulation of root system architecture. A case study focusing on soybean illustrates how differential expression and transgenic validation of expansin genes influence drought resistance and nodulation. This study lays the foundation for understanding the functions of expansin genes in legumes and provides prospects for their application in molecular breeding, genome editing, and improving stress tolerance in legume crops.

Expansin proteins; Legumes; Gene expression dynamics; Evolutionary analysis; Stress response