Identification of LsPROG gene in Leymus secalinus and validation of its function in Arabidopsis thaliana

Leymus secalinus, a perennial grass in the Poaceae family, exhibits multiple stress resistances including drought, salt-alkali, and trampling tolerance, with developed rhizomes enabling adaptation to harsh environments such as sand dunes, thus holding significant value for grassland improvement and forage breeding.

This study functionally characterized the stress-related LsPROG gene of L. secalinus, revealing that it encoded a 184-amino acid protein. Subcellular localization showed that it was localized to the cell membrane, and contained a conserved zinc-finger domain indicative of potential transcriptional regulatory functions. Using Arabidopsis as a heterologous system, we generated 35S:LsPROG overexpressing Arabidopsis lines. In Arabidopsis transgenic lines, we confirmed that LsPROG significantly promoted lateral root development (about 2-fold) and significantly increased leaf number (by about 1.5-fold at the seedling stage) in transgenic lines compared to the Col-0. Notably, under drought, salt (NaCl), and ABA stresses, the 35S:LsPROG transgenic lines exhibited significantly even more pronounced phenotypic advantages over the Col-0 including improved root system development in seedlings (specifically higher lateral root numbers under drought and enhanced primary root growth under salt/ABA) and better overall plant growth, accompanied by significantly enhanced activities of antioxidant enzymes (SOD increased by 35%, POD increased by 40%).

Through heterologous expression in Arabidopsis, this study systematically unveiled for the first time the pivotal role of LsPROG in plant growth, development, and stress responses, with its functional characteristics elucidated via cross-validation with multiple experimental approaches. These findings lay a critical theoretical foundation for the future breeding of high-quality forage varieties.