Glycogen Synthase Kinase 3 (GSK3) Gene Family in Glycine max Under the Effect of Manganese Stress

Glycogen synthase kinase 3 (GSK3/SHAGGY-like kinase) plays a pivotal role in regulating plant growth, development, and stress responses. To elucidate the characteristics of the GSK family in Glycine max, this study employed whole-genome data combined with bioinformatic and gene expression analyses to investigate the gene structure, chromosomal localization, collinearity, phylogenetic evolution, promoter cis-elements and differential gene expression analysis. Additionally, the expression patterns of GmGSK genes under manganese (Mn) stress and their associated phenotypic alterations were analyzed. A total of 22 GmGSK family members were identified, all harboring the characteristic GSK kinase domain. These members are distributed across 16 chromosomes, encoding proteins ranging from 380 to 802 amino acids (aa) in length. Phylogenetic analysis classified the GmGSK family into four evolutionary clades, consistent with patterns observed in Arabidopsis and Oryza sativa. Members within the same clade share identical exon-intron structures and conserved motifs. Collinearity analysis revealed that segmental duplication events have been crucial in the functional expansion of the GmGSK family through intraspecific collinearity. In recent years, alongside industrial development and fertilizer imbalance, the effective manganese concentration in agricultural soils has risen abnormally in some regions of China, leading to toxic effects on crops. Soybean, an oilseed crop relatively sensitive to manganese, has been adversely impacted. Clarifying the response mechanisms of soybean seedlings to manganese stress is therefore of significant importance for improving both yield and quality. Manganese stress treatment induced significant up-/down-regulation of specific GmGSK members in soybean, concomitant with pronounced inhibition of root elongation and leaf growth. This study provides a theoretical framework for deciphering the molecular regulatory mechanisms by which the GmGSK gene family mediates plant responses to Mn stress, offers insights into soybean Mn tolerance mechanisms, and establishes a foundation for genetic improvement of Mn-tolerant traits in crops.