Sucrose nonfermenting 2 (Snf2) family proteins are the core component of chromatin remodeling complexes that can alter chromatin structure and nucleosome position by utilizing the energy of ATP, playing a vital role in transcription regulation, DNA replication, and DNA damage repair. Snf2 family proteins have been characterized in various species including plants, and they have been found to regulate development and stress responses in Arabidopsis. Soybean (Glycine max) is an important food and economic crop worldwide, unlike other non-leguminous crops, soybeans can form a symbiotic relationship with rhizobia for biological nitrogen fixation. However, little is known about Snf2 family proteins in soybean. In this study, we identified 66 Snf2 family genes in soybean that could be classified into six groups like Arabidopsis, unevenly distributed on 20 soybean chromosomes. Phylogenetic analysis with Arabidopsis revealed that these 66 Snf2 family genes could be divided into 18 subfamilies. Collinear analysis showed that segmental duplication was the main mechanism for expansion of Snf2 genes rather than tandem repeats. Further evolutionary analysis indicated that the duplicated gene pairs had undergone purifying selection. All Snf2 proteins contained seven domains, and each Snf2 protein had at least one SNF2_N domain and one Helicase_C domain. Promoter analysis revealed that most Snf2 genes had cis-elements associated with jasmonic acid, abscisic acid, and nodule specificity in their promoter regions. Microarray data and real-time quantitative PCR (qPCR) analysis revealed that the expression profiles of most Snf2 family genes were detected in both root and nodule tissues, and some of them were found to be significantly downregulated after rhizobial infection. In this study, we conducted a comprehensive analysis of the soybean Snf2 family genes and demonstrated their responsiveness to Rhizobia infection. This provides insight into the potential roles of Snf2 family genes in soybean symbiotic nodulation.

Serine acetyltransferase (SAT) is a critical enzyme in the sulfur-assimilation pathway of cysteine, playing an essential role in numerous physiological functions in plants, particularly in their response to environmental stresses. However, the structural characteristics of the soybean SAT gene family remain poorly understood. Members of the soybean SAT gene family were identified using the Hidden Markov Model approach. Bioinformatics tools, such as ExPASy, PlantCARE, MEME, and TBtools-II, were employed to examine the physicochemical properties, cis-regulatory elements, conserved motifs, gene structures, and chromosomal positions of the GmSAT genes. RT-qPCR was conducted to evaluate the expression profiles of GmSAT genes under NaCl-induced stress, identifying genes likely involved in the salt-stress response. A total of ten GmSAT genes were identified in the soybean genome and grouped into three subfamilies. Genes within each subfamily shared notable structural similarities and conserved motifs. Analysis of cis-regulatory elements revealed that the promoters of these genes contain several elements linked to plant growth and stress-related responses. Expression patterns of GmSAT genes varied across different soybean tissues, with GmSAT10 showing higher expression in roots, while GmSAT1 and GmSAT2 had lower expression in the same tissue. Following NaCl treatment, expression levels of seven GmSAT genes were significantly increased in the roots, indicating their potential involvement in the plant’s adaptation to salt stress. GmSAT genes appear to play crucial roles in soybean’s response to salt stress, offering insights that could aid in the development of salt-tolerant soybean varieties.

WNK kinases are a unique class of serine/threonine protein kinases that lack a conserved catalytic lysine residue in the kinase domain. They are involved in various physiological processes in plants, such as circadian rhythm, flowering time, and stress response. In this study, we identified 26 WNK genes in soybean, a globally important crop, and analyzed their phylogenetic relationships, gene structures, conserved motifs, chromosomal distribution, cis-regulatory elements, and expression patterns. We found that soybean WNK genes were unevenly distributed on 15 chromosomes and underwent 21 segmental duplication events during evolution. We also detected 14 types of cis-regulatory elements in the promoters of WNK genes, indicating their potential involvement in different signaling pathways. Moreover, we observed tissue-specific and salt stress-responsive expression of WNK genes in soybean by using FPKM data and qRT-PCR analysis. We found that most WNK genes were significantly up-regulated by salt stress within 3 hours in both roots and leaves, except for WNK5, which showed a distinct expression pattern. Our findings provide valuable insights into the molecular characteristics and evolutionary history of the soybean WNK gene family and lay a foundation for further functional analysis of WNK genes in soybean.