Plant architecture traits are closely related to plant biomass, lodging, and photosynthetic efficiency, which in turn affect soybean yield. In this study, we investigated a Chinese soybean mini core collection consisting of 224 germplasm accessions for four plant architecture-related traits (plant height (PH), number of nodes on main stem (NN), branch number (BN), and stem diameter (DI)) under three environments and conducted a genome-wide association study (GWAS) based on 1514 single nucleotide polymorphisms (SNPs). A total of 41 SNPs were found to be significantly associated with PH, NN, BN, and DI in two or more environments. Among these SNPs, 15 were located in regions in which plant architecture-related QTLs had been reported in previous studies, and 26 were new genetic loci. In addition, 18 potential candidate genes for plant architecture-related traits were obtained by predicting the genes in the interval of four large-effect markers (BARC-017097-02199, Map-2213, BARC-014639-01604, and Map-2223). This research will help to illuminate the genetic basis of soybean plant architecture-related traits and accelerate the process of plant architecture breeding by molecular marker-assisted selection in soybean.

The mediator complex is an essential link between transcription factors and RNA polymerase II, and mainly functions in the transduction of diverse signals to genes involved in different pathways. Limited information is available on the role of soybean mediator subunits in growth and development, and their participation in defense response regulation. Here, we performed genome-wide identification of the 95 soybean mediator subunits, which were unevenly localized on the 20 chromosomes and only segmental duplication events were detected. We focused on GmMED16-1, which is highly expressed in the roots, for further functional analysis. Transcription of GmMED16-1 was induced in response to Phytophthora sojae infection. Agrobacterium rhizogenes mediated soybean hairy root transformation was performed for the silencing of the GmMED16-1 gene. Silencing of GmMED16-1 led to an enhanced susceptibility phenotype and increased accumulation of P. sojae biomass in hairy roots of transformants. The transcript levels of NPR1, PR1a, and PR5 in the salicylic acid defense pathway in roots of GmMED16-1-silenced transformants were lower than those of empty-vector transformants. The results provide evidence that GmMED16-1 may participate in the soybean–P. sojae interaction via a salicylic acid-dependent process.

Arachis pintoi Krapov. & W.C.Greg. is an important leguminous forage grass species that have extremely wide ranges of distribution in the tropical and sub-tropical regions. It has high feeding value and horticultural value. In this study, we sequenced and assembled the complete chloroplast genome of A. pintoi. The chloroplast genome is 156,185 bp in length, containing a pair of inverted repeated (IR) regions of 25,820 bp that are separated by a large single copy (LSC) region of 85,637 bp, and a small single copy (SSC) region of 18,908 bp. The complete chloroplast genome contains 112 unique genes, including 80 protein-coding genes, 28 transfer RNA genes (tRNAs), and four ribosomal RNA genes (rRNAs). The overall GC content was 36.4%. The phylogenetic analysis demonstrated that A. pintoi formed a single branch among genus Arachis. The whole chloroplast genome of A. pintoi will be a useful resource for future studies on phylogeny and conservation in Arachis.

Peanut (Arachis hypogaea L.) is a prominent legume and oilseed crop cultivated globally for its economic significance and nutritional value. With the growing demand for edible oil and protein, peanut cultivation needs to be expanded into salinized land. However, salt stress in such soils severely limits peanut growth and productivity. The Na⁺/H⁺ antiporter (NHX) gene family plays a crucial role in plant salt tolerance by regulating ion homeostasis. Genome-wide identification of peanut NHX genes and systematic profiling of their expression patterns under salt stress are essential for enhancing peanut salt tolerance through molecular breeding. In this study, we conducted a genome-wide analysis of the NHX gene family in cultivated peanut and identified 73 AhNHX genes. Based on NHX protein sequences from Arabidopsis thaliana, Glycine max, Medicago sativa, Medicago truncatula, and Phaseolus vulgaris, a phylogenetic tree was constructed, and the 73 AhNHX genes were divided into three clades. Furthermore, analysis of gene structure and conserved motifs revealed that intron size, intron number, and motif number differed significantly among subfamilies. Collinearity analysis indicated that segmental duplication events were the primary driver of AhNHX family expansion. The dN/dS ratio was less than one, implying that the AhNHX gene family experienced strong purifying selection during long‑term evolution. Expression profiling across 22 tissues showed that 27 AhNHX genes exhibited tissue‑specific expression patterns. Under salt stress, transcript levels of multiple AhNHX genes were differentially regulated between the salt‑tolerant variety (HY33) and the salt‑sensitive variety (HY9115). Based on representative features in gene structure, protein sequence, evolutionary lineage, and salt‑induced upregulation, 12 genes (AhNHX11, 12, 19, 23, 34, 38, 43, 44, 48, 54, 57, and 73) were identified as candidates for further functional characterization. This study provides comprehensive insights into the AhNHX gene family and pinpoints candidate genes for improving salt tolerance in peanut via molecular breeding.