Copper (Cu) is an essential micronutrient for almost all organisms; however, the genetic basis regarding copper accumulation remains unclear. In the present study, a genome-wide association study (GWAS) was performed on the Cu concentration in grains of 207 wheat accessions based on five multi-locus models (FASTmrMLM, ISIS EM-BLASSO, mrMLM, pKWmEB, pLARmEB). A total of 86 significant quantitative trait nucleotides (QTNs) were identified using five methods, with the mrMLM model detecting the fewest QTNs, only 12, while the other four models detected 21–40 QTNs. Thirty stable QTNs were detected in multiple environments or multiple models, mainly distributed on chromosomes 2A, 4B, 2B, and 5A, explaining 0.5–29.3% of the phenotypic variation. Finally, five potential candidate genes associated with Cu absorption and transport in the genomic regions near the reliable QTNs were screened out, including TraesCS2A02G505500 and TraesCS4B02G019300 (zinc transporters), TraesCS2B02G313200 (copper transporter), TraesCS3A02G042600 and TraesCS3B02G040900 (metal tolerance protein). These findings provide new insights into the genetic basis for Cu accumulation in wheat grains and demonstrate the role of the multi-locus GWAS (ML-GWAS) method.

Sorghum (Sorghum bicolor), a drought- and salt-tolerant staple cereal, supports over 500 million people globally as food, fiber, and fuel. Auxin/Indole-3-Acetic Acid (Aux/IAA) proteins regulate auxin signaling for plant growth and stress responses. However, the Aux/IAA gene family in sorghum has not yet been comprehensively analyzed. In this study, a total of 42 SbAUX genes were identified, and phylogenetic analysis revealed that the SbAUXs could be clustered into five subfamilies. Structural analysis further revealed that these subfamilies exhibit distinct structural features, while structures remain relatively conserved within each subfamily. The expansion of SbAUX genes has been mediated by multiple duplication types, with whole-genome duplication (WGD) events identified as the predominant driving force. Interspecific collinearity analysis revealed that AUX genes have undergone purifying selection. Promoter analysis revealed that the SbAUX gene promoters contain stress-responsive elements including as-1 and STRE, and transcriptome analysis combined with RT-qPCR data implied a potential involvement of SbAUX genes in the response to salt and PEG stresses. These findings provide a preliminary theoretical basis for exploring sorghum’s molecular responses to stress, and the SbAUX genes identified herein might represent potential candidate genes for genetic improvement in sorghum.

Cowpea (Vigna unguiculata L.), a crucial global legume crop for food security, faces significant challenges in yield and quality due to NaCl stress, which

Bread wheat (Triticum aestivum L.) is one of the most extensively cultivated cereal crops around the world. Here, we investigated the population structure and genetic diversity of a panel mainly originated from two wheat agro-ecological regions (northern winter wheat region, NW; and the Huang-Huai River Valley’s facultative wheat region, HH) in China based on a 15K SNP array. Population genetic analysis revealed that the optimal population number (K) was three, and the three groups were roughly related to ecological regions, including NW (mainly Hebei), HH1 (Henan-Shaanxi), and HH2 (Shandong). Within HH, HH1 had a higher nucleotide diversity (π = 0.31167), minor allele frequency (MAF = 0.2663), polymorphism information content (PIC = 0.2668), and expected heterozygosity (H_exp = 0.3346) than HH2. Furthermore, our results demonstrated that genetic diversity decreases with the advancement of wheat breeding. Finally, inference of ancestry informative markers indicated that the genomes of the three pure groups from the three provinces (Hebei, Henan, and Shandong) of the two regions have genomic regions with different mosaic patterns derived from the two landrace groups. These findings may facilitate the development of wheat breeding strategies to target novel desired alleles in the future.